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contents features............................................................. 1 applications........................................................ 1 block diagram.................................................... 1 pin assignment .................................................. 2 absolute maximum ratings ............................... 2 electrical characteristics.................................... 2 test circuits ....................................................... 3 operation timing chart...................................... 4 dimensions ........................................................ 4 markings ............................................................ 4 taping ................................................................ 5 operation ........................................................... 6 selection of external parts................................. 10 standard circuits ............................................... 12 merits in designing ............................................ 13 notes on design ................................................ 13 application circuits ............................................ 14 characteristics ................................................... 15
seiko instruments inc. 1 step up & down voltage regulator s-8430af the s-8430af is a chopper-type dc/dc converter made using the cmos process. it automatically steps the voltage up and down according to the input voltage. when the input voltage is higher than the output voltage, the s-8430af operates as a series regulator. when the input voltage is lower than the output voltage, it operates as a combination of a step-up switching regulator and a series regulator. the output voltage for normal operation can be selected from either 5 v or 3 v and the output level during shutdown can be selected from either the v ss level or the input voltage level. * parasitic diode * on/off m2 features low current consumption operation : 11 m a typ. shutdown : 0.2 m a max. low voltage operation: 0.9 v min. output voltage: 5 v or 3 v high precision output voltage: 5 v 4% or 3 v 5% shutdown function output voltage during shutdown: @ v ss or @ input voltage built-in cr oscillation circuit oscillating frequency: 40 khz typ. few external parts because of built-in schottky diode 8-pin sop package block diagram applications camera pager handy copier handy terminal other battery-driven equipment v sw cont v out sel1 sel2 v ss m1 cr oscillation circuit - + v in ref. voltage circuit control circuit - + figure 1
step up & down voltage regulator s-8430af 2 seiko instruments inc. pin assignment absolute maximum ratings electrical characteristics no. name description 2 on/off shutdown h: normal operation l: shutdown 3 sel1 selects output voltage during shutdown h: v out @ v in , l: v out @ v ss 4 sel2 selects normal operation output voltage h: v out =5 v, l: v out =3 v 7 cont output driver for external inductor 5v out output voltage 6v sw switching regulator output 1v in positive power supply input 8v ss gnd parameter symbol conditions ratings unit input voltage v in 12 v output voltage of switching regulator v sw v ss -0.3 to 12 v output voltage v out v ss -0.3 to v sw +0.3 v input pin voltage on/off, sel1, sel2, cont v ss -0.3 to 12 v power dissipation p d 300 mw operating temperature t opr -30 to +80 c storage temperature t stg -40 to +125 c parameter symbol conditions min. typ. max. unit test circuit input voltage v in ?? 10.0 v 1 output voltage* v out1 v in =2 v, i out =30 ma sel2=l, on/off=h 2.85 3.00 3.15 v 1 v out2 v in =3 v, i out =30 ma sel2=on/off=h 4.80 5.00 5.20 v 1 current consumption i ss v in =3 v, unloaded, sel1=sel2=on/off=h ? 11 25 m a2 shutdown current i sss1 v in =7 v, unloaded sel1=sel2=h, on/off=l ?? 2.0 m a3 i sss2 v in =7 v, unloaded sel1=l, sel2=h, on/off=l ?? 0.2 m a3 oscillating frequency f osc v in =3 v 20 40 70 khz 4 line regulation d v out d v in v ou v in =3 to 10 v, i out =30 ma, sel2=h ? 0.1 0.2 %/v 1 v in =2 to 10 v, i out =30 ma, sel2=l ? 0.1 0.2 %/v 1 load regulation d v out v in =3 v, i out =50 m a to 30 ma, sel2=h ? 20 80 mv 1 v in =2 v, i out =50 m a to 30 ma, sel2=l ? 20 80 mv 1 temperature coefficient of v out d v out d ta ta=-30 c to 80 c, sel2=h or l ? 0.38 ? mv/ c ? switching current i sw v ds =0.2 v, sel2=h ? 250 ? ma ? leakage current of switching transistor i swq v ds =10 v ?? 1.0 m a 6 input voltage for on/off, sel1, and sel2 pins v sh v in =3 v, h level 2.4 ?? v5 v sl v in =3 v, l level ?? 0.4 v 5 output voltage during shutdown v sout1 v in =v sw =7 v, unloaded on/off=l, sel2=h sel1=l 0 ? 0.1 v 5 v sout2 sel1=h 6.9 ? 7.0 v 5 oscillation duty ratio f d v in =3 v ? 50 ? % ? operation start voltage v st v out 3 2 v, unloaded, sel2=l 0.9 ?? v1 figure 2 v in on/off sel1 sel2 6 5 8 7 3 4 1 2 v ss cont v sw v out 8-pin sop top view table 1 (unless otherwise specified : ta=25 c) table 2 (unless otherwise specified : ta=25 c ) * external parts: coil: fl5h101k (100 m h) manufactured by taiyo yuden, or equivalent diode: d1ns4 manufactured by shindengen, or equivalent
step up & down voltage regulator s-8430af seiko instruments inc. 3 test circuits a v a 4. oscillo- scope 200 w v in v ss v ss v in v in i 1 c out (22 m f) 100 m h i 2 100 m h 10 v 10 v cont v 2 v out v in cont v sw v ss on/off sel1 sel2 ?? v 1. v in cont v ss on/off sel1 sel2 3. v in v ss on/off sel1 sel2 2. a v sw v ss on/off sel1 sel2 v sw on/off sel1 sel2 5. v sw v out 7 v cont on/off sel1 sel2 6. v sw c sw (22 m f) apply 3 v to v 1 and 5 v to v 2 and measure i 1 apply 3 v to v 1 and 7 v to v 2 and measure i 2 i s =i 1 +i 2 a figure 3 + - v 1 + -
step up & down voltage regulator s-8430af 4 seiko instruments inc. operation timing chart dimensions markings t t t t l l l 0v v out2 h h h 10 v 2 v v in 10 v 2 v v out1 sel2 sel1 on/off v out figure 4 t 1.27 0 min. 0.4 0.1 1.5 0.1 1.7max. 0.15 +0.1 - 0.05 0.4 4.4 4 5 8 1 5.2 (5.5 max.) 6.2 0.3 unit : mm figure 5 1 to 7 :product name 8 :assembly code 9 :year of assembly (last digit) 10 :month of assembly; jan.=1, feb.=2, mar.=3, apr.=4, may=5, june=6, july=7, aug.=8, sept.=9, oct.=x, nov.=y, dec.=z 11 to 13 :lot no. 1 2 3 45 6 7 8 9 10 11 12 13 figure 6
step up & down voltage regulator s-8430af seiko instruments inc. 5 taping 1. tape specifications t1 and t2 types are available depending upon the direction of ics on the tape. 2. reel specifcations 1 reel holds 2000 regulators. 1.75 0.1 5.55 0.1 12.0 0.2 f 2.0 0.050 0.3 0.05 feed direction feed direction t1 t2 5.5 0.05 f 1.55 0.05 8.0 0.1 6.70 0.1 2.0 0.05 2.10 0.1 3 max. 4.0 0.1(10 pitches : 40.0 0.2) 5 max. figure 7 unit : mm figure 8
step up & down voltage regulator s-8430af 6 seiko instruments inc. operation the s-8430af consists of a switching regulator, a series regulator, and a controller circuit. the switching regulator is casca ded with the series regulator. control pin input operation of each circuit block and output status on/off* sel1* sel2* switching regulator v sw regulation circuit series regulator output voltage v out current consumption h ? h operate 6.25 v 4% 5 v 5 v 4% 25 m a max. ? l operate 4.21 v 7% 3 v 3 v 5% 25 m a max. lh ? stop @ v in ** stop @ v in *** 2.0 m a max. l ? stop @ v in ** stop @ v ss 0.2 m a max. * do not use control pins in floating status, otherwise the ouput voltage will be unstable. ** input voltage minus the sum of the voltage reduction due to dc resistance of the inductor and the forward voltage reduction of the diode. *** input voltage minus the sum of the voltage reduction due to dc resistance of the inductor, the forward voltage detection of the diode and the voltage reduction of the m2 transistor. 1. control circuit the s-8430af has three control pins (on/off, sel1, and sel2) that meet the ttl level. these pins control internal circuits. table 3 shows the statuses and output levels of the control pins. table 3 ? : invalid 8 10 11 12 9 7 6 5 4 3 vdif (mv) 2 1 20.00 30.00 40.00 10.00 0 ta=25 c figure 9 input/output voltage difference of transistor m2 i out =100 m a i out =500 m a i out =1000 m a v sw (v) the on/off pin controls the operation of the s-8430af. the s-8430af operates while the on/off pin is high, and it ? s in shutdown status while it is low. during shutdown, internal circuits such as the oscillation circuit, the error amplifier, the reference voltage circuit, and the logic circuit stop and current consumption drops drastically. the sel1 pin is enabled only during shutdown. its output statuses are as described below: if the sel1 pin is low, the vss level is output. if the sel1 pin is high, the voltage obtained by subtracting the sum of the voltage reduction due to dc resistance of the inductor, the forward voltage reduction of the diode and the voltage reduction of the transistor m2 from the input voltage is output. the sel2 pin is enabled only during operation. its output voltages are as follows: if the sel2 pin is low, 3.0 v 5% is output. if the sel2 pin is high, 5.0 v 4% is output.
step up & down voltage regulator s-8430af seiko instruments inc. 7 2. switching regulator 3. series regulator a series regulator installed in the s-8430af regulates v sw voltage and outputs in v out . the output level allows selection of 5 v or 3 v according to the level of the sel2 pin (see table 3). the control transistor (m2) for the series regulator is a pch mos transistor with a large k value. this allows generation of large output current with only a small difference between input and output voltages. 4. step-up/down operation with switching regulator and series regulator 4.1 when v in step up & down voltage regulator s-8430af 8 seiko instruments inc. 4.2 when v in >v sw when the v sw voltage [v in -(v l +v d )] exceeds the adjusted voltage value, only the series regulator works to stabilize the input voltage. 5. reference: basic formula for the switching regulator c sw =c out =22 m f, i out =30 ma, v in =3 v v pp (mv) -40 -20 0 20 40 60 80 100 ta ( c) 0 figure 12 200 400 600 800 1000 (1) v sw output c sw =c out =22 m f, i out =30 ma, v in =3 v -40 -20 0 20 40 60 80 100 ta ( c) 0 50 150 200 sel2= h sel2= h v pp (mv) (2) v out output figure 13 100 the voltage at a at the instant that m1 is turned on (the current (i l ) flowing in l is zero): v a =v s .............................. (1) (v s : non-saturation voltage of m1) change of i l in time: i l v l v in - v s = = ..................................... (2) dt l l integration (i l ) of the above formula: v in - v s i l = t ..................................(3) l i l flows during t on , which is determined by the oscillation frequency of osc. the peak current (i pk ) after t on : v in - v s i pk = t on ................. (4) l the energy accumulated in l at that time is expressed by 1/2 l(i pk ) 2 . the next time m1 is turned off (t off ), the energy stored in l is released through the diode (di), causing a reverse voltage (v l ). v l is expressed by: v l =(v out +v d ) - v in .................... (5) (v d : forward voltage of diode di) the voltage at a rises only as much as the sum of v out +v d . this section describes the basic formulas (( 1 ) to ( 7 )) for the step-up switchin g re g ulator. change of current (i l ) that flows to v out through the diode during t off in time: : i l v l v out +v d - v in = = ...................... (6) d t l l integration of the above formula: v out + v d - v in i l =i pk - t ............................(7) l
step up & down voltage regulator s-8430af seiko instruments inc. 9 (i pk -i out ) t 1 = during t on , energy is accumulated in l and is not transferred to v out . to obtain a load current (i out ) from v out , the energy in the capacitor (c sw ) is used. as a result, the pin voltage of c sw is lowered (to the minimum after t on ). when m1 is turned off, the energy accumulated in l is transferred to c sw through the diode, rapidly increasing the c sw pin voltage. since v out is a time function, v out reaches the maximum value (ripple voltage: v pp ) when the current flowing to v out through the diode matches the constant load current i out . the following describes how to calculate the ripple voltage. i out , when the time between t on and the highest level of v out is expressed as t 1 : \ i out =i pk - v out +v d - v in l t 1 t 1 =(i pk -i out ) v out +v d - v in l based on (7), since i l =0 (all the energy inthe in ductor is released during t off ) : v out +v d - v in l = i pk t off substituting (9) with (10) : t 1 =t off - i pk i out the amount of electric charge d q1 accumulated in c sw during t 1 is: d q 1 = t 1 0 i l dt=i pk dt - v out +v d -v in l t 1 0 t dt =i pk t 1 - v out +v d -v in l 2 1 t 1 2 substituting (9) with (12): d q 1 =i pk - 2 1 2 i pk +i out t 1 the voltage (v pp ) raised by d q 1 is: v pp = c sw d q 1 = c sw 1 2 i pk +i out t 1 taking i out consumed duirng t 1 into consideration: v pp = c sw d q 1 = c sw 1 2 i pk +i out t 1 - c sw i out t 1 substituting formula (15) with formula (11): 2i pk (i pk - i out ) 2 v pp = c sw t off t off t 1 0 ................................ (16) ........................... (15) ................................ (14) ........................... (13) ............................ (12) ................................ (11) ................................ (10) ................................ (9) ................................ (8)
step up & down voltage regulator s-8430af 10 seiko instruments inc. selection of external parts 1. inductor to reduce the loss due to the dc resistance, select an inductor with as small an dc resistance as possible (less than 1 w ). select the best inductance for the application. to make the average value of the output voltage (v out ) constant, the inductor must supply energy equivalent to the output current (i out ). the amount of charge required for i out is i out (t on +t off ). the inductor can supply energy only during t off , thus the amount of charge is obtained as i pk /2 t off by integrating formula (7) by 0 ? t off . therefore: since the oscillation duty ratio of the osc is 50% and i pk equals 4 i out if t on =t off , the i pk current flowing in the transistor must be four times as much as the required i out . i pk is limited due to the characteristics of the m1 transistor (500 ma max.). in the s-8430af, recommended inductance is between 30 and 270 m h. using an inductor with a large l value decreases i pk and i out . since the energy accumulated in the inductor is 1/2 l(i pk ) 2 , i pk decreases in steps of squares offsetting the increase of l, and the energy decreases overall. accordingly, stepping up at low voltages is difficult and the lowest operating voltage must be specified as a high value. however, the dc resistance loss in l and the m1 transistor becomes small because of the reduced i pk , and the efficiency is improved overall. using an inductor with a small l value increases i pk and i out . accordingly, the minimum operating voltage is lowered, but efficiency decreases. note too large i pk causes magnetic saturation for some core materials, resulting in destruction of the ic chip. always keep i sat higher than i pk (i sat : level of current that causes magnetic saturation). for reference, table 4 shows the change of drivability due to differences in inductors, measured using output current i out as a parameter. table 4 product name manufacture l value dc resistance ref. fl5h470k taiyo yuden 47 m h 1.37 w a fl5h101k taiyo yuden 100 m h 2.02 w b fl5h27ak taiyo yuden 270 m h 4.84 w c ? (custom made) 47 m h 0.37 w d nlc453232 tdk 47 m h 1.45 w e 2 i pk ..................................... (18) ..................................... (17) t off =i out (t on +t off ) \ i pk =2 t on +t off t off i out 0 2 4 6 8 10 0 2 4 6 8 10 output voltage (v) input voltage (v) v out =3 v a condition: i out =10, 30, 50, 70, 100 (ma), ta=25 c 10 ma v out =5 v 100 ma input voltage (v) output voltage (v) 5.3 5.2 5.1 5.0 4.9 4.8 4.7 3.2 3.1 3.0 2.9 2.8 2.7 3.3
step up & down voltage regulator s-8430af seiko instruments inc. 11 10 0 2 4 6 8 0 2 4 6 8 10 v out =5 v v out =3 v b input volta g e ( v ) input volta g e ( v ) output voltage (v) output voltage (v) 5.3 5.2 5.1 5.0 4.9 4.8 4.7 3.2 3.1 3.0 2.9 2.8 2.7 3.3 0 2 4 6 8 10 0 2 4 6 8 10 0 2 4 6 8 10 0 2 4 6 8 10 0 2 4 6 8 10 0 2 4 6 8 10 v out =5 v d v out =3 v v out =3 v v out =5 v v out =5 v v out =3 v e c condition: i out =10, 30, 50, 70, 100 (ma), ta=25 c 10 ma 100 ma output voltage (v) input volta g e ( v ) input volta g e ( v ) input volta g e ( v ) input volta g e ( v ) input volta g e ( v ) input volta g e ( v ) output voltage (v) output voltage (v) output voltage (v) output voltage (v) output voltage (v) 5.3 5.2 5.1 5.0 4.9 4.8 4.7 3.2 3.1 3.0 2.9 2.8 2.7 5.3 5.2 5.1 5.0 4.9 4.8 4.7 5.3 5.2 5.1 5.0 4.9 4.8 4.7 3.2 3.1 3.0 2.9 2.8 2.7 3.2 3.1 3.0 2.9 2.8 2.7 note input voltage is measured by 0.5 v step. graphs from a to e have a few measurement errors. 3.3 3.3 3.3
step up & down voltage regulator s-8430af 12 seiko instruments inc. 2. diode the s-8430af has a built-in schottky diode, which has almost the same performance as the 1s1588 small signal diode (manufactured by shindengen). figure 14 shows the efficiency difference in the temperature characteristics between the d1ns4 and the built-in schottky diode. the efficiency of the built-in schottky diode is less than that of the d1ns4 by about 7%. to improve the efficiency to obtain over 10 ma of output current, use an external schottky diode that has the following characteristics: low forward voltage fast switching rate (500 ns or less. in particular, the recovery time must be short.) high backward dielectric strength (low backward leakage current) 3. rectifying capacitor (c sw ) add a large capacity of capacitor such as an electrolytic capacitor as c sw to the v sw pin. in general, the capacitance of electrolytic capacitors decreases due to low temperature with ripple voltage increasing as a result. ripple voltage is inverse ly proportional to the capacitance of rectifying capacitors and to the switching frequency, and is proportional to peak current i pk . select a capacitor of higher dielectric strength than the values described below as a rectifying capacitor to attenuate the ripple voltage. when sel is h: v sw voltage=6.5 v max. + ripple voltage when sel is l: v sw voltage=4.5 v max. + ripple voltage you can also use a tantalum electrolytic capacitor or an o.s. capacitor, which is superior to an aluminum electrolytic capacitor in low-temperature characteristics and leakage current characteristics. standard circuits 1. when the built-in schottky diode is used and the output is 5 v 20 15 -40 -20 0 20 40 60 80 100 5 - 60 120 efficiency difference (%) ta ( c) sel2=h v in =3 v i out =30 ma 0 figure 14 10 + l (30 to 270 m h) v out v in cont v sw v ss on/off - + + - - v out sel sel s -8430af c out (22 m f) c sw (22 m f) c in (47 m f) figure 15
step up & down voltage regulator s-8430af seiko instruments inc. 13 2. when an external schottky diode is used and the output is 5 v merits in designing notes on design in applications where the output current is less than 10 m a, the output current may rise due to the leak current of the control transistor. this may cause the load stability to be out of the standard. keep the output current more than 10 m a. install external capacitors, diodes, and coils as close as possible to the ic chip. the switching regulator causes unique ripple voltages and spike noises. to implement a design using the s-8430af, evaluate the performance with the actual device. consider the tolerable loss of the switching transistor, particularly at high temperature. l (30 to 270 m h) di v out v sw cont v in v ss on/off - + + - - + v out sel sel s -8430af c out (22 m f) c sw c in (47 m f) (22 m f) figure 16 battery voltage (v) when a series re g ulator is used t 1 t 2 when the s-8430af is used in a power supply circuit of low current consumption that generates about 30 ma of output current, you can structure a system that effectively uses the battery. the reason for this is as follows: the output voltage is constant, regardless of the input voltage. this prolongs the operating time (t 1 ? t 2 ). if the input voltage becomes higher than the output voltage, the oscillation circuit of the switching regulator automatically stops. this reduces power consumption. operating time when the s-8430af is used figure 17 ambient temperature ta ( c) 0 300 110 25 power dissipation p d (mw) fi g ure 18 power dissi p ation of 8- p in sop
step up & down voltage regulator s-8430af 14 seiko instruments inc. application circuits 1. a power changeover system of 3 v and 5 v (1) the fall of input voltage makes automatically the output of the s-8430af 3 v, and at the same time a microcomputer enters standby mode. (2) a current consumption reducing system when operating a 5-v operating microcomputer with 3-v battery, a voltage detector is used to monitor the battery voltage. if the voltage detector detects the fall of the battery voltage, the s-8430af turns off to save current consumption. also, unregulated @ v in voltage is output to v out pin. therefore, the sram data can be kept in backup system. 2. when boosting output current installing an external bipolar transistor increases the output current. however, efficiency decreases as all base current is consumed. + figure 19 v ss on/off v dd v out v sw cont v in sel sel s -8430af micro- computer ce voltage detector + - + - + - figure 20 v ss on/off v dd v out v sw cont v in sel sel s -8430af micro- computer ce voltage detector 3 v + - + - + - + - v ss - + cont v in v sw - figure 21 s -8430af v out
step up & down voltage regulator s-8430af seiko instruments inc. 15 characteristics 1. operating current consumption (i ss ) - ambient temperature (ta) 0.7 7 v sh , v sl (v) on/off=sel1= sel2=h on/off=sel1=h, sel2=l i ss ( m a) 20 15 10 5 0 - 4 0 - 20 0 2 0 40 60 80 100 ta ( c) i ss ( m a) 20 15 10 5 0 - 4 0 - 20 0 2 0 40 60 80 100 ta ( c) 1.1 v in =3 v 1.2 v in =2 v 40 i sss2 ( m a) i sss1 ( m a) - 4 0 - 20 0 2 0 60 80 100 ta ( c) v in =7 v , on/off=l , sel1=sel2=h 5 4 3 2 1 0 6 - 4 0 - 20 0 2 0 40 60 80 100 ta ( c) 0.5 0.4 0.3 0.2 0.1 0 0.6 v in =7 v , on/off=sel1=l , sel2=h * i sss1 and i sss2 increase with hi g h temperature. 2. shutdown current (i sss1 ) - ambient temperature (ta) 3. shutdown current (i sss2 ) - ambient temperature (ta) (%/v) d v in v out d v out - 20 ta ( c) 0 20 40 - 40 60 80 100 0.00 0.02 0.04 0.06 0.08 0.10 4. line regulation -ambient temperature (ta) sel2= h , i out =30 ma d v in v out d v out - 20 ta ( c) 0 20 40 - 40 60 80 100 0.00 10.0 30.0 20.0 d v out (mv) sel2= h , v in =3 v, v out =5 v 5. load regulation ( d v out ) -ambient temperature (ta) - 20 ta ( c) 0 20 40 - 40 60 80 100 0.0 0.2 0.6 0.8 6. oscillation start voltage (v osc ) - ambient temperature (ta) v osc (v) 2 3 4 5 1 6 7 8 0.00 0.50 1.50 2.00 2.50 1.00 9 10 v in (v) 7. input voltage of on/off, sel1 & sel2 pin (v sh , v sl ) - input voltage (v in ) 3.00 v sl v sh 0.4 v sh : lowest voltage recognized as high v sl : hi g hest volta g e reco g nized as low 1.0
step up & down voltage regulator s-8430af 16 seiko instruments inc. 8. v in step response 8.1 sel2=h, v in =0 v ? 3 v 8.2 sel2=h, v in =0 v ? 10 v 8.3 sel2=l, v in =0 v ? 2 v 8.4 sel2=l, v in =0 v ? 10 v c sw =c out =22 m f, r l =166 w , v out =5 v, ta=25 c t (ms) 5 v input volta g e 0 v output voltage ( 1 v/div ) 10 v c sw =c out =22 m f, r l =166 w , v out =5 v, ta=25 c t (ms) input voltage 0 v output voltage (1 v/div) note use a capacitor in due consideration of overshooting value to the v sw and v out pins, as a ringing occurs in the waveform during the fluctuations of input voltage and output current. c sw =c out =22 m f, r l =166 w , v out =3 v, ta=25 c t (ms) 5 v input voltage 0 v output voltage ( 1v/div ) c sw =c out =22 m f, r l =166 w , v out =3 v, ta=25 c t (ms) 10 v input voltage 0 v output voltage ( 1 v/div )
step up & down voltage regulator s-8430af seiko instruments inc. 17 8.5 sel2=h, v in =3 v ? 10 v 8.6 sel2=l, v in =2 v ? 10 v 9. output current (load current) fluctuation response (b) v in =7 v c sw =c out =22 m f, r l =166 w , v out =5 v, ta=25 c input voltage output voltage ( 0.2 v/div ) t (2 ms/div) 10 v 0 v note when a voltage detector (s-807 series of seiko instuments inc.) is connected externally to v out pin, use one in due consideration of undershootin g value. c sw =c out =22 m f, r l =166 w , v out =3 v, ta=25 c t (2 ms/div) 0 v output voltage ( 0.2 v/div ) 10 v input volta g e c sw =c out =22 m f, ta=25 c t (2 ms/div) output voltage (0.2 v/div) 2ma 30 ma 9.1 i out =2 ma ? 30 ma on/off=sel1=sel2=h ( a ) v in =3 v output current c sw =c out =22 m f, ta=25 c output voltage (0.2 v/div) t (2 ms/div) 2ma 30 ma output current
step up & down voltage regulator s-8430af 18 seiko instruments inc. (b) v in =5 v note if an output current fluctuates in larger scale than the graphs above, larger ringing occurs. c sw =c out =22 m f, ta=25 c t (2 ms/div) output voltage (0.1 v/div) 1 ma 18 ma 9.2 iout=1 ma ? 18 ma on/off=sel1=h, sel2=h (a) v in =2 v output current c sw =c out =22 m f, ta=25 c 18 ma 1 ma output voltage (0.1 v/div) t (2 ms/div) output current 10. on/off pin response 10.1 v in =3 v, sel1=h, sel2=h c sw =c out =22 m f, r l =166 w , ta=25 c t (2 ms/div) 5 v 0 v output voltage (0.5 v/div) on/off input voltage c sw =c out =22 m f, r l =166 w , ta=25 c t (2 ms/div) 5v 0 v output voltage ( 0.5 v/div ) on/off input voltage 10.2 v in =3 v, sel1=l, sel2=h
step up & down voltage regulator s-8430af seiko instruments inc. 19 10.3 v in =3 v, sel1=h, sel2=l 10.4 v in =3 v, sel1=l, sel2=l 10.5 v in =7 v, sel1=h, sel2=h 10.6 v in =7 v, sel1=l, sel2=h t (2 ms/div) c sw =c out =22 m f, r l =166 w , ta=25 c 5 v 0 v output voltage ( 0.5 v/div ) on/off input voltage t (2 ms / div) c sw =c out =22 m f, r l =166 w , ta=25 c 5 v 0 v output voltage (0.5 v/div) on/off input voltage t (2 ms / div) c sw =c out =22 m f, r l =166 w , ta=25 c 5 v 0 v output voltage ( 0.5 v/div ) on/off input voltage t (2 ms/div) c sw =c out =22 m f, r l =166 w , ta=25 c 5 v 0 v output voltage ( 1 v/div ) on/off input voltage
step up & down voltage regulator s-8430af 20 seiko instruments inc. 10.7 v in =7 v, sel1=h, sel2=l 10.8 v in =7 v, sel1=l, sel2=l 11. sel1 pin response c sw =c out =22 m f, r l =166 w , ta=25 c 5v 0 v t (1 ms / div) on/off input voltage output voltage ( 0.5 v/div ) c sw =c out =22 m f, r l =166 w , ta=25 c 5 v 0 v output voltage ( 0.5 v/div ) t (1 ms/div) on/off input voltage c sw =c out =22 m f, r l =166 w , ta=25 c 5 v sel1 input voltage 0 v output voltage (1 v/div) t (5 ms/div) 11.1 v in =3 v, on/off=l, sel2=h c sw =c out =22 m f, r l =166 w , ta=25 c 5 v sel1 input voltage 0 v output voltage (1 v/div) t (5 ms/div) 11.2 v in =3 v, on/off=l, sel2=h
step up & down voltage regulator s-8430af seiko instruments inc. 21 12. sel2 pin response 13. efficiency- temperature (in case of using l=100 m h (fl5h101k), di : d1ns4) 14. oscillating frequency 14.1 input voltage (v in ) 14.2 temperature (ta) c sw =c out =22 m f, r l =166 w , ta=25 c 5 v sel2 input volta g e 0 v output voltage (0.5 v/div) t (2 ms/div) 12.1 v in =3 v, on/off=h, sel1=h h (%) - 20 ta ( c) 0 20 40 - 40 60 80 100 0 20 40 60 80 100 h (%) - 20 ta ( c) 0 20 40 - 40 60 80 100 0 20 40 60 80 100 v in =3 v, i out =30 ma, sel2= h v in =3 v, i out =30 ma, sel2= h 13.1 v sw pin (output of switching regulator) 13.2 v out pin (output of whole ic) note: the efficiency is fluctuated by an inductor of diode. and the total efficiency falls for series regulator. v in =3 v - 20 ta ( c) 0 20 40 - 40 60 80 100 0 10 40 50 0.00 0.40 0.60 0.20 0.80 1.00 1.20 1.40 v in (v) f (khz) 0 1 2 3 4 5 6 7 8 9 10 11 12 30 20 regulation at v in =3 v ta=25 c c sw =c out =22 m f, r l =166 w , ta=25 c 5v sel2 input voltage 0v output voltage (0.5 v/div) t (2 ms/div) 12.2 v in =7 v, on/off=h, sel1=h
step up & down voltage regulator s-8430af 22 seiko instruments inc. 15.output voltage of the switching regulator (v sw ) - temperature 16. output voltage (v out ) - ambient temperature (ta) 16.1 v out =3 v 16.2 v out =5 v 17. output current in the minimum input voltage (i out ) - output voltage (v out ) 18. rising/falling time of switching transistor (m1) based on the v sw volta g e at 25 c 10 0 -10 -20 -50 -4 0 -20 0 2 0 40 60 80 100 ta ( c ) -30 d v sw (mv) -40 - 20 0 20 40 - 40 60 80 100 2.8 2.9 3.1 3.0 d v out (v) - 20 0 20 40 - 40 60 80 100 4.8 4.9 5.1 5.0 d v out (v) v in =2 v, i out =30 ma, sel=l, on/off=h ta ( c ) v in =3 v, i out =30 ma, sel2=on/off=h ta ( c ) 4.0 v out ( v ) 4.0 3.0 2.0 1.0 0 5 v in =0.9 v, l=100 m h (fl5h101k), di : d1ns4, ta=25 c 10 15 20 v out ( v ) 3.0 2.0 1.0 0 5 10 15 20 v in =0.9 v, l=100 m h (fl5h101k), di : d1ns4, ta=25 c 5.0 17.1 v out =3 v, sel=l, on/off=h 17.2 v out =5 v, sel2=on/off=h i out (ma) i out (ma) ( t y p. ) - 20 ta 0 20 40 - 40 60 80 100 0 20 40 60 80 100 t on ( ns ) ( t y p. ) - 20 ta ( c) 0 20 40 - 40 60 80 100 300 400 500 600 700 800 t off (ns) 18.1 risin g time ( t on ) - ambient temperature ( ta ) 18.2 falling time (t off ) - ambient temperature (ta)

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