1 description lt c3623 15v, 5a monolithic synchronous step-down regulator demonstration circuit 2131a is a current mode dc/dc step-down silent switcher ? buck regulator featuring the lt c ? 3623. the board operates from an input range of 4v to 15v , and provides 5a of output current. the output voltage of the demonstration board can be set from 0v to v in C 0.5v . it operates at 1mhz and may be synchronized to an external clock. a soft-start feature controls output voltage slew rate at start-up, reducing current surge and voltage overshoot. a power good output and current monitor signal are provided. discontinuous conduction mode can be selected with a jumper. the demonstration board has options for cable drop compensation, negative output voltage and input voltage regulation. l , lt, ltc, ltm, linear technology, the linear logo and silent switcher are registered trademarks of linear technology corporation. all other trademarks are the property of their respective owners. performance summary this board is suitable for a wide range of battery-powered, point-of-load, ddr memory, thermo electric cooler (tec) systems and other applications. the LTC3623 is available in a low profile, 24-pin qfn package. for other output requirements, see the LTC3623 data sheet. design files for this circuit board are available at http://www.linear.com/demo/dc2131a specifications are at t a = 25c symbol parameter conditions min typ max units v in input supply range 4 15 v v out output voltage jumper selectable 1 5 v i out output current range, continuous 200lfm 0 5 a f sw switching (clock) frequency 1 mhz v out_p-p output ripple v in = 12v, v out = 5v, i out = 5a (20mhz bw) <25 mv pCp i reg output regulation v in : 4v to 15v, a out : 0a to 5a, v out = 1v v in : 4v to 15v, a out : 0a to 5a, v out = 1.5v v in : 4v to 15v, a out : 0a to 5a, v out = 2.5v v in : 4.7v to 15v, a out : 0a to 5a, v out = 3.3v v in : 6.5v to 15v, a out : 0a to 5a, v out = 5v 2 2 2 2 2 % % % % % dc2131afb demo manual dc2131a
2 quick start procedure demonstration circuit 2131a is easy to set up to evalu - ate the performance of the LTC3623. refer to figure 1 for proper measurement equipment setup and follow the procedure below : note : when measuring the output voltage ripple, care must be taken to avoid a long ground lead on the oscilloscope probe. measure the output voltage ripple by touching the probe tip and ground ring directly across the last output capacitor as shown in figure 1. 1. using an input power supply that is capable of 4 v to 15v, set the voltage to 12v. then turn off the supply. 2. with power off, connect the supply to the input terminals +v in and Cv in . a. if effciency measurements are desired, an ammeter capable of measuring 5 a dc or a resistor shunt can be put in series with the input supply in order to measure the dc1722as input current. b. a voltmeter with a capability of measuring at least 15v can be placed across the input terminals in order to get an accurate input voltage measurement. 3. turn on the power at the input. note: make sure that the input voltage never exceeds 15v. 4. check for the proper output voltage which is set using a jumper. setting the jumper to the opt position will set the output voltage to 5v. 5. once the proper output voltage is established, connect a variable load capable of sinking 5 a at 5 v to the output terminals +v out and Cv out . set the current for 0a. a. if effciency measurements are desired, an ammeter or a resistor shunt that is capable of handling 5 a dc can be put in series with the output load in order to measure the dc3623as output current. b. a voltmeter with a capability of measuring at least 5v can be placed across the output terminals in order to get an accurate output voltage measurement. note: if there is no output, temporarily disconnect the load to make sure that the load is not set too high. 6. adjust the load and/or input within the operating range and observe the output voltage regulation, ripple volt - age, effciency and other desired parameters. dc2131afb demo manual dc2131a
3 quick start procedure figure 1. proper measurement equipment setup dc2131afb demo manual dc2131a
4 quick start procedure figure 2. 12v in dcm efficiency figure 3. output ripple at 15v in , 5v out and 5a out (20mv, 500ns/div, 20mhz bandwidth) load current (a) 0.01 1 10 0.1 efficiency (%) 95 90 80 70 85 75 65 60 dc2131a f02 2.5v out 3.3v out 5v out dc2131afb demo manual dc2131a
5 quick start procedure figure 4. transient response waveform at 12v in , 5v out and 2.5 C 5 C 2.5a out (2a, 100mv, 10s/div, 20mhz bandwidth) figure 5. thermal at 12v in , 3.3v out and 5a out , 0lfm dc2131afb demo manual dc2131a
6 item qty reference part description manufacturer/part number required circuit components 1 2 cin1, cin2 cap., 2.2f, x5r, 25v, 10%, 0402 murata., grm155r61e225ke11 2 1 cin3 cap., 10f, x5r, 25v, 10%, 1206 avx., 12063d106kat2a 3 1 cin4 cap., poscap, 22f, 20v, b2 size, tqc series panasonic, 20tqc22myfb 4 1 cout1 cap., 100f, x5r, 10v, 20%, 1210 murata, grm32er61a107me20l 5 2 c1, c3 cap., 0.01f, x5r, 25v, 10%, 0603 avx., 06033d103kat2a 6 2 c4, c5 cap., 0.1f, x7r, 25v, 10%, 0603 avx, 06033c104kat2a 7 1 c6 cap., 4.7f, x5r, 10v, 0603 avx, 0603zd475kat2a 8 1 c7 cap., 1nf, c0g, 25v, 1%, 0603 avx, 06033a102fat2a 9 1 c8 cap., c0g, 100pf, 25v, 5%, 0603 avx, 06033a101jat2a 10 1 l1 ind., pwr 1h, 20% xal60xx series coilcraft, xal6030-102meb 11 1 r1 res., 24.9k, 1/10w, 1%, 0603 vishay, crcw060324k0fkea 12 1 r2 res., 43k, 1/10w, 1%, 0603 vishay, crcw060343k0fkea 13 1 r3 res., 100k, 1/10w, 1%, 0603 vishay, crcw0603100kfkea 14 1 r4 res., 196k, 1/10w, 1%, 0603 vishay, crcw0603200kfkea 15 1 r7 res., 10k, 1/10w, 1%, 0603 vishay, crcw060310k0fkea 16 1 r8 res., 1m, 1/10w, 5%, 0603 vishay, crcw06031m00jnea 17 1 r12 res., 1, 1/10w, 5%, 0603 vishay, crcw06031r00jnea 18 1 r15 res., 33.2k, 1/10w, 1%, 0603 vishay, crcw060333k2fkea 19 1 r16 res., 5.49k, 1/10w, 1%, 0603 vishay, crcw06035k49fkea 20 2 r17, r19 res., 100k, 1/10w, 5%, 0603 vishay, crcw0603100kjnea 21 1 u1 i.c., 15v, 5a monolithic synchronous buck conv linear tech., LTC3623eudd#pbf additional demo board circuit components 22 0 cout2 cap, option 1210 option 23 0 cout3, cout4 cap, option 7343 option 24 0 c9, c10, c11 cap, option 0603 option 25 0 c12 cap, option 1206 option 26 0 d7 diode, option option 27 0 r5, r10, r11, r13, r14, r18, r20, r21, r24, r25 res, option 0603 option 28 4 r6, r9, r22, r23 res., 0, 1/10w, 0603 vishay, crcw06030000z0ea hardware: for demo board only 29 7 e1, e2, e3, e5, e7, e8, e9 test point, turret, 0.094" mtg. hole mill-max, 2501-2-00-80-00-00-07 30 6 jp1, jp2, jp3, jp4, jp5, jp8 conn., header, 1x2, 2mm sullins, nrpn021paen-rc 31 1 jp6 conn., header, 2x3, 2mm sullins, nrpn032paen-rc 32 1 jp7 conn., header, 1x3, 2mm sullins, nrpn031paen-rc 33 4 xjp1, xjp3, xjp4, xjp5 shunt, 2mm samtec, 2sn-bk-g 34 4 (stand-off) stand-off, nylon 0.50" tall keystone, 8833(snap on) parts list dc2131afb demo manual dc2131a
7 information furnished by linear technology corporation is believed to be accurate and reliable. however, no responsibility is assumed for its use. linear technology corporation makes no representa - tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. schematic diagram 5 5 4 4 3 3 2 2 1 1 d d c c b b a a - production hz tim k. 3 5-23-16 10v 10v 10v all resistors and capacitors are in 0603. note: unless otherwise specified 25v dis iset gsns vout ith gsns pgfb intvcc gsns gsns dir pgfb vin vin vin sw intvcc intvcc dir sw intvcc vout intvcc vout vin revision history description d at e approved eco rev revision history description d at e approved eco rev revision history description d at e approved eco rev size date: ic no. rev. sheet of title: approvals pcb des. app eng. technology fax: (408)434-0507 milpitas, ca 95035 phone: (408)432-1900 1630 mccarthy blvd. ltc confidential-for customer use only customer notice linear technology has made a best effort to design a circuit that meets customer-supplied specifications; however, it remains the customer's responsibility to verify proper and reliable operation in the actual application. component substitution and printed circuit board layout may significantly affect circuit performance or reliability. contact linear technology applications engineering for assistance. this circuit is proprietary to linear technology and schematic supplied for use with linear technology parts. scale = none www.linear.com 3 thursday, september 22, 2016 11 15vin, +/- 5a monolithic buck regulator hz tim k. n/a LTC3623eudd demo circuit 2131a size date: ic no. rev. sheet of title: approvals pcb des. app eng. technology fax: (408)434-0507 milpitas, ca 95035 phone: (408)432-1900 1630 mccarthy blvd. ltc confidential-for customer use only customer notice linear technology has made a best effort to design a circuit that meets customer-supplied specifications; however, it remains the customer's responsibility to verify proper and reliable operation in the actual application. component substitution and printed circuit board layout may significantly affect circuit performance or reliability. contact linear technology applications engineering for assistance. this circuit is proprietary to linear technology and schematic supplied for use with linear technology parts. scale = none www.linear.com 3 thursday, september 22, 2016 11 15vin, +/- 5a monolithic buck regulator hz tim k. n/a LTC3623eudd demo circuit 2131a size date: ic no. rev. sheet of title: approvals pcb des. app eng. technology fax: (408)434-0507 milpitas, ca 95035 phone: (408)432-1900 1630 mccarthy blvd. ltc confidential-for customer use only customer notice linear technology has made a best effort to design a circuit that meets customer-supplied specifications; however, it remains the customer's responsibility to verify proper and reliable operation in the actual application. component substitution and printed circuit board layout may significantly affect circuit performance or reliability. contact linear technology applications engineering for assistance. this circuit is proprietary to linear technology and schematic supplied for use with linear technology parts. scale = none www.linear.com 3 thursday, september 22, 2016 11 15vin, +/- 5a monolithic buck regulator hz tim k. n/a LTC3623eudd demo circuit 2131a c3 0.01uf r7 10k r10 (opt) r17 100k r9 0 ohm c6 4.7uf jp8 pgfb l1 1uh jp6 ccm dcm sync mode/sync 1 3 2 4 6 5 r25 opt r18 (opt) cout1 100uf 10v 1210 r243k 1% r24 opt e3 imon e5 pgood c7 1nf r3100k 1% jp1 1.0v u1 LTC3623eudd iset 1 pgood 2 run 3 gsns 4 pvin 5 sw 6 nc 7 mode/sync 8 pgnd 9 pgnd 10 pgnd 11 pgnd 12 vout 13 nc 14 sw 15 pvin 16 svin 17 boost 18 intvcc 19 pgfb 20 imon 21 dir 22 rt 23 ith 24 25 pgnd c10 opt r14 (opt) jp4 3.3v r124.9k 1% r20 (opt) r19 100k r12 1 r13 (opt) jp3 2.5v c5 0.1uf r21 opt e1 vin 4v to 15v c4 0.1uf r4196k 1% e8 vout 2.5v / 5a cin2 2.2uf 25v 0402 jp2 1.5v r8 1m c11 opt e2 gnd c12 opt cin3 10uf 25v 1206 cout2 opt 1210 r5 (opt) jp5 5v r22 0 e9 gnd + cin4 22uf 20v 20tqc22myfb r23 0 r6 0 ohm c8 100pf jp7 on off run 1 3 2 e7 sync + cout4 (opt) d7 opt cin1 2.2uf 25v 0402 r16 5.49k c9 opt + cout3 (opt) r11 (opt) c1 0.01uf r15 33.2k dc2131afb demo manual dc2131a
8 linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax : (408) 434-0507 www.linear.com ? linear technology corporation 2016 lt 1116 rev a ? printed in usa demonstration board important notice linear technology corporation (ltc) provides the enclosed product(s) under the following as is conditions: this demonstration board (demo board) kit being sold or provided by linear technology is intended for use for engineering development or evaluation purposes only and is not provided by ltc for commercial use. as such, the demo board herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods. as a prototype, this product does not fall within the scope of the european union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations. if this evaluation kit does not meet the specifications recited in the demo board manual the kit may be returned within 30 days from the date of delivery for a full refund. the foregoing warranty is the exclusive warranty made by the seller to buyer and is in lieu of all other warranties, expressed, implied, or statutory, including any warranty of merchantability or fitness for any particular purpose. except to the extent of this indemnity, neither party shall be liable to the other for any indirect, special, incidental, or consequential damages. the user assumes all responsibility and liability for proper and safe handling of the goods. further, the user releases ltc from all claims arising from the handling or use of the goods. due to the open construction of the product, it is the users responsibility to take any and all appropriate precautions with regard to electrostatic discharge. also be aware that the products herein may not be regulatory compliant or agency certified (fcc, ul, ce, etc.). no license is granted under any patent right or other intellectual property whatsoeve r. ltc assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind. ltc currently services a variety of customers for products around the world, and therefore this transaction is not exclusive. please read the demo board manual prior to handling the product. persons handling this product must have electronics training and observe good laboratory practice standards. common sense is encouraged. this notice contains important safety information about temperatures and voltages. for further safety concerns, please contact a ltc application engineer. mailing address: linear technology 1630 mccarthy blvd. milpitas, ca 95035 copyright ? 2004, linear technology corporation dc2131afb demo manual dc2131a
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