ev2905-k-01a 1.2v, 10a, 300khz, hysteretic synchronous step-down controller evaluation board ev2905-k-01a rev. 1.0 www.monolithicpower.com 1 12/7/2017 mps proprietary information. unaut horized photocopy and duplication prohibited. preliminary specifications subject to change ? 2017 mps. all rights reserved. the future of analog ic technology description the ev2905-k-01a is the evaluation board for the MP2905EK, a hysteretic synchronous step- down controller. it offers a very compact solution to achieve 1.2v, 10a continuous output current from a 10.8v to 13.2v input voltage range over a wide operation input voltage. an adjustable soft-start prevents inrush current at turn-on. hysteretic voltage control can provide fast transient without any loop compensation. full protection features include ocp, output ovp, thermal shut down. the ev2905-k-01a frequency is approximately 300khz (12v input). peak current limit is set at 15a. the efficiency is up to 90% (12v input) with the supplied components. electrical specifications parameter symbol value units input voltage v in 10.8 - 13.2v v output voltage v out 1.2 v load current i out 10 (1) a features ? 10a output current,1.2v output voltage ? programmable soft-start ? hiccup current limit and thermal shutdown ? monotonic startup into prebias output ? startup overvoltage protection ? enable/shutdown applications ? motherboard power supplies ? agp and pci-express power supplies ? graphic-card power supplies ? set-top boxes ? point-of-load power supplies notes: 1) circuit can work up to about 10a over a wide input voltage range. this evb shows the performance at 12v input. so the frequency and curren t limit are designed for the 12v application ?mps? and ?the future of analog ic technology? are registered trademarks of monolithic power systems, inc. ev2905-k-01a evaluation board (l x w x h) 2.5? x 2.5? x 0.63? (6.3cm x 6.3cm x 1.6cm) board number mps ic number ev2905-k-01a MP2905EK efficiency v in =12v, v out =1.2v 0 10 20 30 40 50 60 70 80 90 100 i out (a) 0246810
ev2905-k-01a hysteretic synchronous step-down controller ev board ev2905-k-01a rev. 1.0 www.monolithicpower.com 2 12/7/2017 mps proprietary information. unaut horized photocopy and duplication prohibited. preliminary specifications subject to change ? 2017 mps. all rights reserved. evaluation board schematic z r6 0 r7 20k r5 ns r4 ns q3 4.7uf c9 r10 r9 0 r11 r8 0 d2 0520 c10 r13 c11 ns r12 c1d 0.1uf c6 1uf c12 ns c13 ns 330uf c2d 0.1uf 3k 0.82uh
ev2905-k-01a hysteretic synchronous step-down controller ev board ev2905-k-01a rev. 1.0 www.monolithicpower.com 3 12/7/2017 mps proprietary information. unaut horized photocopy and duplication prohibited. preliminary specifications subject to change ? 2017 mps. all rights reserved. ev2905-k-01a bill of materials qty refdes value description package manufacturer manufacturer p/n 2 c1a,c1b 22f ceramic cap, x5r, 25v 1210 murata grm32er61e226ke15l 2 c2a,c2b 22f ceramic cap, x5r, 16v 1210 murata grm32er61c226ke20l 1 c2c 330f poscap, 6.3v poscap sanyo 6tpe330mil 2 c1d,c2d 0.1f ceramic cap, x7r, 25v 0603 murata grm188r71e104ka01d 2 c3,c5 10nf ceramic cap, x7r, 50v 0603 murata grm188r71h103ka01d 1 c4 4.7f ceramic cap, x5r, 6.3v 0603 murata grm188r60j475ke19d 1 c6 1f ceramic cap, x7r, 25v 0603 murata grm188r71e105ka12d 1 c7 0.1f ceramic cap, x7r, 50v 0603 murata grm188r71h104ka93d 1 c8 3.9nf ceramic cap, x7r, 50v 0603 murata grm188r71h392ka01d 1 c9 2.2nf ceramic cap, x7r, 50v 0603 murata grm1885r71h222a01d 1 c10 2.2f ceramic cap, x7r, 10v 0603 murata grm188r71a225ke15d c11 ns c12,c13 ns 1 r1 1.05k ? film res, 1% 0603 royal rl0603fr-071k05l 1 r2 1k ? film res, 1% 0603 royal rl0603fr-071kl 1 r3 3k ? film res, 1% 0603 royal rl0603fr-03kl r4,r5 ns 4 r6,r8 r9,r11 0 ? film res, 1% 0603 yageo rc0603fr-070rl 1 r7 20k ? film res, 1% 0603 royal rl0603fr-0720kl 2 r10,r12 2 ? film res, 1% 0603 yageo rl0603fr-072rl 1 r13 52.3k ? film res, 1% 0603 royal rl0603fr-0752k3l 1 d1 b0540w,40v,0.5a sod123 diodes b0540w 1 d2 b0520lw-7- f,20v,0.5a sod323 diodes b0520lw-7-f 1 l1 0.82h inductor,rated current=27a,saturation current=35a,dcr=0.9 m ? smt wruth 744355182 2 q1,q2 am7432n,30v,27a,rd s_on=4.9m ? @4.5vgs, qg=25nc,tr=13ns,tf=43 ns@4.5vgen powerpak so-8 analog power am7432n 1 q3 2n7002(60v,115ma) sot-23 diodes 2n7002(60v,115ma) 1 u1 mp2905 synchronous step-down controller msop10 mps MP2905EK
ev2905-k-01a hysteretic synchronous step-down controller ev board ev2905-k-01a rev. 1.0 www.monolithicpower.com 4 12/7/2017 mps proprietary information. unaut horized photocopy and duplication prohibited. preliminary specifications subject to change ? 2017 mps. all rights reserved. printed circuit board layout figure 1?top silk layer figure 2?top layer figure 3?inner 1 layer figure 4?inner 2 layer figure 5?bottom layer
ev2905-k-01a hysteretic synchronous step-down controller ev board notice: the information in this document is subject to change wi thout notice. users should warra nt and guarantee that third party intellectual property rights are not infringed upon w hen integrating mps products into any application. mps will not assume any legal responsibility for any said applications. ev2905-k-01a rev. 1.0 www.monolithicpower.com 5 12/7/2017 mps proprietary information. unaut horized photocopy and duplication prohibited. preliminary specifications subject to change ? 2017 mps. all rights reserved. quick start guide 1. stuff multi-strand wire in vout, vout_gnd pad and single strand wire in vin, vin_gnd pad. 2. connect the positive terminal of the load to vo ut multi-strand wire, and the negative terminal of the load to gnd multi-strand wire. 3. preset the power supply output to 12v and turn it off. 4. connect the positive terminal of the power supply output to the vin wire and the negative terminal of the power supply output to the gnd wire. 5. connect the en pin to gnd. 6. turn the power supply on. the MP2905EK will automatically startup. 7. to use the enable function, drive en higher than 4v to turn on the mos q3, then ss is pulled down, part shuts down. drive en less than 0.5v to turn off the mos q3, then ss is released, part turns on. do not float en pin. 8. the output voltage vout can be programmed by r1 and r2. calculate the new value using the formula: ) 1 ( 2 1 ? ? ? fb out v v r r where v fb =0.59v. in order to get good transient, r1 and r2 should be small enough. always set r2=1k ? or smaller, and r1 is not higher than 3 k ? . 9. the frequency is set by c9 and r13. c9 should not be small enough to get good transient response, 2.2nf is recommended , then r13 is used to program the frequency by formula below: hy in out in in out in out v c v v ns v ns v f v v v r ? ? ? ? ? ? ? ? ? ? 9 13 ) 20 90 ( ) ( where v hy is output regulation hysteresis, typical value is 22mv. 10. the ev board is designed for 12v input, 1.2vout application. so, for other application, some parameters such as current limit and frequency need to be redesigned. please refer to an023 to set related parameters.
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