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off - line pwm control lers with integrated power mosfet STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 1 jan. 28 , 2 01 4 general descriptions the STR3A100 series are power ics for switching power supplies, incorporating a mosfet and a current mode pwm controller ic. the low standby power is accomplished by the automatic switching between the pwm operati on in normal operation and the burst - oscillation under light load conditions. the product achieves high cost - performance power supply systems with few external components. features ? low thermal resistance package ? current mode type pwm control ? soft start function ? no load power consumption < 15mw ? auto standby function normal operation ----------------------------- pwm mode standby ---------------------------- burst oscillation mode ? random switching function ? slope compe n sation function ? leading edge blanking function ? bias assist function ? protections ? two types of overcurrent protection (ocp) ; pulse - by - pulse , built - in compensation circuit to minimize ocp point variation on ac input voltage ? overload protection (olp) ; a uto - r estart ? overvoltage protection (ovp) ; latched shutdown or a uto - r estart ? thermal shutdown protection (tsd) ; latched shutdown or auto - restart typical application circuit package dip8 not to scale lineup ? electrical characteristics products f osc(avg) v d ss(min) (max.) ovp /tsd str3a1 67 khz 650 v latched shutdown str3a1 d 67 khz 650 v a uto r estart str3a1 hd 100 khz 700 v a uto r estart ? mosfet on resistance and output power , p out * products r ds(on) (max.) p out ( adapter ) p out (open frame) ac230v ac85 ~265v ac230v ac85 ~265v f osc(avg) = 67 khz str3a 1 5 1 4.0 29.5 w 19.5 w 37 w 23 w str3a 1 5 1 d str3a 1 5 2 3.0 33 w 23.5 w 45 w 29 w str3a 1 5 2 d str3a 1 53 1.9 3 7 w 27.5 w 53 w 3 5 w str3a 1 53d str3a 1 5 4 1.4 41 w 31 w 60 w 40 w str3a 1 5 4 d str3a 1 55 1. 1 4 5 w 35 w 65 w 44 w str3a 1 55d f osc(avg) = 100 khz str3a161hd 4.2 25 w 20 w 36 w 24 w str3a162hd 3.2 28 w 23 w 40 w 28 w str 3a163hd 2.2 32 w 25.5 w 46 w 33.5 w * the output power is based on the thermal ratings, and the peak output power can be 120 to 140 % of the value stated here. at low output voltage, small core and short on duty, the output power may be less than the value stated here. applications ? low power ac/dc adapter ? white goods ? auxiliary power supply ? other smps http://www.sanken - ele.co.jp/en/ v a c c 1 c 5 r 1 d 1 d 2 r 2 c 2 t 1 d 5 1 c 5 1 r 5 1 r 5 2 u 2 r 5 4 r 5 6 c 5 2 d p s p c 1 p c 1 c 3 r o c p b r 1 r 5 3 r 5 5 l 5 1 c 5 3 c 4 v o u t g n d 1 2 3 4 d / s t d / s t v c c n c s / o c p f b / o l p g n d d / s t d / s t 8 7 6 5 s t r 3 a 1 0 0 u 1 c y
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 2 jan. 28 , 2 01 4 contents general descriptions -------------------------------- -------------------------------- ------- 1 1. absolute maximum ratings -------------------------------- ------------------------- 3 2. electrical characteristics -------------------------------- ---------------------------- 4 3. performance curves -------------------------------- -------------------------------- -- 6 3.1 derating curves -------------------------------- ------------------------------- 6 3.2 mosfet safe operating area curves -------------------------------- -- 6 3.3 ambient temperature versus power dissipation curves ------------ 8 3.4 transient thermal resistance curves -------------------------------- --- 8 4. functional block diagram -------------------------------- -------------------------- 10 5. p in configuration definitions -------------------------------- ---------------------- 10 6. typical application circuit -------------------------------- ------------------------ 11 7. package outline -------------------------------- -------------------------------- ------- 12 8. marking diagram -------------------------------- -------------------------------- ---- 12 9. operational description -------------------------------- ----------------------------- 13 9.1 startup operation -------------------------------- --------------------------- 13 9.2 undervoltage lockout (uvlo) -------------------------------- ----------- 13 9.3 bias assist function -------------------------------- ------------------------- 13 9.4 soft start function -------------------------------- -------------------------- 14 9.5 constant output voltage control -------------------------------- -------- 14 9.6 leading edge blanking function -------------------------------- -------- 15 9.7 random switching function -------------------------------- -------------- 15 9.8 automatic standby mode function -------------------------------- ------ 15 9.9 overcurrent protection function (ocp) ------------------------------- 15 9.10 overload protection function (olp) -------------------------------- --- 16 9.11 overvoltage protection (ovp) -------------------------------- ------------ 17 9.12 thermal shutdown function (tsd) -------------------------------- ----- 17 10. design notes -------------------------------- -------------------------------- ----------- 18 10.1 external components -------------------------------- ----------------------- 18 10.2 pcb trace layout and component placement ----------------------- 19 11. pattern layout example -------------------------------- ---------------------------- 21 12. reference design of power supply -------------------------------- --------------- 22 operating precautions -------------------------------- ------------------------ 24 important notes -------------------------------- -------------------------------- --- 25
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 3 jan. 28 , 2 01 4 1. absolute maximum ratings ? the polarity value for current specifies a sink as "+," and a source as "?," referencing the ic. ? unless otherwise specified t a = 25 c , 5 pin = 6 pin = 7 pin = 8 pin parameter symbol test conditions pins rating units notes drain peak current ( 1 ) i dpeak single pulse 8 C 3a151 / 51d / 61hd 4 3a152 / 52d / 62hd 4.8 3a163hd 5.2 3a153 / 53d 6.4 3a154 / 54d 7.2 3a155 / 55d avalanche energy ( 2 )( 3 ) e as i lpeak = 2.13 a 8 C 3a151 / 51d i lpeak = 2.19 a 56 3a152 / 52d i lpeak = 2.46 a 72 3a153 / 53d i lpeak = 2.66 a 83 3a154 / 54d i lpeak = 3.05 a 110 3a155 / 55d i lpeak = 1.43 a 23.8 3a161hd i lpeak = 1.58 a 29 3a162hd i lpeak = 1.88 a 41 3a163hd s/ocp pin voltage v s/ ocp 1 ? ? vcc pin voltage v cc 2 ? fb/olp pin voltage v fb 4 ? ? fb/olp pin sink current i fb 4 ? mosfet power dissipation ( 4 ) p d1 ( 5 ) 8 C 3a151 / 51d / 52 / 52d / 61hd / 62hd 1.76 3a153 / 53d / 54 / 54d / 63hd 1.81 3a155 / 55d control part power dissipation p d2 2 C v cc i cc operating ambient temperature t op D ? stg D ? ch D ( 1 ) refer to figure 3 - 1 soa temperature derating coefficient curve ( 2 ) refer to figure 3 - 2 avalanche energy derating coefficient curve ( 3 ) single pulse, v dd = 99 v, l = 20 mh ( 4 ) refer to section 3.3 ta - p d1 cu r ve ( 5 ) when embedding this hybrid ic onto the printed circuit board (cupper area in a 15 mm 15 mm)
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 4 jan. 28 , 2 01 4 2. electrical characteristics ? the polarity value for current specifies a sink as "+," and a source as "?," referencing the ic. ? unless otherwise specified, t a = 25 c , v cc = 18 v , 5 pin = 6 pin = 7 pin = 8 pin , v fb = 3 v , v d/st = 10 v parameter symbol test conditions pins min. typ. max. units notes power supply startup operation operation start voltage v cc(on) 2 ? ( 1 ) v cc(off) 2 ? cc(on) v cc = 12v 2 ? ? ? st(on) 8 ? ? ? startup v cc = 13.5v 2 ? ? ? ? cc(bias) 2 ? pwm operation average pwm switching frequency f osc(avg) 8 ? 3a15 3a15 d 90 100 110 3a16 hd pwm frequency modulation deviation ? ? ? 3a15 3a15 d ? ? 3a16 hd maximum on duty d max 8 ? 3a15 3a15 d 77 83 89 % 3a16 hd protection function leading edge blanking time t bw ? ? ? 3a15 3a15 d ? ? 3a16 hd ocp compensation coefficient dpc ? ? ? mv/s 3a15 3a15 d ? ? 3a16 hd ocp compensation on duty d dpc ? ? ? ocp threshold voltage at zero on duty v ocp(l) 1 ? ocp threshold voltage at 36% on duty v ocp(h) 1 ? maximum feedback current i fb(max) 4 ? ? ? ? minimum feedback current i fb(min) 4 ? ? ? ? fb/olp pin oscillation stop threshold voltage v fb(off) v cc =32v 4 ? 3a151 / 51d / 52 / 52d / 53 / 53d / 61hd / 62hd / 63hd 0.85 0.98 1.09 3a154 / 54d / 55 / 55d olp threshold voltage v fb(olp) v cc = 32v 4 ? olp operation current i cc(olp) v cc = 12v 2 ? ? ? a olp delay time t olp ? ( 1 ) v cc(bias) > v cc(off) always.
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 5 jan. 28 , 2 01 4 parameter symbol test conditions pins min. typ. max. units notes fb/olp pin clamp voltage v fb(clamp) 4 ? 3 11 .0 12.8 14 .0 v ovp threshold voltage v cc(ovp) 2 ? 3 27.5 29.5 31.5 v thermal shutdown operating temperature t j(tsd) ? 13 5 ? ? c mosfet drain - to - source breakdown voltage v dss 8 C 1 650 ? ? v 3a15 3a15 d 700 ? ? 3a16 hd drain leakage current i dss 8 C 1 ? ? 300 a on resistance r ds(on) i ds = 0.4a 8 ? 1 ? ? 4.2 3a161hd ? ? 4.0 3a151 / 51d ? ? 3.2 3a162hd ? ? 3.0 3a152 / 52d ? ? 2.2 3a163hd ? ? 1.9 3a153 / 53d ? ? 1.4 3a154 / 54d ? ? 1.1 3a155 / 55d switching time t f 8 C 1 ? ? 250 ns thermal resistance channel to frame ch - f ? ? ? 16 c/w channel to case thermal resistance ( 2 ) ch - c ? ? ? 18 c/w 3a151 / 51d / 52 / 52d / 53 / 53d / 61hd / 62hd / 63hd ? ? 17 3a154 / 54d / 55 / 55d ( 2 ) ch - c is thermal resistance between channel and case. case temperature (t c ) is measured at the center of the case top surface.
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 6 jan. 28 , 2 01 4 3. performance curves 3.1 derating cu r ves figure 3 - 1 soa temperature derating coefficient curve figure 3 - 2 avalanche energy derating coefficient curve 3.2 mosfet safe operating area curve s ? when the ic is used, the safe operating area curve should be multiplied by the temperature derating c oefficient derived from figure 3 - 1 . ? the broken line in the safe operating area curve is the drain current curve limited by on - resistance. ? unless otherwise specified, t a = 25 c , single pulse ? str3a151 / 51 d ? str3a15 2 / 52d 0 20 40 60 80 100 0 25 50 75 100 125 150 safe operating area temperature derating coefficient (%) channel temperature, tch ( c) 0 20 40 60 80 100 25 50 75 100 125 150 e as temperature derating coefficient (%) channel temperature, tch ( c) 0.01 0.1 1 10 1 10 100 1000 drain current, i d (a) drain - to - source voltage (v) 0.1ms 1ms 0.01 0.1 1 10 1 10 100 1000 drain current, i d (a) drain - to - source voltage (v) 0.1ms 1ms
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 7 jan. 28 , 2 01 4 ? str3a1 53 / 53d ? str3a1 54 / 54d ? str3a1 55 / 55d ? str3a1 61hd ? str3a1 62hd ? str3a1 63hd 0.01 0.1 1 10 1 10 100 1000 drain current, i d (a) drain - to - source voltage (v) 0.1ms 1ms 0.01 0.1 1 10 1 10 100 1000 drain current, i d (a) drain - to - source voltage (v) 0.1ms 1ms 0.01 0.1 1 10 1 10 100 1000 drain current, i d (a) drain - to - source voltage (v) 0.1ms 1ms 0.01 0.1 1 10 1 10 100 1000 drain current, i d (a) drain - to - source voltage (v) 0.1ms 1ms 0.01 0.1 1 10 1 10 100 1000 drain current, i d (a) drain - to - source voltage (v) 0.1ms 1ms 0.01 0.1 1 10 1 10 100 1000 drain current, i d (a) drain - to - source voltage (v) 0.1ms 1ms
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 8 jan. 28 , 2 01 4 3.3 ambient temperature versus power dissipation curve s ? str3a151 / 51 d / 52 / 52d / 6 1 hd / 62hd ? str3a15 3 / 5 3d / 54 / 54d / 63hd ? str3a1 55 / 55d 3.4 transient thermal resistance curve s ? str3a151 / 51d / 61hd 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0 25 50 75 100 125 150 power dissipation, p d1 (w) ambient temperature, t a ( p d1 = 1.68 w 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0 25 50 75 100 125 150 power dissipation, p d1 (w) ambient temperature, t a ( p d1 = 1.76 w 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0 25 50 75 100 125 150 power dissipation, p d1 (w) ambient temperature, t a ( c ) p d1 =1.81w 1 10 100 1m 10m 100m time (s) 10 1 0.1 0.01 transient thermal resistance ch - c ( c /w)
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 9 jan. 28 , 2 01 4 ? str3a15 2 / 52d / 62hd ? str3a15 3 / 53d / 63hd ? str3a15 4 / 54d ? str3a15 5 / 55d 1 10 100 1m 10m 100m time (s) 10 1 0.1 0.01 transient thermal resistance ch - c ( c /w) 1 10 100 1m 10m 100m time (s) 10 1 0.1 0.01 transient thermal resistance ch - c ( c /w) 1 10 100 1m 10m 100m time (s) 10 0 10 1 0.1 0.01 transient thermal resistance ch - c ( c /w) 1 10 100 1m 10m 100m time (s) 10 1 0. 1 0. 0 1 0.0 0 1 transient thermal resistance ch - c ( c /w)
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 10 jan. 28 , 2 01 4 4. functional block diagram 5. pin configuration definitions pin name descriptions 1 s/ocp mosfet source and overcurrent protection (ocp) signal input 2 vcc power supply voltage inpu t for control part and overvoltage protection (ovp) signal input 3 gnd ground 4 fb /olp c onstant voltage control signal input and over load protection (olp) signal input 5 d /st mosfet drain and startup current input 6 7 8 v cc d/st s/ocp gnd fb/olp 2 4 5~8 1 3 1 5 6 7 8 4 3 2 s / ocp vcc gnd fb / olp d / st d / st d / st d / st
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 11 jan. 28 , 2 01 4 6. typical application circuit ? the pcb traces d/st pins should be as wide as possible, in order to enhance thermal dissipation. ? in applications having a power supply specified such that d/st pin has large transient surge voltages, a clamp snubber circuit of a capacitor - resistor - diode (crd) combination should be added on the primary winding p, or a damper snubber circuit of a capacitor (c) or a resistor - capacitor (rc) combination should be added b etween the d/st pin and the s/ ocp pin. figure 6 - 1 typical application circuit v a c c 1 c 5 r 1 d 1 d 2 r 2 c 2 t 1 d 5 1 c 5 1 r 5 1 r 5 2 u 2 r 5 4 r 5 6 c 5 2 d p s p c 1 p c 1 c 3 r o c p b r 1 r 5 3 r 5 5 l 5 1 c 5 3 c 4 v o u t g n d 1 2 3 4 d / s t d / s t v c c n c s / o c p f b / o l p g n d d / s t d / s t 8 7 6 5 s t r 3 a 1 0 0 u 1 c y c r d c l a m p s n u b b e r c r c d a m p e r s n u b b e r
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 12 jan. 28 , 2 01 4 7. package outline ? dip8 8. marking diagram notes: 1) dimension is in millimeters 2) pb - free. device composition compliant with the rohs directive 1 8 p a r t n u m b e r 3 a 1 y m d s a n k e n c o n t r o l n u m b e r l o t n u m b e r y = l a s t d i g i t o f y e a r ( 0 - 9 ) m = m o n t h ( 1 - 9 , o , n o r d ) d = p e r i o d o f d a y s ( 1 t o 3 ) 1 : 1 s t t o 1 0 t h 2 : 1 1 t h t o 2 0 t h 3 : 2 1 s t t o 3 1 s t
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 13 jan. 28 , 2 01 4 9. operational description ? all of the parameter values used in these descriptions are typical values, unless they are specified as minimum or maximum. ? with regard to current direction, "+" indicates sink current (toward the ic) and " C " indicates source current (from the ic). 9.1 startup operation figure 9 - 1 shows the circuit around vcc pin. the ic incorporates the startup circuit. the circuit is connected to d/st pin. when d/st pin voltage reaches to startup circuit operation voltage v st(on) = 40 v , the startup circuit starts operation. during the startup process, the constant current, i startup = ? 2.5 ma , charges c2 at vcc pin. when vcc pin voltage increases to v cc(on) = 15.3 v , the control circuit starts switching operation. during the ic operation, the voltage rectified the auxiliary winding voltage, v d , of figure 9 - 1 becomes a power source to the vcc pin. after switching operation begins, the startup circuit turns off automatically so that its current consumption becomes zero. the approximate value of auxiliary wind ing voltage is about 1 8 v, taking account of the winding turns of d winding so that vcc pin voltage becomes equation ( 1 ) within the specification of inp ut and output voltage variation of power supply. ? start is calculated as follows: ( 2 ) where, t start : startup time of ic (s) v cc(int) : initial voltage on vcc pin (v) figure 9 - 1 vcc pin peripheral circuit 9.2 undervoltage lockout (uvlo) figure 9 - 2 shows the relationship of vcc pin voltage and circuit current i cc . when vcc pin voltage decreases to v cc(off) = 8.1 v , the control circuit stops operation by uvlo (undervoltage lockout) circuit, and reverts to the state before startup. figure 9 - 2 relationship between vcc pin voltage and i cc 9.3 bias assist function figure 9 - 3 shows vcc pin voltage behavior during the startup period. after vcc pin voltage increases to v cc(on) = 15.3 v at startup, the ic starts the operation. then circuit current increases and vcc pin voltage decreases. at the same time, the auxiliary winding voltage v d increases in proportion to output voltage. these are all balanced to produce vcc pin voltage. figure 9 - 3 vcc pin voltage during startup peri od the surge voltage is induced at output winding at turning off a power mosfet. when the output load is light at startup, the surge voltage causes the unexpected feedback control. this results the lowering of the output power and vcc pin voltage. when the vcc pin voltage decreases to v cc(off) = 8.1 v , the ic stops switching operation and a startup failure occurs. in order to prevent this, the bias assist function is activated when the vcc pin voltage decreases to the startup current threshold ) v ( 0 . 27 v ) v ( 5 . 10 cc ? ? stratup ) int ( cc ) on ( cc start i v v c2 t ? v a c c 1 d 2 r 2 c 2 t 1 d p b r 1 v c c g n d d / s t 5 - 8 3 2 v d u 1 .) (min v v .) (max v ) ovp ( cc cc ) bias ( cc ? ? i c s t a r t s o p e r a t i o n v c c p i n v o l t a g e v c c ( o n ) v c c ( b i a s ) v c c ( o f f ) s t a r t u p f a i l u r e s t a r t u p s u c c e s s t a r g e t o p e r a t i n g v o l t a g e t i m e b i a s a s s i s t p e r i o d i n c r e a s e w i t h r i s i n g o f o u t p u t v o l t a g e c i r c u i t c u r r e n t , i c c i c c o n v c c o f f v c c o n v c c p i n v o l t a g e s t a r t s t o p
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 14 jan. 28 , 2 01 4 biasing voltage, v cc(bias) = 9.5 v . while the bias assist function is activated, any decrease of the vcc pin voltage is counteracted by providing the startup curr ent, i startup , from the startup circuit. thus, the vcc pin voltage is kept almost constant. by the bias assist function, the value of c2 is allowed to be small and the startup time becomes shorter. also, because the increase of vcc pin voltage becomes faster when the output runs with excess voltage, the response time of the ovp function becomes shorter. it is necessary to check and adjust the startup process based o n actual operation in the application, so that poor starting conditions may be avoided. 9.4 soft start function figure 9 - 4 shows the behavior of vcc pin voltage and drain current during the startup period. the ic activates the soft start circuitry during the startup period. soft start time is fixed to around 7 ms . during the soft start period, over current threshold is increased step - wisely ( 5 steps). this function reduces the voltage and the current stress of mosfet and secondary side rectifier diode. since the leading edge blanking function (refer to section 9.6 ) is deactivated during the soft start period, there is the case that on time is less than the leading edge blanking time, t bw = 350 ns . after the soft start period, d/st pin current, i d , is limited by the overcurrent protection (ocp) , until the output voltage increases to the target operating voltage. this period is given as t lim . in case t lim is longer than the olp delay time, t olp , the output power is limited by the olp protection operation (olp). thus, it is necessary to adjust the value of output capacitor and the turn ratio of auxiliary winding d so that the t lim is less than t olp = 54 ms (min.) . figure 9 - 4 v cc and i d behavior during startup 9.5 constant output voltage control the ic achieves the constant voltage control of the power supply output by using the current - mode control method, which enhances the response speed and provides the stable operation. the fb/olp pin voltage is internally added the slope compensation at the feedbac k control (refer to section 4 . functional block diagram ), and the target voltage, v sc , is generated. the ic compares the voltage, v rocp , of a current detection resistor with the target voltage, v sc , by the internal fb comparator, and controls the peak value of v rocp so that it gets close to v sc , as shown in figure 9 - 5 and figure 9 - 6 . figure 9 - 5 fb/olp pin peripheral circuit figure 9 - 6 drain current, i d , and fb comparator operation in steady operation ? light load conditions when load conditions become lighter, the output voltage, v out , increases. thus, the feedback current from the error amplifier on the secondary - side also increases. the feedback current is sunk at the fb/olp pin, transferred through a photo - coupler, pc1, and the fb/olp pin voltage decreases. thus, v sc decreases, and the peak value of v rocp is controlled t o be low, and the peak drain current of i d decreases. this control prevents the output voltage from increasing. v c c ( o n ) v c c ( o f f ) t i m e v c c p i n v o l t a g e s t a r t u p o f s m p s n o r m a l o p e r t i o n d / s t p i n c u r r e n t , i d t l i m < t o l p ( m i n . ) s o f t s t a r t p e r i o d a p p r o x i m a t e l y 7 m s ( f i x e d ) t i m e s t a r t u p o f i c t s t a r t l i m i t e d b y o c p o p e r a t i o n v s c f b c o m p a r a t o r d r a i n c u r r e n t , i d + - v o l t a g e o n b o t h s i d e s o f r o c p v r o c p t a r g e t v o l t a g e i n c l u d i n g s l o p e c o m p e n s a t i o n pc 1 c 3 r ocp 1 3 4 s / ocp fb / olp gnd u 1 i fb v rocp
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 15 jan. 28 , 2 01 4 ? heavy load conditions when load conditions become greater, the ic performs the inverse operation to that described above. thus, v sc increases and the peak drain current of i d increases. this control prevents the output voltage from decreasing. in the current mode control method, when the drain current waveform becomes trapezoidal in continuous operating mode, even if the peak current level set by the target voltage is constant, the on - time fluctuates based on the initial value of the drain current. this results in the on - time fluctuating in multiples of the fundamental operating frequency as shown in figure 9 - 7 . this is called the subharmonics phenomenon. in order to avoid this, the ic incorporates the slope com pensation function. because the target voltage is added a down - slope compensation signal, which reduces the peak drain current as the on - duty gets wider relative to the fb/olp pin signal to compensate v sc , the subharmonics phenomenon is suppressed. even if subharmonic oscillations occur when the ic has some excess supply being out of fe edback control, such as during startup and load shorted, this does not affect performance of normal operation. figure 9 - 7 drain current, i d , waveform in subharmonic oscillation 9.6 leading edge blanking function the ic uses the peak - current - mode control method for the constant voltage control of output. in peak - current - mode control method, there is a case that the power mosfet turns off due to unexpected response of fb comparator or overcurrent protection circuit (ocp) to the steep surge current in turning on a power mosfet. in order to prevent this response to the surge voltage in turning - on the power mosfet, the leading edge blanking, t bw = 350 ns ( str3a16hd for t bw = 280 ns ) is built - in. during t bw , the ocp threshold voltage becomes about 1. 7 v which is higher than the normal ocp threshold voltage ( refer to section 9.9 ). 9.7 random switching function the ic modulates its switching frequency randomly by superposing the modulating frequency on f osc(avg) in normal operation. this function reduces the conduction noise compared to others without this function, and simplifies noise filtering of the input lines of power supply. 9.8 automatic standby mode function automatic standby mode is activated automatically when the drain current, i d , reduces under light load conditions, at which i d is less than 20 % to 25 % (str3a154, 54d, 55 and 55d are 15 to 20 %) of the maximum drain current (it is in the ocp state). the operation mode becomes burst oscillation, as shown in figure 9 - 8 . burst oscillation mode reduces switching losses and improves power suppl y efficiency because of periodic non - switching intervals. generally, to improve efficiency under light load conditions, the frequency of the burst oscillation mode becomes just a few kilohertz. because the ic suppresses the peak drain current well during b urst oscillation mode, audible noises can be reduced. if the vcc pin voltage decreases to v cc(bias) = 9.5 v during the transition to the burst oscillation mode, th e bias assist function is activated and stabilizes the standby mode operation, because i startup is provided to the vcc pin so that the vcc pin voltage does not decrease to v cc(off) . however, if the bias assist function is always activated during steady - state operation including standby mode, the power loss increases. therefore, the vcc pin voltage should be more than v cc(bias) , for example, by adjusting the turns ratio of the auxiliary winding and secondary winding and/or reducing the value of r2 in figure 10 - 2 (refer to section 10.1 peripheral components for a detail of r2). figure 9 - 8 auto standby mode timing 9.9 overcurrent protection function (ocp) overcurrent protection function (ocp) detects each drain peak current level of a power mosfet on pulse - by - pulse basis, and limits the output power when t o n 1 t a r g e t v o l t a g e w i t h o u t s l o p e c o m p e n s a t i o n t o n 2 t t t normal operation standby operation normal operation burst oscillation output current , i out drain current , i d below several khz
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 16 jan. 28 , 2 01 4 the current level reaches to ocp t hreshold v oltage . during leading edge blanking time, the ocp threshold voltage becomes about 1.7 v which is higher than the normal ocp threshold voltage as shown in figure 9 - 9 . changing to this threshold voltage prevent s the ic from responding to the surge voltage in turning - on the power mosfet . this function operates as protection at the condition such as output windings shorted or unusual withstand voltage of secondary - side rectifier diodes. when power mosfet turns on, the surge voltage width of s/ocp pin should be less than t bw , as sho wn in figure 9 - 9 . in order to prevent surge voltage, pay extra attention to r ocp t race l ayout (refer to section 10.2 ). in addition, if a c (rc) damper snubber of figure 9 - 10 is used, reduce the ca pacitor value of damper snubber. figure 9 - 9 s/ocp pin voltage figure 9 - 10 damper snubber < input compensation f unction > ics with pwm control usually have some propagation delay time. the steeper the slope of the actual drain current at a high ac input voltage is, the larger the detection voltage of actual drain peak current is, compared to v oc p . thus, the peak current has some variation depending on the ac input voltage in ocp state. in order to reduce the variation of peak current in ocp state, the ic incorporates a built - in input compensation function. the input compensation f unction is the function of correction of ocp threshold voltage depending with ac input voltage, as shown in figure 9 - 11 . when ac input voltage is low (on duty is broad), the ocp threshold voltage is controlled to become high . the difference of peak drain current become small compared with the case where the ac input voltage is high (on duty is narrow). the compensation signal depends on on duty. the relation bet ween the on duty and the ocp threshold voltage after compensation v ocp ' is expressed as equation ( 3 ) . when on duty is broader than 36 %, the v ocp ' becomes a constant value v ocp(h) = 0.88 v figure 9 - 11 relationship between on duty and drain current limit after compensation ( 3 ) where, v ocp(l) : ocp threshold voltage at zero on duty dpc : ocp compensation coefficient ontime : on - time of power mosfet onduty : on duty of power mosfet f osc(avg) : average pwm switching frequency 9.10 overload protection function (olp) figure 9 - 12 shows the fb/olp pin peripheral circuit, and figure 9 - 13 shows each waveform for olp operation . when the peak drain current of i d is limited by ocp operation, the output voltage, v out , decreases and the feedback current from the secondary photo - coup ler becomes zero. thus, the feedback current, i fb , charges c3 connected to the fb/olp pin and the fb/olp pin c 1 t 1 d 5 1 r o c p u 1 c 5 1 c r c d a m p e r s n u b b e r 5 ~ 8 d / s t s / o c p 1 c r c d a m p e r s n u b b e r ) avg ( osc ) l ( ocp f onduty dpc v ? ? ? s u r g e p u l s e v o l t a g e w i d t h a t t u r n i n g o n t b w a b o u t 1 . 7 v v o c p ontime dpc v ' v ) l ( ocp ocp ? ? ? o n d u t y ( % ) d d p c = 3 6 % v o c p ( l ) 0 d m a x = 7 4 % 1 0 0 v o c p ( h ) 0 . 5 1 . 0 5 0 o c p t h r e s h o l d v o l t a g e a f t e r c o m p e n s a t i o n , v o c p '
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 17 jan. 28 , 2 01 4 voltage increases. when the fb/olp pin voltage increases to v fb(olp) = 8.1 v or more for the olp delay time, t olp = 70 ms or more , the olp function is activated , the ic stops switching operation. during olp operation , bias assist function is disabled . t hus, vcc pin voltage decreases to v cc(off) , the control circuit stops operation. after that, the ic reverts to the initial state by uvlo circuit, and the ic starts operation when vcc pin voltage increases to v cc(on) by s tartup c urrent. thus the intermittent operation by uvlo is repeated in olp state . this intermittent operation reduces the stress of parts such as power mosfet and secondary side rectifier diode. in addition, this operation reduces power consumpt ion because the switching period in this intermittent operation is short compared with oscillation stop period. when the abnormal condition is removed, the ic returns to normal operation automatically. figure 9 - 12 fb/olp pin peripheral circuit figure 9 - 13 olp operational waveforms 9.11 overvoltage protection (ovp) when a voltage between vcc pin and gnd terminal increases to v cc(ovp) = 29.5 v or more, ovp f unction is activated. the ic has two operation types of ovp function. one is latched shutdown . t he other is auto restart. in case the vcc pin voltage is provided by using auxiliary winding of transformer, the overvoltage conditions such as output voltage detection circuit open can be detected because the vcc pin voltage is proportional to output voltage. the approxim ate value of output voltage v out(ovp) in ovp condition is calculated by using equation ( 4 ) . 29.5 ( v ) ( 4 ) where, v out(normal) : output voltage in normal operation v cc(normal) : vcc pin voltage in normal operation ? latched shutdown type: str3a 1 when the ovp function is activated, the ic stops switching operation at the latched state. in order to keep the latched state, when vcc pin voltage decreases to v cc(bias) , the bias assist function is activated and vcc pin voltage is kept to over the v cc(off) . releasing the latched state is done by turning off the input voltage and by dropping the vcc pin voltage below v cc(off) . ? auto restart type: str3a 1 d when the ovp function is activated, the ic stops switching operation. during ovp operation, the bias assist function is disabled , the intermittent operation by uvlo is repeated like olp state ( refer to section 9.10 ). when the fault condition is removed, the ic returns to normal operation automatically (refer to figure 9 - 14 ) . figure 9 - 14 o v p operational waveforms 9.12 thermal shutdown function (tsd) when the temperature of control circuit increases to t j(tsd) = 13 5 c (min.) or more, thermal shutdown function (tsd) is activated . the ic has two operation t ypes of tsd function. one is latched shutdown, the other is auto restart. ? latched shutdown type: str3a 1 when the tsd function is activated, the ic stops ? ? ) normal ( cc ) normal ( out out(ovp) v v v p c 1 c 3 4 f b / o l p u 1 v c c 2 g n d 3 d 2 r 2 c 2 d v c c p i n v o l t a g e f b / o l p p i n v o l t a g e d r a i n c u r r e n t , i d v c c ( o f f ) v f b ( o l p ) t o l p v c c ( o n ) n o n - s w i t c h i n g i n t e r v a l t o l p v c c p i n v o l t a g e d r a i n c u r r e n t , i d v c c ( o f f ) v c c ( o n ) v c c ( o v p )
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 18 jan. 28 , 2 01 4 switching operation at the latched state. in order to keep the latched state, when vcc pin voltage decreases to v cc(bias) , the bias assist function is activated and vcc pin voltage is kept to over the v cc(off) . releasing the latched state is done by turning off the input voltage and by dropping the v cc pin voltage below v cc(off) . ? auto restart type: str3a 1 d when the tsd function is activated, the ic stops switching operation . during tsd operation, the bias assist function is disabled , the intermittent operation by uvlo is repeated like olp state ( ref er to section 9.10 ). when the fault condition is removed and the temperature decreases to less than t j(tsd) , t he ic returns to normal operation automatically . 10. design notes 10.1 external components take care to use p roperly rated, including derating as necessary and proper type of components. figure 10 - 1 the ic peripheral circuit ? output electrolytic capacitor apply proper derating to ripple current, voltage, and temperature rise. use of high ripple current and low impedance types, designed for switch mode power supplies, is recommended. ? s/ocp pin peripheral circuit i n figure 10 - 1 , r ocp is the resistor for the current detection. a high frequency switching current flows to rocp, and may cause poor operation if a high inductance resistor is used. choose a low inductance and high surge - tolerant type. ? vcc pin peripheral circuit the value of c2 in figure 10 - 1 is generally recommended to be 10 to 47f (refer to section 9.1 startup operation , because the startup time is determined by the value of c2) in actual power supply circuits, there are cases in which the vcc pin voltage fluctuates in proportion to the output current, i out (see figure 10 - 2 ), and the overvoltage protection function (ovp) on the vcc pin may be activated. this happens because c2 is charged to a peak voltage on the auxiliary winding d, which is caused by the transient surge voltage coupled from the primary winding when the power mosfet turns off. for alleviating c2 peak charging, it is effective to add some value r2, of several ten ths of ohms to several ohms, in series with d2 (see figure 10 - 1 ). the optimal value of r2 should be determined using a transformer matching what will b e used in the actua l application, because the vari ation of the auxiliary winding voltage is affected by the transformer structural design. figure 10 - 2 variation of vcc pin voltage and power ? fb/olp pin peripheral circuit figure 10 - 1 performs high frequency noise rejection and phase compensation, and s hould be connected close to these pins. the value of c3 is recommended to be about 2200 p f to 0.01f, and should be selected based on actual operation in the application. ? snubber circuit in case the serge voltage of v ds is large, the circuit should be adde d as follow s (see figure 10 - 1 ) ; ? a clamp snubber circuit of a capacitor - resistor - diode (crd) combination should be added on the primary winding p. ? a damper snubber circuit of a capacitor (c) or a resistor - capacitor (rc) c ombination should be added between the d/st pin and the s/ ocp pin. in case the damper snubber circuit is added, this components should be connected near d/st pin and s/ocp pin. ? phase compensation figure 10 - 3 shows the secondary side detection circuit v a c c 1 c 5 r 1 d 1 d 2 r 2 c 2 t 1 d p p c 1 c 3 r o c p b r 1 c 4 1 2 3 4 d / s t d / s t v c c n c s / o c p f b / o l p g n d d / s t d / s t 8 7 6 5 s t r 3 a 1 0 0 u 1 c r d c l a m p s n u b e r c r c d a m p e r s n u b b e r w i t h o u t r 2 w i t h r 2 v c c p i n v o l t a g e o u t p u t c u r r e n t , i o u t
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 19 jan. 28 , 2 01 4 with the standard shunt re gulator ic (u51) . c52 and r53 are for phase compensation. the value of c52 and r53 are recommended to be around 0.047f to 0.47f and 4.7 k to 470 k , respectively. they should be selected based on actual operation in the application. figure 10 - 3 peripheral circuit of secondary side shunt regulator (u51) ? transformer apply proper design margin to core temperature rise by core loss and copper loss. because the switching currents contain high frequency currents, the skin effect may become a consideration. choose a suitable wire gauge in consideration of the rms current and a current density of about 3 to 4a/mm 2 . if measures to further reduce temperature are still necessary, the following shoul d be considered to increase the total surface area of the wiring: ? increase the number of wires in parallel. ? use litz wires. ? thicken the wire gauge. fluctuation of the vcc pin voltage by i out worsens in the following cases, requiring a transformer designer to pay close attention to the placement of the auxiliary winding d: ? poor coupling between the primary and secondary windings (this causes high surge voltage and is seen in a design with low output voltage and high output current) ? poor coupling between the auxiliary winding d and the secondary stabilized output winding where the output line voltage is controlled constant by the output voltage feedback (this is susceptible to surge voltage) in order to reduce the influence of surge voltage on the vcc pin, figure 10 - 4 shows winding structural examples that are considered the placement of the auxiliary winding d. figure 10 - 4 winding structural examples ? winding structural example (a): separating the auxiliary winding d from the primary windings p1 and p2. where: p1 and p2 are windings divided the primary winding into two. ? winding structural example (b): placing the auxiliary winding d within the secondary - side stabilized output winding, s1, in order to improve the coupling of those windings. where: s1 is a stabilized out put winding of secondary - side windings, controlled to constant voltage. 10.2 pcb trace layout and component placement since the pcb circuit trace design and the component layout significantly affects operation, emi noise, and power dissipation , the high frequen cy pcb trace should be low impedance with small loop and wide trace. in addition, the ground traces affect radiated emi noise, and wide, short traces should be taken into account. figure 10 - 5 shows the circuit design example. (1) main circuit trace layout: s/ ocp pin to r ocp to c 1 to t1 (winding p) to d /st pin this is the main trace containing switching currents, and thus it should be as wid e trace and sm all loop as possible. if c 1 and the ic are distant from each other, placing a capacitor such as film capacitor (about 0.1 f and with proper voltage rating) close to the transformer or the ic is recommended to reduce impedance of the hi gh frequency current loop. (2) control ground trace layout since the operation of ic may be affected from the m a r g i n t a p e m a r g i n t a p e m a r g i n t a p e m a r g i n t a p e p 1 s 1 p 2 s 2 d p 1 s 1 d s 2 s 1 p 2 w i n d i n g s t r u c t u r a l e x a m p l e ( a ) w i n d i n g s t r u c t u r a l e x a m p l e ( b ) p 1 p 2 p r i m a r y m a i n w i n d i n g d p r i m a r y a u x i l i a r y w i n d i n g s 1 s e c o n d a r y s t a b i l i z e d o u t p u t w i n d i n g s 2 s e c o n d a r y o u t p u t w i n d i n g b o b b i n b o b b i n d 5 1 c 5 1 r 5 1 r 5 2 u 5 1 r 5 4 r 5 6 c 5 2 s p c 1 r 5 3 r 5 5 l 5 1 c 5 3 v o u t g n d t 1
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 20 jan. 28 , 2 01 4 large current of the main trace that flows in control ground trace, the control ground trace should be separate d from main trace and connected at a si ngle point grounding of point a in figure 10 - 5 as close to the r ocp pin as possible. (3) vcc trace layout : gnd pin to c 2 (negative) to t1 (winding d ) to r 2 to d2 to c 2 ( positive ) to vcc pin this is the trace for supplying power to the ic, and thus it should be as small loop as possible. if c 2 and the ic are distant from each other, placing a capacitor such as film capacitor c f ( about 0.1 f to 1.0 f) close to the vcc pin and the gnd pin is recommended. (4) r ocp trace layout r ocp should be placed as close as possible to the s/ ocp pin. the connection between the power ground of the main trace and the ic ground should be at a single point ground (point a in figure 10 - 5 ) which is close to the base of r ocp . (5) fb/olp trace layout the components connected to fb/olp pin should be as close to fb/olp pin as possible. the trace between the components and fb/olp pin should be as short as pos sible. (6) secondary rectifier smoothing circuit trace layout : t1 (winding s ) to d5 1 to c5 1 th is is the trace of the rectifier smoothing loop, carr ying the switching current , and thus it should be as wide trace and small loop as possible. if this trace is thin and long, inductance resulting from the loop may increase surge voltage at turning off the power mosfet. proper rectifier smoothing trace layout helps to increase margin against the power mosfet breakdown voltage, and reduces s tress on the clamp sn ubber circuit and losses in it. (7) thermal c onsideration s because the power mosfet has a positive thermal coefficient of r ds(on) , consider it in thermal design. since the copper area under the ic and the d/st pin trace act as a heatsink, its traces should be as wide as possible. figure 10 - 5 peripheral circuit example around the ic c 1 c 5 r 1 d 1 d 2 r 2 c 2 t 1 c 5 1 d p s p c 1 c 3 r o c p c 4 1 2 3 4 d / s t v c c n c s / o c p f b / o l p g n d 8 7 5 s t r 3 a 1 0 0 u 1 a d s t c y d 5 1 ( 1 ) m a i n t r a c e s h o u l d b e w i d e t r a c e a n d s m a l l l o o p ( 6 ) m a i n t r a c e o f s e c o n d a r y s i d e s h o u l d b e w i d e t r a c e a n d s m a l l l o o p ( 7 ) t r a c e o f d / s t p i n s h o u l d b e w i d e f o r h e a t r e l e a s e ( 2 ) c o n t r o l g n d t r a c e s h o u l d b e c o n n e c t e d a t a s i n g l e p o i n t a s c l o s e t o t h e r o c p a s p o s s i b l e ( 3 ) l o o p o f t h e p o w e r s u p p l y s h o u l d b e s m a l l ( 4 ) r o c p s h o u l d b e a s c l o s e t o s / o c p p i n a s p o s s i b l e . ( 5 ) t h e c o m p o n e n t s c o n n e c t e d t o f b / o l p p i n s h o u l d b e a s c l o s e t o f b / o l p p i n a s p o s s i b l e 6 d / s t d / s t d / s t
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 21 jan. 28 , 2 01 4 11. pattern layout example the following show the pcb pattern layout example and the schematic of circuit using STR3A100 series. only the parts in the schematic are used. other parts in pcb are leav ed open. figure 11 - 1 pcb circuit trace layout example figure 11 - 2 circuit schematic for pcb circuit trace layout the above circuit symbols correspond to these of figure 11 - 1 . j 1 c 3 t 1 d 51 r 52 u 51 d p 1 s 1 pc 1 l 51 gnd c 52 r 53 f 1 1 3 c 1 th 1 l 1 nc 1 2 4 d / st d / st vcc s / ocp fb / olp d / st 8 7 5 str 3 a 100 u 1 gnd 3 out 2 gnd vout 1 c 4 c 6 c 5 c 8 c 9 d 2 d 3 d 4 d 1 d 5 d 6 r 2 r 3 r 1 d 52 c 51 c 53 c 54 r 51 r 54 r 55 r 56 r 57 r 58 r 59 r 60 r 61 jw 51 jw 52 pc 1 c 56 c 57 cn 52 r 5 c 2 c 10 c 11 r 4 d / st 6 r 63 r 62 l 52 c 55 jw 53 c 7 cn 51
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 22 jan. 28 , 2 01 4 12. reference design of power supply as an example, the following show the power supply specification, the circuit schematic, the bill of mate rials, and the transformer specification. ? power supply specification ic str 3a 1 53 input voltage ac85v to ac265v maximum output power 40.4 w (peak) output 1 8 v / 0.5 a output 2 14 v / 2.3 a (2.6 a peak) ? circuit schematic refer to figure 11 - 2 ? bill of materials symbol part type ratings (1) recommended sanken parts symbol part type ratings (1) recommended sanken parts f1 fuse ac 250 v, 3 a l51 inductor short l1 (2) cm inductor 3.3 mh l52 inductor short th1 (2) ntc thermistor short d51 schottky 90 v, 1.5 a ek19 d1 general 600 v, 1 a em01a d52 schottky 150v, 10a fmen - 210b d2 general 600 v, 1 a em01a c51 (2) electrolytic 470 f, 25 v d3 general 600 v, 1 a em01a c52 (2) ceramic 0.1 f, 50 v d4 general 600 v, 1 a em01a c53 (2) electrolytic open d5 fast re covery 1000 v, 0.5 a eg01c c54 electrolytic d6 fast re covery 200 v, 1 a al01z c55 (2) electrolytic open c1 (2) film, x2 0.047 f, 275 v c56 (2) ceramic open c2 (2) elec trolytic open c57 (2) ceramic open c3 electro lytic 10 f, 400 v r51 general open c4 ceramic 1000 pf, 2 kv r52 general 1.5 k c5 electrolytic 22 f, 50 v r53 (2) general 100 k c6 (2) cera mic 0.01 f r54 general, 1% open c7 (2) ceramic open r55 general, 1% open c8 (2) ceramic 15 pf / 2 kv r56 general, 1% 10 k c9 ceramic, y1 2200 pf, 250 v r57 general open c10 (2) cer amic open r58 general 2.2 k c11 (2) cer amic open r59 (2) general 6.8 k r1 (3) metal oxide 150 k, 2 w r60 general, 1% 39 k r2 (2) gene ral 10 r61 general open r3 (2) gene ral 0.47 , 1/2 w r62 (2) general open r4 (2) gene ral short r63 (2) general open r5 (3) metal oxide open jw51 short pc1 photo - coupler pc123 or equiv jw52 short u1 ic st r 3a 1 53 jw53 short t1 transfo rmer see the specification u51 shunt regulator v ref = 2.5 v tl431 or equiv (1) unless othe rwise specified, the voltage rating of capacitor is 50 v or less and the power rating of resistor is 1/8 w or less. (2) it is necessary to be adjusted based on actual operation in the application. (3) resistors applied high dc voltage and of high resistance are re commended to select resistors designed against electromigration or use combinations of resistors in series for that to reduce each applied voltage, according to the requirement of the application.
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 23 jan. 28 , 2 01 4 ? transformer specification ? primary inductance, l p 518 h ? core size eer - 28 ? al - value 245 nh/n 2 (center gap of about 0. 56 mm ) ? winding specification winding symbol number of turns (t) wire diameter (mm) construction primary winding p1 18 0.23 2 0.30 0.30 2 0.4 2 0.4 2 0.4 2 0.4 2 b o b b i n d s 1 - 1 p 1 v c c g n d 8 v c o r e p 2 p 2 s 2 - 1 1 4 v g n d s 1 - 1 d p 1 s 2 - 2 v d c d r a i n m a r g i n t a p e 2 m m 4 m m m a r g i n t a p e p i n s i d e s 1 - 2 s 1 - 2 s 2 - 1 s 2 - 2 c r o s s - s e c t i o n v i e w : s t a r t a t t h i s p i n
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 24 jan. 28 , 2 01 4 operating precautions in the case that you use sanken products or design your products by using sanken products, the reliability largely depends on the degree of derating to be made to the rated values. derating may be interpreted as a case that an operation range is set by derating the load from each rated value or surge voltage or noise is considered for derating in order to assure or improve the reliab ility. in general, derating factors include electric stresses such as electric voltage, electric current, electric power etc., environmental stresses such as ambient temperature, humidity etc. and thermal stress caused due to self - heating of semiconductor products. for these stresses, instantaneous values, maximum values and minimum values must be taken into consideration. in addition, it should be noted that since power devices or ics including power devices have large self - heating value, the degree of de rating of junction temperature affects the reliability significantly. because reliability can be affected adversely by improper storage environments and handling methods, please observe the following cautions. cautions for storage ? ensure that storage conditions comply with the standard temperature (5 to 35c) and the standard relative humidity (around 40 to 75%); avoid storage locations that experience extreme changes in temperature or humidity. ? avoid locations where dust or harmful gases are present a nd avoid direct sunlight. ? reinspect for rust on leads and solderability of the products that have been stored for a long time. cautions for testing and handling when tests are carried out during inspection testing and other standard test periods, protect the products from power surges from the testing device, shorts between the product pins, and wrong connections. ensure all test parameters are within the ratings specified by sanken for the products. remarks about using silicone grease with a heatsink ? when silicone grease is used in mounting the products on a heatsink, it shall be applied evenly and thinly. if more silicone grease than required is applied, it may produce excess stress. ? volatile - type silicone greases may crack after long periods of time, res ulting in reduced heat radiation effect. silicone greases with low consistency (hard grease) may cause cracks in the mold resin when screwing the products to a heatsink. our recommended silicone greases for heat radiation purposes, which will not cause any adverse effect on the product life, are indicated below: type suppliers g746 shin - etsu chemical co., ltd. yg6260 momentive performance materials inc. sc102 dow corning toray co., ltd. soldering ? when soldering the products, please be sure to minimize the working time, within the following limits: ? 260 5 c 10 1 s (flow, 2 times) ? 380 10 c 3.5 0.5 s (soldering iron, 1 time) ? soldering should be at a distance of at least 1.5 m m from the body of the products. electrostatic discharge ? when handling the products, the operator must be grounded. grounded wrist straps worn should have at least 1m of resistance from the operator to ground to prevent shock hazard, and it should be placed near the operator. ? workbenches where the products are handled should be grounded and be provided with conductive table and floor mats. ? when using measuring equipment such as a curve tracer, the equipment should be grounded. ? when soldering the products, the head of soldering irons or the solder bath must be grounded in orde r to prevent leak voltages generated by them from being applied to the products. ? the products should always be stored and transported in sanken shipping containers or conductive containers, or be wrapped in aluminum foil.
STR3A100 series STR3A100 - ds rev .1.31 sanken electric co.,ltd. 25 jan. 28 , 2 01 4 important notes ? the contents in this document are subject to changes, for improvement and other purposes, without notice. make sure that this is the latest revision of the document before use. ? application and operation examples described in this document are quoted for the sole purpose of reference for the use of the products herein and sanken can assume no responsibility for any infringement of industrial property rights, intellectual property rights or any other rights of sanken or any third party which may result from its use. unless otherwise agreed in writing by sanken, sanken makes no warranties of any kind, whether express or implied, as to the products, including product merchantability, and fitness for a particular purpose and special environment, and the information, including i ts accuracy, usefulness, and reliability, included in this document. ? although sanken undertakes to enhance the quality and reliability of its products, the occurrence of failure and defect of semiconductor products at a certain rate is inevitable. users of sanken products are requested to take, at their own risk, preventative measures including safety design of the equipment or systems against any possible injury, death, fires or damages to the society due to device failure or malfunction. ? sanken products l isted in this document are designed and intended for the use as components in general purpose electronic equipment or apparatus (home appliances, office equipment, telecommunication equipment, measuring equipment, etc.). when considering the use of sanken products in the applications where higher reliability is required (transportation equipment and its control systems, traffic signal control systems or equipment, fire/crime alarm systems, various safety devices, etc.), and whenever long life expectancy is required even in general purpose electronic equipment or apparatus, please contact your nearest sanken sales representative to discuss, prior to the use of the products herein. the use of sanken products without the written consent of sanken in the applic ations where extremely high reliability is required (aerospace equipment, nuclear power control systems, life support systems, etc.) is strictly prohibited. ? when using the products specified herein by either (i) combining other products or materials therew ith or (ii) physically, chemically or otherwise processing or treating the products, please duly consider all possible risks that may result from all such uses in advance and proceed therewith at your own responsibility. ? anti radioactive ray design is not considered for the products listed herein. ? sanken assumes no responsibility for any troubles, such as dropping products caused during transportation out of sankens distribution network. ? the contents in this document must not be transcribed or copied witho ut sankens written consent.

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