EVNB679 26v, low iq, high current, fixed 5.5v-8a synchronous buck converter with 100ma ldo preliminary specifications subject to change EVNB679 rev. 1.0 www.monolithicpower.com 1 11/14/2014 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. preliminary specifications subject to change ? 2014 mps. all rights reserved. the future of analog ic technology description the nb679 is a fully integrated high frequency synchronous rectified step-down switch mode converter with fixed 5v vout. it offers very compact solution to achieve 8a continuous output current and 10a peak output current over a wide input supply range with excellent load and line regulation. the nb679 operates at high efficiency over a wide output current load rang based on mps proprietary switching loss reduction tech and internal low ron power mosfets adaptive constant-on-time (cot) control mode provides fast transient response and eases loop stabilization. the dc auto tune loop provides good load and line regulation. nb679 also provide fixed 5v ldo which can be used to power the external peripheries. full protection features include oc limit, ovp, uvp and thermal shut down. the converter requires minimum number of external components and is available in qfn 2x3 packages. features ? wide 5.5v to 26v operating input range ? fixed 5v vout, support 5.5v-5v ? ultrasonic mode ? 100 a low quiescent current ? 8a continous output current ? 10a peak output current ? adaptive cot for fast transient ? dc auto tune loop ? stable with poscap and ceramic output ? built-in 5v, 100ma ldo with switch over ? 1% reference voltage ? internal soft start ? output discharge ? 700khz switching frequency ? ocp, ovp, uvp(metal hiccup) protection and thermal shutdown. ? latch off reset via en or power cycle. applications ? notebook systems and tablet pc ? networking systems and server ? personal video recorders ? distributed power systems EVNB679-d-00a evaluation board (l x w ) 635mm x 635mm board number mps ic number EVNB679-d-00a nb679 output current(a) 60 70 80 90 100 0.001 0.01 0.1 1 10 v in =19v v in =12v v in =8.4v v in =5.5v 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 o f monolithic power systems, inc.
EVNB679, synchronous 5vout st ep-down converter ev board preliminary specifications subject to change EVNB679 rev. 1.0 www.monolithicpower.com 2 11/14/2014 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. preliminary specifications subject to change ? 2014 mps. all rights reserved. evaluation board schematic vcc vcc pg pg sw sw en en enldo enldo ldo ldo gnd3 gnd gnd4 gnd gnd5 gnd gnd6 gnd vin_sense vin vout_sense vout 100nf c1c gnd vin 1.5uh l1 3.3 r3 100nf c2b vout gnd vout gnd gnd ldo 100k r7 agnd gnd 1.5m r1 ns r2 4.7uf c4 pg vcc agnd pgnd sw en bst nb679 bst 8 sw 7 nc 4 vout 5 pgnd 2 agnd 10 vcc 9 pg 3 vin 1 ldo 6 enldo 12 en 11 u1 vout 22uf c1a 22uf c1b 22uf c2c 22uf c2d 22uf c2e 22uf c2f ns c2a 220nf c3 ns r4 100nf c7 1uf c5 ns c2g ns c9 ns r8 100uf cin-optional gnd agnd 2 1 etch etch vin enldo the agnd should be separate to pgnd in all the conditions unless they are finally connected together to vcc cap
EVNB679, synchronous 5vout st ep-down converter ev board preliminary specifications subject to change EVNB679 rev. 1.0 www.monolithicpower.com 3 11/14/2014 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. preliminary specifications subject to change ? 2014 mps. all rights reserved. EVNB679 bill of materials qty ref value description package manufacture manufacture_pn 2 c1a, c1b 22 f ceramic capacitor;25v;x5 r 1206 murata grm21br61e226ke15 2 c1c, c2b 100nf ceramic capacitor;50v;x7 r 0603 murata grm188r71h104ka93d 6 c2a, c2g, c9, r2, r4, r8 ns 4 c2c, c2d, c2e, c2f 22 f ceramic capacitor;6.3v;x 5r 0805 murata grm21br60j226me39l 1 c3 220nf capacitor;16v;x5 r 0402 murata grm155r71c224ka12d 1 c4 4.7 f capacitor;6.3v;x 5r 0402 tdk c1005x5r0j475m 1 c5 1 f ceramic capacitor;25v;x7 r 0402 murata grm155r61e105ka12 1 c7 100nf ceramic capacitor;50v;x7 r 0402 tdk c1005x7r1c104k 1 cin-option al 100 f capacitor;25v smd 12 en, enldo, gnd, gnd, gnd, gnd, ldo, pg, sw, vcc, vin_sense, vout_sen se connector connector,1mm 4 gnd, gnd, vin, vout connector connector,2mm 1 l1 1.5 h inductor;1.5uh;10 m;14a smd wurth 744311150 1 r1 1.5m resistor;1%; 0402 yageo rc0402fr-071m5l 1 r3 3.3 film resistor ;5% 0603 yageo rc0603jr-073r3l 1 r7 100k film resistor;5% 0402 cyntec rr0510s-1003-jn 1 u1 nb679 nb679 qfn2*3 mps nb679
EVNB679, synchronous 5vout st ep-down converter ev board preliminary specifications subject to change EVNB679 rev. 1.0 www.monolithicpower.com 4 11/14/2014 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. preliminary specifications subject to change ? 2014 mps. all rights reserved. printed circuit board layout figure 1?top layer and silk figure 2?inner layer 1 figure 3?inner layer 2 figure 4?bottom layer
EVNB679, synchronous 5vout st ep-down converter ev board preliminary specifications subject to change 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. EVNB679 rev. 1.0 www.monolithicpower.com 5 11/14/2014 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. preliminary specifications subject to change ? 2014 mps. all rights reserved. quick start guide 1. connect the positive and negative terminals of t he load to the vout and gnd pins, respectively. 2. preset the one power supply output between 5.5v and 24v as vin, 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 vin power supply on. the nb679 will automatically startup. 5. to use the enable function, apply a digital input to the en pin. drive en higher than 2v to turn on the regulator or less than 0.4v to turn it off.
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