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al3050 document number: d s38578 rev. 2 - 2 1 of 16 www.diodes.com july 2016 ? diodes incorporated al3050 small panel backlight led driver description the al3050 is a current mode boost - type led driver with programmable brightness dimming control for portable devices . with a 3 0 v rated integrated mosfet and power diode , the al3050 can support up to 8 leds in series. the small solution size, advanced dimming features and high efficiency are suitable for led backlight solutions for single cell li - ion based equipment. the boost converter runs at 750khz fixed switching frequency to reduce output ripp le, improve conversion efficiency, and allows for the use of small external components. the default led current is adjustable by an external resister at fb pin and the feedback voltage is regulated to 200mv typically. the al3050 provides pwm dimming mode and single wire digital dimming mode for accurate led current control from ctrl pin. in pwm dimming mode, the feedback reference voltage is changed with the pwm duty cycle proportionally and the available pwm frequency range is from 20 khz to 100 khz. in single wire digital dimming mode, it provides a programmable 32 - step brightness dimming function with the ctrl pin setting. the al3050 provides protection functions including under voltage lockout, over voltage protection, over current protectio n and over temperature protection to protect the circuit . the al3050 is available in u - dfn2020 - 6 (type s) packages. features ? 2.7v to 5.5v input voltage range ? 28v open led protection (up to 8 leds) ? integrated 0. 7 a / 30v internal mos fet and power diode ? 200mv reference w ith 3 % accuracy ? 750khz switching frequency ? flexible digital and pwm brightness control ? s ingle w ire control interface ? pwm dimming control interface ? up to 100:1 pwm dimming ratio ? integrated loop compensation ? built - in soft - start ? built - in o tp ? built - in ocp ? tiny package with u - dfn2020 - 6 (type s) package ? totally lead - free & fully r o hs compliant (notes 1 & 2) ? halogen and antimony free. green device (note 3 ) pin assignments ( top view ) u - dfn2020 - 6 (type s) applications ? feature phones ? smart phones ? portable media players ? ultra mobile devices ? gps receivers ? backlight for small and media form factor lcd display notes: 1. no purposely added lead. fully eu directive 2002/95/ec (r o hs) & 2011/65/eu (r o hs 2) compliant. 2. see http://www.diodes.com/quality/lead_free.html for more information about diodes incorporateds definitions of halogen - and antimony - free, "green" and lead - free. 3. halogen - and antimony - free "green products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total br + cl) and <1000ppm antimony compounds. 3 2 1 6 5 4 c t r l v i n v o u t f b g n d s w t h e r m a l p a d
al3050 document number: d s38578 rev. 2 - 2 2 of 16 www.diodes.com july 2016 ? diodes incorporated al3050 typical applications circuit pin description s pin number pin name function 1 ctrl control pin of the boost converter. it is a multi - functional pin which can be used for enable control, pwm and digital dimming. 2 v in supply input pin. a capacitor should be connected between the v in pin and gnd pin to keep the dc input voltage constant. 3 vout output of the boost converter . 4 fb feedback pin for current . connect a resistor between this pin and gnd to set the current. 5 gnd ground. 6 sw this is the switching node of the ic. connect the inductor between the vin and sw pin. - thermal pad the thermal pad should be soldered to the analog ground plane. if possible, use thermal via to connect to ground plane for ideal power dissipation. functional block diagram 2 . 7 v t o 5 . 5 v v b a t c i n 2 . 2 f l 2 2 h a l 3 0 5 0 v i n s w c t r l v o u t g n d f b p w m o r s i n g l e w i r e d i m m i n g c o n t r o l c o u t 1 f u p t o 8 l e d s r f b 1 0 w v i n s w c t r l v o u t f b u v l o s o f t s t a r t - u p o s c g a t e d r i v e r c o n t r o l r a m p g e n e r a t o r c o m p + - + + - c u r r e n t s e n s o r e r r o r a m p + - v r e f p w m & e a s y s c a l e r e f e r e n c e c o n t r o l o v p d e t e c t i o n g n d
al3050 document number: d s38578 rev. 2 - 2 3 of 16 www.diodes.com july 2016 ? diodes incorporated al3050 absolute maximum ratings (@ t a = +25 c, unles s otherwise specified.) ( note 4 ) symbol parameter rating unit v in input pin voltage - 0.3 to 6 v v vout , v sw vout and sw pin voltage - 0.3 to 3 2 v v fb , v ctrl fb and ctrl pin voltage - 0.3 to 6 v ja thermal resistance ( junction to a mbient ) u - dfn2020 - 6 (t ype s) 70.4 o c /w t j operating junction temperature + 150 o c t stg storage temperature - 65 to + 150 o c esd esd (human body model) 2000 v esd (machine model) 2 00 v note: 4 . stresses greater than those listed under absolute maximum ratings may cause per manent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating condi tions is not implied. exposure to absolute maximum ratings for extended periods may affect device reliability. recommended operating conditions (@ t a = +25c, unless otherwise specified.) symbol parameter min max unit v in input voltage 2.7 5.5 v v o output voltage v in 30 v i o output current - 40 ma f pwm pwm dimming frequency 20 100 khz t a operating ambient temperature - 40 + 85 oc t j operating junction temperature - 40 + 125 oc
al3050 document number: d s38578 rev. 2 - 2 4 of 16 www.diodes.com july 2016 ? diodes incorporated al3050 electrical characteristics (v in = 3.6 v, ctrl = high , t a = +25c , unless otherwise specified.) symbol parameter condition min typ max unit supply voltage (vin pin) v in input v oltage - 2.7 - 5.5 v i q quiescent current device enable, no switching and n o l oad ( v fb = 0.4v) - 0.3 0.5 ma device enable, sw itching 750khz and no load ( v fb = 0v) - 0.5 1.65 i shdn shutdown supply current crtl = gnd - 0.1 1 a under voltage lockout v uvlo input uvlo threshold v in ramp down - 2.2 2. 3 5 v v in ramp up - 2.5 2.65 v v hys input uvlo hysteresis - - 300 - mv enable control v ctrl - h ctrl logic high voltage - 1.2 - - v v ctrl - l ctrl logic low voltage - - - 0.4 v r ctrl ctrl pull down resistor - - 3 00 - k t off (note 5) ctrl pulse with to shutdown ctrl from high to low 3 .5 - - ms feedback and reference (fb pin) v ref feedback reference voltage duty = 100% 19 4 200 20 6 mv i fb feedback input bias current v fb = 200mv - - 2 a t ref (note 5) v ref filter time constant - - 230 - s high frequency oscillator f osc oscillator frequency - 600 750 900 khz d max (note 5) maximum duty cycle v fb = 0v, measured on the drive signal of the switch mosfet 88 9 4 - % power switch an d diode r ds(on) n - mosfet on - resistance v in = 3.6v - 0.56 1 v f power diode forward voltage i diode = 0.2a - 0.75 1 v i l eak _ sw sw p in leakage current v sw = 28 v - 0.1 2 a protection logic i lim n - mosfet current limit d = d max 0. 6 0. 7 0. 84 a i lim _ open led open current limit led open - 0.3 - a v ovp open led protection threshold measured on the vout pin 27 28.2 30 v t otsd (note 5) thermal shutdown threshold - - + 160 - oc t hys (note 5) thermal shutdown hysteresis - - + 20 - oc digital dimming timing ( note 5) t 1w _ det digital dimming detection time ctrl pin low 450 - - s t 1w _ delay digital dimming detection delay - 100 - - s t 1w _ win digital dimming detection window time measured from ctrl high 3.5 - - ms t start start time of program stream - 3.5 - - s t eos end time of program stream 3.5 - 600 s t h _ lb high time l ow bit logic 0 3.5 - 300 s t l _ lb low time low bit logic 0 2t h _ lb - 600 s t h _ hb high time high bit logic 1 2t l _ hb - 600 s t l _ hb low time high bit logic 1 3.5 - 300 s v ackn acknowledge output voltage low open drain, r pull - up =15k to vin - - 0.4 v t val _ ackn acknowledge valid time - - - 3.5 s t ackn duration of acknowledge condition - - - 900 s note : 5 . guaranteed by design .
al3050 document number: d s38578 rev. 2 - 2 5 of 16 www.diodes.com july 2016 ? diodes incorporated al3050 performance characteristics (v in = 3.6 v, l = 22 h, r fb = 10 , 8 leds in series, t a = + 25c , unless otherwise specified . ) fb vs. vin p in voltage fb vs. temperature c urrent l imit vs. vin p in v oltage current limit vs. t emperature current limit @led o pen vs. vin p in v oltage current limit @led o pen vs. temp erature 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 170 175 180 185 190 195 200 205 210 215 220 fb voltage (mv) vin pin voltage (v) t a =25 o c -50 -25 0 25 50 75 100 125 170 175 180 185 190 195 200 205 210 215 220 v in =3.6v fb voltage (mv) temperature ( o c) 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 i lim - current limit (a) vin pin voltage (v) t a =25 o c -50 -25 0 25 50 75 100 125 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 i lim - current limit (a) temperature ( o c) v in =3.6v 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 0.0 0.1 0.2 0.3 0.4 0.5 0.6 i lim_open - current limit @ led open (a) vin pin voltage (v) t a =25 o c -50 -25 0 25 50 75 100 125 0.0 0.1 0.2 0.3 0.4 0.5 0.6 i lim_open - current limit @ led open (a) temperature ( o c) v in =3.6v
al3050 document number: d s38578 rev. 2 - 2 6 of 16 www.diodes.com july 2016 ? diodes incorporated al3050 performance characteristics (v in = 3.6 v, l = 22 h, r fb = 10 , 8 leds in series, t a = + 25c , unless otherwise specif ied. ) fb vs. pwm duty cycle fb vs. easy scale step efficiency vs. pwm duty cycle efficiency vs. pwm duty cy cle efficiency vs. pwm duty cycle 0 10 20 30 40 50 60 70 80 90 100 0 20 40 60 80 100 120 140 160 180 200 220 pwm duty cycle (%) fb voltage (mv) f pwm =20khz f pwm =40khz 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 0 20 40 60 80 100 120 140 160 180 200 v in =3.6v fb voltage (mv) easy scale step 0 10 20 30 40 50 60 70 80 90 100 50 55 60 65 70 75 80 85 90 95 100 efficiency (%) duty cycle (%) v in =3.6v, l=22 ? h r fb =10 w 6leds (v out =19.8v) 8leds (v out =26.3v) 0 10 20 30 40 50 60 70 80 90 100 50 55 60 65 70 75 80 85 90 95 100 v in =3v v in =3.6v v in =4.2v v in =5v efficiency(%) duty cycle (%) l=22 ? h 6leds(v out =19.8v) r fb =10 w 0 10 20 30 40 50 60 70 80 90 100 50 55 60 65 70 75 80 85 90 95 100 v in =3v v in =3.6v v in =4.2v v in =5v efficiency(%) duty cycle (%) l=22 ? h 8leds(v out =26.3v) r fb =10 w
al3050 document number: d s38578 rev. 2 - 2 7 of 16 www.diodes.com july 2016 ? diodes incorporated al3050 performance characteristics (v in = 3.6 v, l = 22 h, r fb = 10 , 8 leds in series, t a = + 25c , unless otherwise specified. ) steady state steady state pwm dimming duty=100% pwm dimming duty=25% start up start up pwm dimming duty=100% pwm dimming duty=25% shutdown shutdown pwm dimming duty=100% pwm dimming duty=25% v sw 2 0v/div v out_a c 2 00mv/div i l 10 0ma/div time 1 ? s/div time 1 ? s/div time 1m s/div time 1m s/div v sw 2 0v/div v out_ac 5 0mv/div i l 10 0ma/div v sw 2 0v/div v ctrl 2 v/div i l 2 00ma/div v fb 200m v/div v sw 2 0v/div v ctrl 2 v/div i l 1 00ma/div v fb 50m v/div time 1m s/div time 1m s/div v sw 2 0v/div v ctrl 2 v/div i l 2 00ma/div v fb 200m v/div v sw 2 0v/div v ctrl 2 v/div i l 1 00ma/div v fb 50m v/div
al3050 document number: d s38578 rev. 2 - 2 8 of 16 www.diodes.com july 2016 ? diodes incorporated al3050 performance characteristics (v in = 3.6 v, l = 22 h, r fb = 10 , 8 leds in series, t a = + 2 5c , unless otherwise specified. ) open led protection application information 1. general operation the al3050 is a high efficiency boost converter with integrated power diode in a small package size. the device is ideal for driving white led in series. the serial led connection provides even illumination by sourcing the same output current through all leds, eliminating the need for expensive factory calibration. the device integrates a 3 0v/0.7a low side switch mosfet and a 30v power diode, and operates in pulse width modulation (pwm) with 750 khz fixed switching frequency. for operation see the block diagram. the duty cycle of the converter is set by the error amplifier output and the cur rent signal applied to the pwm control comparator. the control architecture is based on traditional current - mode control; therefore, slope compensation is added to the current signal to allow stable operation for duty cycles larger than 50%. the feedback l oop regulates the fb pin to a low reference voltage (200mv typical), reducing the power dissipation in the current sense resistor. 2. soft start - up soft - start circuitry is integrated into the ic to avoid a high inrush current during start - up. after the de vice is enabled, the voltage at fb pin ramps up slowly to the reference voltage in 32 steps with each step taking 341 s . this ensures that the output voltage rises slowly to reduce the input current. additionally, during the start up process, the current limit of the switch is set to half of the normal current limit spec. during this period, the input current is kept bel ow 360ma (typical). 3. open led protection open led protection circuitry prevents ic damage as the result of white led disconnection. the al3050 monitors the voltages at the vout pin and fb pin. the circuitry turns off the switch mos fet and shuts down the ic completely if both of the following two conditions are met: 1) the vout voltage reaches ovp threshold (28.2v typical), 2) fb voltage is lower than half of its regulation voltage. this means the led string is open or the fb pin is short to ground. durin g open led condition, the cycle by cycle switch current limit is set to be 0.3a typically to protect external devices. as a result, the output voltage falls to the level of the input supply. the device remains in shutdown mode until it is enabled by pullin g down the ctrl pin logic low for at least 3.5ms and then pulling it high. 4 . shutdown the al3050 enters shutdown mode when the ctrl voltage is logic low for more than 3.5ms. during shutdown, the input supply current for the device is less than 1a (max). although the internal mos fet does not switch in shutdown mode, there is still a dc current path between the input and the leds through the inductor and the power diode. the minimum f orward voltage of the led array must exceed the maximum input voltage to ensure that the leds remain off in shutdown. in the typical application with two or more leds, the forward voltage is large enough to reverse bias the diode and keep leakage current l ow. 5. current setting the fb voltage is regulated by a low 0.2v reference voltage. the led current is programmed externally using a current - sense resistor in series with the led string. the led current can be calculated by equation 1 : (1) time 10 ? s /div v fb 200m v/div v out 10 v/div i l 2 00ma/div v sw 2 0v/div set fb led r v i ?
al3050 document number: d s38578 rev. 2 - 2 9 of 16 www.diodes.com july 2016 ? diodes incorporated al3050 application information (cont.) w here = full - scale output current of leds = 200mv ( regulated voltage of fb ) = current sense resistor at fb pin the output current tolerance depends on the fb accuracy and the current sensor resistor accuracy. 6. led bright ness dimming mode selection the ctrl pin is used for the control input for both dimming modes, pwm dimming and single wire dimming. the dimming mode for the al3050 is selected each time the device is enabled. the default dimming mode is pwm dimming. to enter the single wire mode, the following digital pattern on the ctrl pin must be recognized by the ic every time the ic starts from the shutdown mode. 1. pull ctrl pin high to enable the al3050, and to start the single wire dimming detecti on window; 2. a fter the single wire dimming detection delay (t 1 w_delay , 100 s ) expires, drive the ctrl pin low for more than single wire detection time (t 1w_ det , 450 s ); 3. the ctrl pin has to be low for more than t 1w_ det before the sing le wire dimming detection window (t 1w_win , 3.5ms) expires. s ingle wire detection window starts from the first ctrl pin low to high transition. if all above three conditions are fulfilled , the ic enters single wire dimming mode, otherwise enters pwm dimming mode. once the dimming mode is programmed, it can not be changed without another start up. this means the ic needs to be shut down by pulling the ctrl low for 3.5 ms and restarts. see the dimming mode detection and soft start (figure 1 ) for a graphical explanation. figure 1 . dimming mode detection and soft start 7. pwm dimming mode when the ctrl pin is constantly high, the fb voltage is regulat ed to 200mv typically. however, the ctrl pin allows a pwm signal to reduce this regulation voltage; therefore, it achieves led brightness dimming. the relationship between the duty cycle and fb voltage is given by equation 2. (2) where duty = duty cycle of the pwm signal 200mv = internal reference voltage led i fb v set r c t r l f b d u t y * 2 0 0 m v t o f f > 3 . 5 m s 0 m v ( f p w m > 2 0 k h z ) t 1 w _ w i n > 3 . 5 m s s t a r t u p d e l a y s h u t d o w n c t r l p r o g r a m c o d e t 1 w _ w i n > 3 . 5 m s t 1 w _ d e t > 4 5 0 s t 1 w _ d e l a y > 1 0 0 s 2 0 0 m v 1 0 0 m v 0 m v f b t o f f > 3 . 5 m s p r o g r a m c o d e s h u t d o w n mv duty v fb 200 ? ?
al3050 document number: d s38578 rev. 2 - 2 10 of 16 www.diodes.com july 2016 ? diodes incorporated al3050 application informatio n (cont.) figure 2 . block diagram of programmable fb voltage i n pwm dimming mode as shown in figure 2, t he al3050 chops up the internal 200mv reference voltage at the duty cycle of the pwm signal. the pulse signal is then filtered by an internal low pass filter. the output of the filter is connected to the error amplifier as the reference voltage for the fb pin regulation. therefore, although a pwm signal is used for brightness dimming, only the led dc current is modulated , which is often referred as analog dimming. this eliminates the audible noise which often occurs when the led current is pulsed in replica of the frequency and duty cycle of pwm control. for optimum performance, use the p wm dimming frequency in the range of 20 khz to 100khz. since the ctrl pin is logic only pin, adding an external rc filter applied to the pin does not work. the minimum dimming duty cycle the ic can support is 1% within the pwm dimming frequency range 20khz to 100khz. 8. s ingle w ire digital dimming mode the ctrl pin features a simple digital interface to allow digital brightness control. the digital dimming can save the processor power and battery life as it does not require a pwm signal all the time, and the processor can enter idle mode if available. the al3050 adopts a single wire digital protocol for the digital dimming mode control , which can program the fb voltage to any of the 32 steps with single command. the step increment increases wit h the voltage to produce pseudo logarithmic curve for the brightness step. see the table 1 for the fb pin voltage steps. the default step is full scale when the device is first enabled (v fb = 200 mv). the programmed reference voltage is stored in an interna l register. a power reset clears the register value and reset it to default. c t r l v b g 2 0 0 m v e r r o r a m p l i f i e r e a o u t p u t f b
al3050 document number: d s38578 rev. 2 - 2 11 of 16 www.diodes.com july 2016 ? diodes incorporated al3050 application information (cont.) - fb voltage (mv) d4 d3 d2 d1 d0 0 0 0 0 0 0 0 1 5 0 0 0 0 1 2 8 0 0 0 1 0 3 11 0 0 0 1 1 4 14 0 0 1 0 0 5 17 0 0 1 0 1 6 20 0 0 1 1 0 7 23 0 0 1 1 1 8 26 0 1 0 0 0 9 29 0 1 0 0 1 10 32 0 1 0 1 0 11 35 0 1 0 1 1 12 38 0 1 1 0 0 13 44 0 1 1 0 1 14 50 0 1 1 1 0 15 56 0 1 1 1 1 16 62 1 0 0 0 0 17 68 1 0 0 0 1 18 74 1 0 0 1 0 19 80 1 0 0 1 1 20 86 1 0 1 0 0 21 92 1 0 1 0 1 22 98 1 0 1 1 0 23 104 1 0 1 1 1 24 116 1 1 0 0 0 25 128 1 1 0 0 1 26 140 1 1 0 1 0 27 152 1 1 0 1 1 28 164 1 1 1 0 0 29 176 1 1 1 0 1 30 188 1 1 1 1 0 31 200 1 1 1 1 1 table 1. 32 - step digital dimming setting the digital dimming interface is based on a master - slave structure, where the master is typically a microcontroller or application processor. figure 3 and table 2 give an overview of the protocol. the protocol consists of a device specific ad dress byte and a data byte. the device specific address byte is fixed to 58 hex. the data byte consists of five bits for information, two address bits ("00"), and the rfa bit. the rfa bit set to high indicates the request for acknowledge condition. the ack nowledge condition is only applied if the protocol was received correctly. the advantage of single wire digital dimming compared with other on pin interfaces is that its bit detection is in a large extent independent from the bit transmission rate. i t can automatically detect bit rates between 1. 1 kbit/sec and up to 1 0 0kbit/sec. figure 3 . s ingle w ire digital protocol overview d a 6 1 d a 7 0 d a 5 1 d a 4 1 d a 3 0 s t a r t 0 1 d a 2 d a 1 0 d a 0 e o s a 1 r f a a 0 d 4 d 3 s t a r t d 2 d 1 d 0 e o s d a t a i n d a t a o u t a c k d a t a b y t e d e v i c e a d d r e s s
al3050 document number: d s38578 rev. 2 - 2 12 of 16 www.diodes.com july 2016 ? diodes incorporated al3050 application information (cont.) b yte b it n umber n ame t ransmission d irection d escription device address byte 72 h ex 7 da7 in 0 (msb device address) 6 da6 1 5 da5 0 4 da4 1 3 da3 1 2 da2 0 1 da1 0 0 da0 0 (lsb device address) data byte 7 (msb) rfa in request for acknowledge. if high, acknowledge is applied by device. 6 a1 0 (address bit a1) 5 a0 0 (address bit a0) 4 d4 data bit d4 3 d3 data bit d3 2 d2 data bit d2 1 d1 data bit d1 0 (lsb) d0 data bit d0 - - ack out acknowledge condition active 0, this condition will only be applied to case rfa bit is set. open drain output, line needs to be pulled high by the host with a pullup resistor. this feature can only be used if the master has an open drain output stage. in case of a push pull output stage , a cknowledge condition may not be requested! table 2 . s ingle w ire dimming bit description all bits are transmitted msb first and lsb last. figure 4 shows the protocol without acknowledge request (bit rfa = 0), figure 5 with acknowledge (bit rfa = 1) request. prior to both bytes, device address byte a nd data byte, a start condition must be applied. for this, the ctrl pin must be pulled high for at least t start ( 3.5 s) before the bit transmission starts with the falling edge. if the ctrl pin is already at high level, no start condition is needed prior to the device address byte. the transmission of each byte is closed with an end of stream condition for at least t eos ( 3.5 s). the bit detection is based on a logic detection scheme, where the criterion is the relation between t low and t high (refer to figure 6 ). it can be simplified to: high bit: t high > t low , but with t high at least 2x t low . low bit: t high < t low , but with t low at least 2x t high . the bit detection starts with a falling edge on the ctrl pin and ends with the next falling edge. depending on the relation between t high and t low , the logic 0 or 1 is detected. the acknowled ge condition is only applied if: ? acknowledge is requested by setting rfa bit to 1. ? the transmitted device address matches with the device address of the device. ? device address byte and data byte are received correctly.
al3050 document number: d s38578 rev. 2 - 2 13 of 16 www.diodes.com july 2016 ? diodes incorporated al3050 application information (co nt.) if above conditions are met, after t val _ ack n (3.5s) delay from the moment when the last falling edge of the protocol is detected, an internal ackn - mosfet is turned on to pull the ctrl pin low for the time t ackn (900s maximum), then the acknowledge condition is valid. during the t val _ ack n delay, the master controller keeps the line low; after the delay, it should release the line by outputting high impedance and then detect the acknowledge condition. if it reads back a logic 0, it means the ic has received the command correctly. the ctrl pin can be used again by the master when the acknowledge condition ends after t ackn time. note that the acknowledge condition may only be requested in case the master device has an open drain output. for a pus h - pull output stage, the use a series resistor in the crtl line to limit the current to 500a is recommended to for such cases as: ? an accidentally requested acknowledge, or ? to protect the internal ackn - mosfet. figure 4 . s ingle w ire digital dimming timing, without a cknowledge rfa=0 figure 5 . s ingle w ire digital dimming timing, with a cknowledge rfa=1 / / / / t s t a r t s t a t i c h i g h d a 7 0 a d d r e s s b y t e d a 0 0 t e o s t s t a r t r f a 0 d a t a b y t e d o 1 t e o s s t a t i c h i g h d a t a i n / / / / t s t a r t s t a t i c h i g h d a 7 0 a d d r e s s b y t e d a 0 0 t e o s t s t a r t r f a 1 d a t a b y t e d o 1 t v a l a c k n d a t a i n d a t a o u t a c k n t a c k n s t a t i c h i g h a c k n o w l e d g e t r u e , d a t a l i n e p u l l e d d o w n b y d e v i c e c o n t r o l l e r n e e d s t o p u l l u p d a t a l i n e v i a a r e s i s t o r t o d e t e c t a c k n a c k n o w l e d g e f a l s e , n o p u l l d o w n
al3050 document number: d s38578 rev. 2 - 2 14 of 16 www.diodes.com july 2016 ? diodes incorporated al3050 application information (cont.) fi gure 6. s ingle w ire digital dimming - bit coding 9. under voltage lockout an under voltage lockout prevents operation of the device at input voltages below typical 2.2v. when the input voltage is below the under voltage threshold, the device is shut down and the internal switch is turned off. if the input voltage rises by under voltage lockout hysteresis, the ic restarts. 10. thermal shutdown an internal thermal shutdown turns off the device when the typical junction temperature of + 160c is exceeded . the device is released from shutdown automatically when the junction temperature decreases by + 20 c. ordering information part number package c ode package 7 tape and reel quantity part number suffix a l3050 fdc - 7 fd c u - dfn2020 - 6 (type s) 30 00/tape & reel - 7 marking information u - dfn2020 - 6 (type s) part number package identification code a l3050 fdc - 7 u - dfn2020 - 6 (type s) z9 / / / / l o w b i t h i g h b i t a l 3 0 5 0 x - x p a c k i n g p a c k a g e 7 : 7 " t a p e & r e e l p r o d u c t n a m e f d c : u - d f n 2 0 2 0 - 6 ( t y p e s ) ( t o p v i e w ) x x y : y e a r : 0 ~ 9 x : i n t e r n a l c o d e x x : i d e n t i f i c a t i o n c o d e w : w e e k : a ~ z : 1 ~ 2 6 w e e k ; a ~ z : 2 7 ~ 5 2 w e e k ; z r e p r e s e n t s 5 2 a n d 5 3 w e e k y w x
al3050 document number: d s38578 rev. 2 - 2 15 of 16 www.diodes.com july 2016 ? diodes incorporated al3050 package outline dimensions please see http://www.diodes.co m/package - outlines.html for the latest version. u - dfn2020 - 6 (type s) u - dfn2020 - 6 (type s) dim min max typ a 0.51 0.61 0.56 a1 0.00 0.05 0.02 a3 -- -- 0.203 b 0.25 0.35 0.30 d 1.95 2.05 2.00 d2 1.55 1.75 1.65 e 1.95 2.05 2.00 e2 0.86 1.06 0.96 e 0.650 bsc k -- -- 0.22 l 0.25 0.35 0.30 z -- -- 0.20 z1 -- -- 0.175 all dimensions in mm suggested pad layout please see http://www .diodes.com/package - outlines.html for the latest version. u - dfn2020 - 6 (type s) dimensions value (in mm) c 0.650 g 0.150 x 0.400 x1 1.690 x2 1.700 y 0.500 y1 1.000 y2 2.300 d d2 e b e2 a a3 seating plane pin #1 id a1 e l z k z1 y g x2 y2 y1 x1 c x
al3050 document number: d s38578 rev. 2 - 2 16 of 16 www.diodes.com july 2016 ? diodes incorporated al3050 important notice diodes incorporated makes no warranty of any kind, express or implied, with regards to this document, including, but not lim ited to, the implied warranties of merchantability and fitness for a particular purpose (and their equivalents under the laws of any jurisdiction). diodes incorporated and its subsidiaries reserve the right to make modifications, enhancements, improveme nts, corrections or other changes without further notice to this document and any product described herein. diodes incorporated does not assume any liability a rising out of the application or use of this document or any product described herein; neither do es diodes incorporated convey any license under its patent or trademark rights, nor the rights of others. any customer or user of this document or products described herein in such appli cations shall assume all risks of such use and will agree to hold dio des incorporated and all the companies whose products are represented on diodes incorporated website, harmless against all damages. diodes incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unau thorized sales channel. should customers purchase or use diodes incorporated products for any unintended or unauthorized application, customers shall indemnify and hold diodes incorporated and its representatives harmless against all claims, damages, expen ses, and attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application. products described herein may be covered by one or more united states, international or forei gn patents pending. product names and markings noted herein may also be covered by one or more united states, international or foreign trademarks. this document is written in english but may be translated into multiple languages for reference. only the english version of this document is the final and determinative format released by diodes incorporated. life support diodes incorporated products are specifically not authorized for use as critical components in life support devices or system s without th e express written approval of the chief executive officer of diodes incorporated. as used herein: a. life support devices or systems are devices or systems which: 1. are intended to implant into the body, or 2. support or sustain life and whose failu re to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in significant injury to the user. b. a critical component is any component in a life support device or system w hose failure to perform can be reasonably expected to cause the failure of the life support device or to affect its safety or effectiveness. customers represent that they have all necessary expertise in the safety and regulatory ramifications of t heir life support devices or systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety - related requirements concerning their products and any use of diodes incorporated products in such safety - critical, life s upport devices or systems, notwithstanding any devices - or systems - related information or support that may be provided by diodes incorporated. further, customers must fully indemnify diodes incorpora ted and its representatives against any damages arising out of the use of diodes incorporated products in such safety - critical, life support devices or systems. copyright ? 201 6 , diodes incorporated www.diodes.com

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