1 / 6 MA5602 ( preliminary) major power technology co., ltd. rev.0. 5 apr . 0 8 , 201 4 38v synchronous buck converter with cc/cv ? general description MA5602 is a wide input voltage, high efficiency active cc step - down dc/dc converter that operates in either cv ( constant output voltage) mode or cc ( constant output current) mode. MA5602 provi des up to 2.5 a output current at 18 0khz switching frequency. current mode control provides fast transient response and cycle - b y - cycle current limit. an internal soft - start prevents inrush current at turn - on, this device, available in an so p 8l - ep(exposed p ad) package, provides a very compact solution with minimal external components. ? features - wide 8 v to 38 v operating input range - integrated 1 4 0m power mosfet switches - output adjustable from vfb( 1 .0 v) to 5.5 v - up to 9 2 % efficiency - internal soft - start . - stable with low esr ceramic output capacitors - fixed 180 khz frequency - cycle - by - cycle over current protection - input under voltage lockout ? application circuit v out =v fb (1+ r1/r2 ) , v fb = 1.00 v, r2 suggest 10k~30 k i sen = v set / rsen - i/2 P 1 2 0mv / 50 m - 0.2a = 2. 2 a
2 / 6 MA5602 ( preliminary) major power technology co., ltd. rev.0. 5 apr . 0 8 , 201 4 ? pin assignment the package of MA5602 is so p8l - ep(exposed pad) ; the pin assignment is given by : name description bs boot - strap pin. supply high side gate driver. dec ouple this pin to lx pin with 24 ohm + 0.1uf ceramic cap. in power input. in supplies the power to the ic, as well as the step - down converter switches. drive in with a 8 v to 38 v power source. bypass in to gnd with a suitably large capacitor to eliminate no ise on the input to the ic. see input capacitor . sw power switching output. sw is the switching node that supplies power to the output. connect the output lc filter from sw to the output load. gnd ground. pad ground ( connect to gnd) . fb feedback input . fb senses the output voltage to regulate that voltage. drive fb with a resistive voltage divider from the output voltage. comp compensation node. comp is used to compensate the regulation control loop. connect a series rc network from comp to gnd to co mpensate the regulation control loop. sen + the current sense i nput ( +) pin. sen - the current sense i nput ( - ) pin. ? rder/marking information order information top marking
3 / 6 MA5602 ( preliminary) major power technology co., ltd. rev.0. 5 apr . 0 8 , 201 4 ? b lock d iagram internal power pwm control & protect logic fb m 1 m 2 current sense amplifier bs in sw gnd input uvlo 7 . 0 v softstart thermal protection 1 v 1 . 1 v sen + sen - vdd comp ? a bsolute maximum ratings ( at t a =25 c ) characteristics symbol rating unit supply voltage v in C 0.3 to + 42 v switch node voltage v sw C 0.3 to v in + 0.3 v boost voltage v bs vsw C 0.3 to vsw + 6 v all other pins C 0.3 to +6 v lead temperature 260 c storage temperature C 65 to +150 c junction temperature t j 150 c output voltage v out vfb to 6 v ambient operating temperature C 40 to +85 c thermal resistance from junction to case jc 15 c/w thermal resistance from junction to ambient ja 40 c/w note : ja is measured with the pcb copper area of approximately 1 in 2 ( multi - layer). that need connect to exposed pad.
4 / 6 MA5602 ( preliminary) major power technology co., ltd. rev.0. 5 apr . 0 8 , 201 4 ? e lectrical c haracteristics ( v in = 12v, t a = +25c, unless other wise noted. ) characteristics symbol conditions min typ max units input voltage range 8 - 38 v quiescent current i ccq v fb = 1.0 5 v - 0.7 1. 4 ma feedback voltage v fb 8 v v in 38 v 0.9 8 1 . 00 1.02 v feedback overvoltage threshold ovp ( fb) - 1.1x - v fb h igh - side switch on resistance ( note ) r ds(on)1 - 1 5 0 - m low - side switch on resistance ( note ) r ds(on)2 - 1 4 0 - m high - side switch leakage current v fb = 1.0 5 v, v sw = 0v - - 10 a upper switch current limit minimum duty cycle 2.9 3 . 5 - a lower switch current limit from drain to source - 0 . 7 - a oscillation frequency f osc1 - 18 0 - khz short circuit oscillation frequency f osc2 v fb =<0.5 v - 7 0 - khz maximum duty cycle d max - 90 - % minimum on time ( note ) t on(min) - 220 - ns sense voltage v sen ( v sen +) - ( v sen - ) 114 1 2 0 1 2 6 mv v in ovp turn - off voltage input voltage rising - 40 - v v in ovp hysteresis input voltage falling - 6 - v input under voltage lockout threshold uvlo v in rising 6.5 7.0 7.5 v input under voltage lockout threshold hysteres is uvlo - hys - 8 0 0 - mv soft - start period - 3 - ms thermal shutdown t sd - 1 5 0 - c thermal shutdown hysterisis t sh - 30 - c note : guaranteed by design.
5 / 6 MA5602 ( preliminary) major power technology co., ltd. rev.0. 5 apr . 0 8 , 201 4 ? function descriptions the MA5602 is a synchronous rectified, current - mode, step - down regulator. it regulates input voltages from 8 v to 38 v down to an output voltage as low as v fb , and supplies up to 2 . 5 a of load current. the MA5602 uses current - mode control to regulate the output voltage. the output voltage is measured at fb through a res istive voltage divider and amplified through the internal tran conductance error amplifier. the converter uses internal n - channel mosfet switches to step - down the input voltage to the regulated output voltage. since the high side mosfet requires a gate vo ltage greater than the input voltage, a boost capacitor connected between sw and bs is needed to drive the high side gate. the boost capacitor is charged from the internal 5v rail when sw is low. when the MA5602 fb pin exceeds 1 0% of the nomi nal regulation voltage of v fb , the over voltage comparator is tripped and the comp pin is discharged to gnd, forcing the high - side switch off. ? application information component selection setting the output voltage the output voltage is set using a resistive voltage d ivider from the output voltage to fb pin. the voltage divider divides the output voltage down to th e feedback voltage by the ratio . thus the output voltage is: v out = v fb 2 2 1 r r r ? for example, v fb =1.00v for a 5.0 v output voltage, r2 is 10k, and r1 is 40 k. inductor selection the inductor is required to supply constant current to the output load while being driven by the switched input voltage. a larger value inductor will result in less ripple current that will result in lower output ripple voltage. however, the larger value inductor will have a larger physical size, higher series resistance, and/or lower saturation current. a good rule for determining the inductance to use is to allow the peak - to - peak ripple cu rrent in the inductor to be approximately 30% of the maximum switch current limit. vin <24v <28v <34v inductor 47 uh 33uh 22uh the choice of which style inductor to use mainly depends on the price vs. size requirements and any emi requirements.
6 / 6 MA5602 ( preliminary) major power technology co., ltd. rev.0. 5 apr . 0 8 , 201 4 ? packa ge outlines detail a l h e a a 2 a 1 e d 7 ( 4 x ) b y c detail a y x expose pad symbol dimensions in millimeters dimensions in inches min. nom. max. min. nom. max. a - - 1.75 - - 0.069 a1 0 - 0.15 0 - 0.06 a2 1.25 - - 0.049 - - c 0.1 0.2 0.25 0.0075 0.008 0.01 d 4.7 4.9 5.1 0.185 0.19 3 0.2 e 3.7 3.9 4.1 0.146 0.154 0.161 h 5.8 6 6.2 0.228 0.236 0.244 l 0.4 - 1.27 0.015 - 0.05 b 0.31 0.41 0.51 0.012 0.016 0.02 e 1.27 bsc 0.050 bsc y - - 0.1 - - 0.004 x - 2.34 3.33 - 0.092 0.131 y - 2.34 2.54 - 0.092 0.10 0 o - 8 o 0 o - 8 o mold flash shall not exceed 0.25mm per side jedec outline: ms - 012 ba
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