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innovative power tm - 1 - www.active - semi.com copyright ? 2015 active - semi, inc. ACT4525 40v/3.5a cv/cc buck converter with usb auto C detect rev 1.1, december 17 th , 2015 features ? pass apple mfi test ? 40v input voltage surge ? 4.5v - 36v operational input voltage ? dual 5.1v outputs with 1% accuracy ? up to 3.5a output current ? 2.65a constant current regulation for vout1 ? 1.2a constant current regulation for vout2 ? usb auto - detect support apple 2.4a, samsung and bc1.2 devices ? hiccup mode protection at output short ? 90% efficiency at full load ? 0.5ma low standby input current ? 5.7v output over voltage protection ? cord voltage drop compensation ? meet en55022 class b radiated emi standard ? 8kv esd hbm protection on dp and dm ? sop - 8ep package applications ? car charger ? cigarette lighter adaptor (cla) ? rechargeable portable device ? cv/cc regulation dc/dc converter general description ACT4525 is a wide input voltage, high efficiency step - down dc/dc converter that operates in either cv (constant output voltage) mode or cc (constant output current) mode. ACT4525 has separated output current limits for dual port cla applications. with the separated current limits, the cla can meet apple s mfi standard. ACT4525 provides up to 3.5a output current at 125khz switching frequency. ACT4525 builds in usb auto - detect algorithms to recognize apple, samsung, and bc1.2 devices to ensure maximum charge current to attached devices. ACT4525 utilize adaptive drive technique to achieve good emi performance while main 90% efficiency at full load for mini size cla designs. ACT4525 also built in output short circuit protection with hiccup mode. the average output current is reduced to below 6ma when output is shorted to ground. other features include output over voltage protection and thermal shutdown. the devices are available in a sop - 8ep package and require very few external devices for operation. typical application circuit * patent pending v/i profile 2 . 4 a 2 . 9 a 5 . 25 v 4 . 95 v 5 . 10 v vout 1 iout 1 3 . 2 0 v act 4525 hsb in sw 4 . 5 v to 40 v dm r cs 1 25 m csp dp v out gnd d - d + gnd csn 1 5 . 1 v / 2 . 4 a c 2 10 f c 3 22 nf c 5 470 f c 1 47 f c 4 10 f c 6 2 . 2 f d 1 s k 54 l l 1 33 h v out gnd d - d + 5 . 1 v / 1 a csn 2 r cs 2 50 m c 7 2 . 2 f 1 . 1 a 1 . 3 a 5 . 25 v 4 . 95 v 5 . 10 v vout 2 iout 2 3 . 2 0 v
ACT4525 rev1.1, december 17 th , 2015 innovative power tm - 2 - www.active - semi.com copyright ? 2015 active - semi, inc. ordering information pin configuration top view part number operation temper a- ture range package frequency packing ACT4525yh - t - 40c to 85c sop - 8ep 125khz tape & reel 8 7 6 5 1 2 3 4 c s p c s n 1 g n d d p i n d m s w h s b e p a c t 4 5 2 5 s o p - 8 e p c s n 2
ACT4525 rev1.1, december 17 th , 2015 innovative power tm - 3 - www.active - semi.com copyright ? 2015 active - semi, inc. absolute maximum rat ings ? ? : do not exceed these limits to prevent damage to the device. exposure to absolute maximum rating conditions for long periods ma y affect device reliability. pin descriptions pin name description 1 csp voltage feedback input. connect to node of the inductor and output capacitor. csp, csn1 and csn2 kevin sensing is recommended. 2 csn1 output current sense negative input. connect to the negative terminal of current sense resistor for vout1. 3 csn2 output current sense negative input. connect to the negative terminal of current sense resistor for vout2. 4 dp data line positive input. connected to d+ of attached portable device data line. this pin passes 8kv hbm esd. 5 dm data line negative input. connected to d - of attached portable device data line. this pin passes 8kv hbm esd. 6 in power supply input. bypass this pin with a 10 f ceramic capacitor to gnd, placed as close to the ic as possible. 7 sw power switching output to external inductor. 8 hsb high side bias pin. this provides power to the internal high - side mosfet gate driver. connect a 22nf capacitor from hsb pin to sw pin. 9 gnd ground and heat dissipation pad. connect this exposed pad to large ground copper area with copper and vias. parameter value unit in to gnd - 0.3 to 40 v sw to gnd - 1 to v in +1 v hsb to gnd v sw - 0.3 to v sw + 7 v csp, csn1, csn2, dp , dm to gnd - 0.3 to +6 v junction to ambient thermal resistance 46 c /w operating junction temperature - 40 to 150 c storage junction temperature - 55 to 150 c lead temperature (soldering 10 sec.) 300 c
ACT4525 rev1.1, december 17 th , 2015 innovative power tm - 4 - www.active - semi.com copyright ? 2015 active - semi, inc. parameter symbol condition min typ max units input over voltage protection vin_ovp rising 40 42 44 v input over voltage hysteresis 4 v input over voltage response time t_vin_ovp vin step from 30v to 45v 250 ns input under voltage lockout (uvlo) vin rising 4.5 v input uvlo hysteresis 200 mv input voltage power good deglitch time no ovp 40 ms input voltage power good deglitch time no uvp 10 us input standby current vin=12v, vout=5.1v, iload=0 500 ua output voltage regulation csp 5.05 5.1 5.15 v output over voltage protection (ovp) output rising 5.7 v output over voltage deglitch time 1.0 us output voltage cord compensation output current 2.4a - 15% 100 +15% mv output under voltage protection (uvp) vout vout falling - 10% 3.2 10% v uvp hysteresis vout vout rising 0.2 v uvp deglitch time vout 10 us uvp blanking time at startup 3.5 ms cc1 rcs=25m 2.50 2.65 2.80 a output constant current limit cc2 rcs=50m 1.1 1.2 1.3 a hiccup waiting time 4.13 s top fet cycle by cycle current limit 4.5 5.8 a top fet rdson 70 m ? bottom fet rdson 4.7 ? maximum duty cycle 99 % switching frequency - 10% 125 +10% khz soft - start time 2.0 ms electrical character istics (v in = 12v, t a = 25c, unless otherwise specified.)
ACT4525 rev1.1, december 17 th , 2015 innovative power tm - 5 - www.active - semi.com copyright ? 2015 active - semi, inc. parameter symbol condition min typ max units out voltage ripples cout=470uf/22uf ceramic 80 mv line transient response input 12v - 40v - 12v with 1v/us slew rate, vout=5v, iload=0a and 2.4a 4.75 5.25 v load transient response vout=5v 80ma - 1.0a - 80ma load with 0.1a/us slew rate 4.9 5.15 5.4 v thermal shut down 160 c thermal shut down hysteresis 30 c esd of dp, dm hbm 8 kv electrical character istics (v in = 12v, t a = 25c, unless otherwise specified.)
ACT4525 rev1.1, december 17 th , 2015 innovative power tm - 6 - www.active - semi.com copyright ? 2015 active - semi, inc. functional block dia gram functional description output current sensing and regulation sense resistor is connected to csp and csn1, csn2 respectively. the sensed differential voltages are compared with interval references to regulate currents. cc loop and cv loop are in parallel. the current loop response is allowed to have slower response compared to voltage loop. however, during current transient response, the inductor current overshoot/undershoot should be controlled within +/ - 25% to avoid inductor saturation. cycle - by - cycle current control the conventional cycle - by - cycle peak current mode is implemented with high - side fet current sense. input over voltage protection the converter is disabled if the input voltage is above 42v (+/ - 2v). device resumes operation automatically 40ms after ovp is cleared. output over voltage protection device stops switching when output over - voltage is sensed, and resumes operation automatically when output voltage drops to ovp - hysteresis. output under - voltage protection / hiccup mode there is a under voltage protection (uvp) threshold. if the uvp threshold is hit for 10us, an over current or short circuit is assumed, and the converter goes into hiccup mode by disabling the converter and restarts after hiccup waiting period. cord compensation in some applications, the output voltage is increased with output current to compensate the potential voltage drop across output cable. the compensation is based on the high side feedback resistance. the compensation voltage is derived as: vout = (v csp - v csn )*k this voltage difference could be added on the reference or turning the (v csp - v csn ) voltage into a sink current at fb pin to pull vout higher than programmed voltage. the cord compensation loop should be very slow to avoid potential disturbance to the voltage loop. the voltage loop should be sufficiently stable on various cord compensation setting. thermal shutdown if the t j increases beyond 160c, ACT4525 goes into hz mode and the timer is preserved until t j drops by 30c. p w m c o n t r o l l e r d r i v e r c u r r e n t s e n s e a n d c o n t r o l 7 0 m ? 4 . 7 ? o v p c s p c s n 1 c s n 2 g n d s w h s b u v l o v i n d p d m u s b a u t o d e t e c t
ACT4525 rev1.1, december 17 th , 2015 innovative power tm - 7 - www.active - semi.com copyright ? 2015 active - semi, inc. applications informa tion inductor selection the inductor maintains a continuous current to the output load. this inductor current has a ripple that is dependent on the inductance value. higher inductance reduces the peak - to - peak ripple current. the trade off for high inductance value is the increase in inductor core size and series resistance, and the reduction in current handling capability. in general, select an inductance value l based on ripple current requirement: where v in is the input voltage, v out is the output voltage, f sw is the switching frequency, i loadmax is the maximum load current, and k ripple is the ripple factor. typically, choose k ripple = 30% to correspond to the peak - to - peak ripple current being 30% of the maximum load current. with a selected inductor value the peak - to - peak inductor current is estimated as: the peak inductor current is estimated as: the selected inductor should not saturate at i lpk. the maximum output current is calculated as: l lim is the internal current limit. input capacitor the input capacitor needs to be carefully selected to maintain sufficiently low ripple at the supply input of the converter. a low esr capacitor is highly recommended. since large current flows in and out of this capacitor during switching, its esr also affects efficiency. the input capacitance needs to be higher than 10f. the best choice is the ceramic type. however, low esr tantalum or electrolytic types may also be used provided that the rms ripple current rating is higher than 50% of the output current. the input capacitor should be placed close to the in and gnd pins of the ic, with the shortest traces possible. in the case of tantalum or electrolytic types, a ceramic capacitor is recommended to parallel with tantalum or electrolytic capacitor, which should be placed right next to the ic. output capacitor the output capacitor also needs to have low esr to keep low output voltage ripple. the output ripple voltage is: where i outmax is the maximum output current, k ripple is the ripple factor, r esr is the esr of the output capacitor, f sw is the switching frequency, l is the inductor value, and c out is the output capacitance. in the case of ceramic output capacitors, r esr is very small and does not contribute to the ripple. therefore, a lower capacitance value can be used for ceramic type. in the case of tantalum or electrolytic capacitors, the ripple is dominated by r esr multiplied by the ripple current. in that case, the output capacitor is chosen to have sufficiently low esr. for ceramic output capacitor, typically choose a capacitance of about 22f. for tantalum or electrolytic capacitors, choose a capacitor with less than 50m esr. an 330f or 470f electrolytic capacitor is recommended. rectifier schottky diode use a schottky diode as the rectifier to conduct current when the high - side power switch is off. the schottky diode must have current rating higher than the maximum output current and a reverse voltage rating higher than the maximum input voltage. further more, the low forward voltage schottky is preferable for high efficiency and smoothly operation. current sense resistor the traces leading to and from the sense resistor can be significant error sources. with small value sense resistors, trace resistance shared with the load can cause significant errors. it is recommended to connect the sense resistor pads directly to the csp and csn pins using kelvin or 4 - wire connection techniques as shown below. (1) (2) (3) (4) (5) ( ) ripple loadmax sw in out in out k i f v v v v l _ = ( ) sw in out in out pk lpk f v l v v v i = _ _ pk lpk loadmax lpk _ i 2 1 i i + = pk lpk lim outmax i 2 1 i i _ _ = out sw in esr ripple outmax ripple lc f v r k i v 2 28 ? ? ? pcb load trace kevin sense traces sense resistor
ACT4525 rev1.1, december 17 th , 2015 innovative power tm - 8 - www.active - semi.com copyright ? 2015 active - semi, inc. applications informa tion pc board layout guidance when laying out the printed circuit board, the following checklist should be used to ensure proper operation of the ic. 1) arrange the power components to reduce the ac loop size consisting of c in , v in pin, sw pin and the schottky diode. 2) place input decoupling ceramic capacitor c in as close to vin pin as possible. c in is connected power gnd with vias or short and wide path. 3) use kelvin or 4 - wire connection techniques from the sense resistor pads directly to the csp and csn1, csn2 pins. 4) use copper plane and thermal vias for gnd for best heat dissipation and noise immunity. 5) use short trace connecting hsb - c hsb - sw loop. 6) sw pad is noise node switching from v in to gnd. it should be isolated away from the rest of circuit for good emi and low noise operation.
ACT4525 rev1.1, december 17 th , 2015 innovative power tm - 9 - www.active - semi.com copyright ? 2015 active - semi, inc. typical application circuit for 5v/3.4a car charger bom list for 5v/3.4a car charger item reference description manufacturer qty 1 u1 ic, ACT4525, sop - 8ep active - semi 1 2 c1 capacitor, electrolytic, 47f/35v murata, tdk 1 3 c2 capacitor, ceramic, 10f/25v, 1206, smd murata, tdk 1 4 c3 capacitor, ceramic, 22nf/25v, 0603, smd murata, tdk 1 5 c4 capacitor, ceramic, 10 f/10v, 1206, smd murata, tdk 1 6 c5 capacitor, electrolytic, 470f/10v murata, tdk 1 7 c6,c7 capacitor, ceramic, 2.2 f/10v, 0805, smd murata, tdk 2 8 l1 inductor, 33h, 4.5a, 20%, 1 9 d1 diode, schottky, 40v/5a, sk54l panjit 1 10 rcs1 chip resistor, 25m ?, 1206, 1/2w, 1% sart 1 11 rcs2 chip resistor, 50m ?, 1206, 1/2w, 1% sart 1 u 1 act 4525 hsb in sw 4 . 5 v to 40 v dm r cs 1 25 m csp dp v out gnd d - d + gnd csn 1 5 . 1 v / 2 . 4 a c 2 10 f c 3 22 nf c 5 470 f c 1 47 f c 4 10 f c 6 2 . 2 f d 1 sk 54 l l 1 33 h v out gnd d - d + 5 . 1 v / 1 a csn 2 r cs 2 50 m c 7 2 . 2 f
ACT4525 rev1.1, december 17 th , 2015 innovative power tm - 10 - www.active - semi.com copyright ? 2015 active - semi, inc. typical performance characteristics (schematic as show in typical application circuit, ta = 25c, unless otherwise specified) output1 cc/cv curve output voltage (v) 6.0 5.0 4.0 3.0 2.0 1.0 0 output current (ma) 0 500 1000 1500 2000 2500 3000 v in =24v v in =12v ACT4525 - 002 load transient (80ma - 1a - 80ma) vin=12v, vout=5v ACT4525 - 005 ch1: v out , 100mv/div ch2: i out , 1a/div time: 400us//div ch1 ch2 load transient (1a - 2.4a - 1a) vin=12v, vout=5v ACT4525 - 006 ch1: v out , 200mv/div ch2: i out , 1a/div time: 400us//div ch1 ch2 start up into cc mode ACT4525 - 004 v out = 5.1v r lord = 1.5 i out = 2.65a v in = 12v ch1: v in , 10v/div ch2: v out , 2v/div ch3: i out , 2a/div time: 400s/div ch1 ch2 ch3 output over voltage (5v vout) ACT4525 - 003 ch1: v out , 1v/div ch2: sw, 10v/div time: 1ms/div ch1 ch2 ACT4525 - 001 efficiency (%) load current (ma) 0 500 1000 1500 2000 2500 3000 3500 100 95 90 85 80 75 70 65 60 efficiency vs. load current v in =12v v in =24v
ACT4525 rev1.1, december 17 th , 2015 innovative power tm - 11 - www.active - semi.com copyright ? 2015 active - semi, inc. package outline sop - 8ep pack age outline and dimensions active - semi, inc. reserves the right to modify the circuitry or specifications without notice. users should evaluate each product to make sure that it is suitable for their applications. active - semi products are not intended or authorized for use as critical components in life - support devices or systems. active - semi, inc. does not assume any liability arising out of the use of any product or circuit described in this datasheet, nor does it convey any patent license. active - semi and its logo are trademarks of active - semi, inc. for more information on this and other products, contact sales@active - semi.com or visit http://www.active - semi.com . ? is a registered trademark of active - semi. symbol dimension in millimeters dimension in inches min max min max a 1.350 1.727 0.053 0.068 a1 0.000 0.152 0.000 0.006 a2 1.350 1.550 0.053 0.061 b 0.330 0.510 0.013 0.020 c 0.170 0.250 0.007 0.010 d 4.700 5.100 0.185 0.200 d1 3.202 3.402 0.126 0.134 e 3.734 4.000 0.147 0.157 e1 5.800 6.200 0.228 0.244 e2 2.313 2.513 0.091 0.099 e 1.270 typ 0.050 typ l 0.400 1.270 0.016 0.050 0 8 0 8 e 1 e 2 d 1 b e l c d a a 2 e a 1

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