ev9942-j-00a high efficiency 2a, 36v, 410khz sync. step-down switch evaluation board with power good ev9942-j-00a rev. 1.0 www.monolithicpower.com 1 8/27/2014 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2014 mps. all rights reserved. the future of analog ic technology description the mp9942 is a high-frequency, synchronous, rectified, step-down, switch-mode converter with built-in power mosfets. it offers a very compact solution to achieve a 2a continuous output current with excellent load and line regulation over a wide input supply range. the mp9942 has synchronous mode operation for higher efficiency over the output current load range. current-mode operation provides fast transient response and eases loop stabilization. full protection features include over-current protection and thermal shut down. the mp9942 requires a minimal number of readily-available standard external components, and is available in a space-saving 8-pin tsot23 package. electrical specifications (1) parameter symbol value units continuous 12 v input voltage transient 36 v output voltage v out 3.3 v output current i out 0-2 a notes: 1) for different input/output voltage specs and different output capacitor/inductor may need cha nge the application circuit parameters. features ? wide 4v to 30v continuous operating input range ? 36v input transient tolerance ? 90m ? /55m ? low r ds(on) internal power mosfets ? high-efficiency synchronous mode operation ? 410khz switching frequency ? synchronizes from 200khz to 2.2mhz external clock ? high duty cycle for automotive cold-crank ? internal power-save mode ? internal soft-start ? power good indicator ? over-current protection with hiccup ? thermal shutdown ? output adjustable from 0.8v ? available in an 8-pin tsot23 package packageapplications ? automotive ? industrial control system ? distributed power systems all mps parts are lead-free and adhere to the rohs directive. for mps green status, please visit mps website under products, quality assurance page. ?mps? and ?the future of analog ic technology? are registered trademarks of monolithic power systems, inc. typical application (l x w x h) 6.3cm x 4.9cm x 1.3cm board number mps ic number ev9942-j-00a MP9942GJ 0 10 20 30 40 50 60 70 80 90 100 load current(ma) efficiency vs. load current v out =3.3v 1 10 100 1000 10000 v in =12v v in =24v v in =28v
ev9942-j-00a ?2a, 36v high efficien cy synchronous step down converter ev9942-j-00a rev. 1.0 www.monolithicpower.com 2 8/27/2014 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2014 mps. all rights reserved. evaluation board schematic 10uf c1a 50v 0.1uf c8 50v 1m r5 ns r6 0.1uf c4 20 r4 10uh l1 22uf c2a 41.2k r1 3.3v/2a ns r3 13k r2 10 r10 51k r9 ns c3 16v vin en vout gnd 10uf c1b 50v 0.1uf c6 100k r7 pg 22uf c2 16v gnd sw 6 en/sync 3 in 7 fb 1 vcc 2 bst 4 gnd mp9942 pg 8 u1 5
ev9942-j-00a ?2a, 36v high efficien cy synchronous step down converter ev9942-j-00a rev. 1.0 www.monolithicpower.com 3 8/27/2014 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2014 mps. all rights reserved. ev9942 bill of materials qty ref value description package manufacturer manufacturer p/n 2 c1a, c1b 10 f ceramic cap., 50v, x7r 1210 murata grm32er71h106ka12l 1 c8 0.1 f ceramic cap., 50v, x5r 0603 murata grm188r71h104ka93d 2 c2,c2a 22 f ceramic cap., 16v, 20%, x5r 1206 murata grm32er71c226ke79 1 c3 ns 1 c4 0.1 f ceramic cap., 50v, x5r 0603 murata grm188r71h104ka93d 1 c6 0.1 f ceramic cap., 50v, x5r 0603 murata grm188r71h104ka93d 1 r1 41.2k thick film res., 1% 0603 yageo rc0603fr-0741k2l 1 r2 13k thick film res., 1% 0603 yageo rc0603fr-0713kl 1 r3 ns 1 r4 20 ? thick film res., 1% 0603 yageo rc0603fr-0720rl 1 r5 1m thick film res., 1% 0603 yageo rc0603fr-071ml 0 r6 ns 1 r7 100k thick film res., 1% 0603 yageo rc0603fr-07100kl 1 r9 51k thick film res., 1% 0603 yageo rc0603fr-0751kl 1 r10 10 ? thick film res., 1% 0603 yageo rc0603fr-0710rl 1 l1 10 h inductor, dcr=33m ? , is=4a smd wurth 744314101 1 u1 MP9942GJ synchronous step- down converter tsot23- 8 mps MP9942GJ
ev9942-j-00a ?2a, 36v high efficien cy synchronous step down converter ev9942-j-00a rev. 1.0 www.monolithicpower.com 4 8/27/2014 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2014 mps. all rights reserved. evb test results performance waveforms are tested on the evaluation board. v in = 12v, v out = 3.3v, l = 10h, r bst =20 ? , t a = +25c, unless otherwise noted.
ev9942-j-00a ?2a, 36v high efficien cy synchronous step down converter ev9942-j-00a rev. 1.0 www.monolithicpower.com 5 8/27/2014 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2014 mps. all rights reserved. evb test results (continued) performance waveforms are tested on the evaluation board. v in = 12v, v out = 3.3v, l = 10h, r bst =20 ? , t a = +25c, unless otherwise noted.
ev9942-j-00a ?2a, 36v high efficien cy synchronous step down converter ev9942-j-00a rev. 1.0 www.monolithicpower.com 6 8/27/2014 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2014 mps. all rights reserved. evb test results (continued) performance waveforms are tested on the evaluation board. v in = 12v, v out = 3.3v, l = 10h, r bst =20 ? , t a = +25c, unless otherwise noted.
ev9942-j-00a ?2a, 36v high efficien cy synchronous step down converter ev9942-j-00a rev. 1.0 www.monolithicpower.com 7 8/27/2014 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2014 mps. all rights reserved. printed circuit board layout ? ? figure 1?top silk layer figure 2?top layer ? figure 4?bottom layer
ev9942-j-00a ?2a, 36v high efficien cy synchronous step down converter notice: the information in this document is subject to change wi thout notice. please contact m ps for current specifications. users should warrant and guarantee that third party intellectual property rights ar e not infringed upon when integrating mps products into any application. mps will not assume any legal responsibility for any said applications. ev9942-j-00a rev. 1.0 www.monolithicpower.com 8 8/27/2014 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2014 mps. all rights reserved. quick start guide 1. connect the positive and negative terminals of the load to the vout and gnd pins, respectively. 2. preset the power supply output between 4v and 30v, and then turn off the power supply. 3. connect the positive and negative terminals of the power supply output to the vin and gnd pins, respectively. 4. turn the power supply on. the mp9942 will automatically startup. 5. to use the enable function, apply a digital input to the en pin. drive en higher than 1.4v to turn on the regulator or less than 1.25v to turn it off. 6. to use the external synchronous function to adjust the switching frequency, apply an external clock signal to en/sync pin.
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