1 description lt c3892-2, 60v, low i q multiphase synchronous step-down converter demonstration circuit 2493a is a high output voltage capable, high efficiency synchronous polyphase ? buck converter featuring the lt c ? 3892euh-2. the dc2493a has a wide input voltage range from 16v to 55v, and is capable of delivering up to 30a of output current. the output voltage of the dc2493a is set to 12v , however, the output voltage can go as high as 55v, with certain modifications. the dc2493 a supports three operation modes: fixed-frequency modulation, pulse-skipping mode and burst mode ? operation. fixed-frequency mode of operation reduces output voltage ripple, and yields a low noise switching spectrum. burst mode operation employs a variable frequency switching algorithm that minimizes the input quiescent current and improves efficiency at light loads. l , lt, ltc, ltm, linear technology, polyphase, burst mode and the linear logo are registered trademarks of linear technology corporation. all other trademarks are the property of their respective owners. p erformance s ummary the dc2493 a consumes less than 5a of quiescent cur- rent during shutdown and it consumes less than 1ma at a no load condition in burst mode operation. the dc2493a has a standard operating frequency of 150khz, but can be adjusted to frequencies as high as 900khz . the dc2493 is a dual phase step-down converter ; however it designed to be easily transformed to a 4- or 6-phase system by combining two or three dc2493a boards. the LTC3892-2 data sheet gives a complete description of these parts, operation, and application information and must be read in conjunction with this quick start guide for demonstra - tion circuit 2493a. design files for this circuit board are available at http://w ww.linear.com/demo/dc2493a specifications are at t a = 25c parameter conditions value units minimum input voltage 16 v maximum input voltage 55 v output voltage v out regulation v in = 16v C 55v 12 2% v maximum continuous output current 30 a preset operating frequency r_prg = 31.6k 150 khz external clock sync frequency range 75 to 850 khz efficiency v in = 24v, v out = 12v, i out = 15a see figures 3, 4 efficiency curves for complete operating range 97 % t ypical output ripple vout v in = 36v, iout = 15a (20mhz bw) < 35 mv p-p quiescent current at shut-down v in = 16v C 55v < 7 a input current at no load v in = 16v C 55v < 100 a dc2493af demo manual dc2493a
2 quick s tart p roce d ure demonstration circuit 2493a is easy to set up to evaluate the performance of the LTC3892-2. for proper measurement equipment configuration, set up the circuit according to the diagram in figure 1. before proceeding to test, insert shunt jp2 (run) into off position, which connects the run pin to ground (gnd), and thus, shut-down the circuit. note: when measuring the input or output voltage ripple, care must be taken to avoid a long ground lead on the oscilloscope probe. measure the input or output voltage ripple by touching the probe tip directly across the v in or v out and gnd terminals. see figure 2 for proper scope probe technique. 1. with the dc2394 set up according to the proper mea - surement and equipment in figure 1, apply 20v at v in . measure v out ; it should read 0v. if desired, one can measure the shutdown supply current at this point. the supply current will be approximately 5a, or less, in shutdown. 2. turn on the cir cuit by inserting the shunt in header jp2 (run) into the on position. the output voltage should be regulating. measure v out it should measure 12v 2% (do not apply more than the rated maximum volt - age of 55v to the board or the part may be damaged). 3. var y the converter load, which should not exceed 30a. note: all four input and output terminals v in , v out and two gnd equipped with two banana jacks, two-wires can be used for each terminal to reduce copper looses and heat dissipation in the interconnection lines. 4. var y the input voltage from 16v to 55v; v out should measure 12v 2%. 5. se t output current to zero and move jumper jp1 (mode) into burst mode position and measure v out ; it should register 12v 2%. 6. se t output current to zero and move jumper jp2 (mode) into pls skip position and measure v out ; it should register 12v 2%. figure 1. proper measurement equipment setup dc2493af demo manual dc2493a
3 quick s tart p roce d ure figure 3. efficiency vs load current, light loads figure 4. efficiency vs load current figure 2. measuring input or output ripple gnd vin load current (a) 0 efficiency (%) 96.5 96.0 95.0 94.0 95.5 94.5 93.5 93.0 92.5 1 dc2493a f03 2 0.5 1.5 24v in 48v in load current (a) 5 efficiency (%) 98.5 98.0 97.0 96.0 97.5 96.5 95.5 95.0 94.5 15 dc2493a f04 30 10 20 25 24v in 48v in dc2493af demo manual dc2493a
4 quick s tart p roce d ure figure 5. thermal map, v in 24v, i o 30a, no air flow, t a = 25c figure 6. thermal map, v in 48v, i o 30a, no air flow, t a = 25c dc2493af demo manual dc2493a
5 p arts list item qty reference part description manufacturer/part number required circuit components 1 5 c1, c14, c15, c16, c17 cap, 1210 2.2f 10% 100v x7r murata grm32er72a225ka35 2 1 c2 cap, 56f 20% 63v hybrid alum elec panasonic eehza1j560p 3 2 c3, c33 cap, 0805 0.1f 10% 100v x7r murata grm21br72a104kac4l 4 2 c4, c51 cap, 0805 2.2f 10% 25v x7r murata grm21br71e225ka73l 5 1 c5 cap, 0603 0.1f 10% 50v x7r murata grm188r71h104ka93d 6 2 c6, c8 cap, 0603 47pf 5% 100v npo murata grm1885c2a470ja01d 7 1 c7 cap, 0603 10pf 5% 50v c0g murata grm1885c1h100ja01d 8 1 c9 cap, 0603 6.8nf 10% 50v x7r murata grm188r71h682ka01d 9 1 c11 cap, 0603 0.1f 10% 100v x7r murata grm188r72a104ka35d 10 2 c12, c13 cap, 0603 220pf 5% 100v c0g murata grm1885c2a221ja01d 11 2 c18, c27 cap, 0603 1f 10% 16v x7r murata grm188r71c105ka12d 12 2 c20, c25 cap, 150f 20% 16v alum panasonic 16svpc150m 13 4 c21, c22, c23, c24 cap, 1206 10f 10% 16v x7r murata grm31cr71c106kac7l 14 2 c30, c31 cap, 0603 0.22f 10% 25v x5r murata grm188r61e224ka88d 15 4 c41, c42, c43, c44 cap, 0805 0.1f 10% 100v x7r opt murata grm21br72a104kac4l opt 16 2 l1, l2 ind, 6.8h coilcraft ser2918h-682kl 17 2 q1, q3 xstr, mosfet n-ch 80v 49a tdson-8 infineon bsc117n08ns5 18 2 q6, q7 xstr, mosfet n-ch 80v 100a tdson-8 infineon bsc026n08ns5 19 2 rs1, rs2 res, 2010 0.001 1% 1w vishay wsl20101l000fea18 20 1 r_prg res, 0603 31.6k 1% 1/10w vishay crcw060331k6fkea 21 1 r1 res. 1206 2.2 1% 1/4w vishay crcw12062r20fkea 22 10 r3, r7, r10, r12, r16, r17, r18, r27, r28, r36 res, 0603 0 jumper vishay crcw06030000z0ea 23 3 r8, r31, r32 res, 0603 100k 5% 1/10w vishay crcw0603100kjnea 24 1 r9 res, 0805 499k 1% 1/8w vishay crcw0805499kfkea 25 1 r11 res, 0603 35.7k 1% 1/10w vishay crcw060335k7fkea 26 1 r14 res, 0603 9.76k 1% 1/10w vishay crcw06039k76fkea 27 2 r19, r20 res, 0603 100 5% 1/10w vishay, crcw0603100rjnea 28 1 r30 res, 0603 90.9k 1% 1/10w vishay crcw060390k9fkea 29 1 u1 ic, dual output high voltage step-down converter linear technology ltc3892euh-2#pbf additional demo board circuit components 31 5 c28, c29, c32, c34 , c35 cap , 0603 op tion option 32 4 c45, c46, c48, c50 cap, 1206 option option 33 3 c40, c47, c49 cap, elec option option 34 4 q2, q4, q5, q8 xstr, option option 35 2 rs3, rs4 res, 2010 option option 36 7 r2, r4, r5, r13, r21, r22, r23 res, 0603 option option 37 6 r24, r25, r26, r29, r33, r34, res, 0603 option option 38 2 r46, r83 res, 0603 option option dc2493af demo manual dc2493a
6 item qty reference part description manufacturer/part number hardware: for demo board only 39 9 e1, e2, e4, e5, e6, e7, e8, e9, e10 turret miil-max 2501-2-00-80-00-00-07-0 40 5 lug ring, #10 keystone 8205 41 10 nut, brass 10-32 any #10-32 42 1 jp1 header, 3pin, dbl row 2mm sullins, nrpn032paen-rc 43 1 jp2 header, 2mm, 3pin sullins, nrpn031paen-rc 44 5 washer, #10 tin plated brass any #10 ext bz tn 45 4 j1, j2, j3, j4 stud, testpin pem kfh-032-10 46 2 xjp1, xjp2 shunt, 2mm p arts list dc2493af demo manual dc2493a
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. s chematic diagram a a b b c c d d e e 4 4 3 3 2 2 1 1 burst pulse skip/ext sync fcc ser2918h-682 ser2918h-682 pcb ? no. sns1+ sns2+ sw1 s1- run1 bg2 s2- tg2 ith1 s1- s1+ s2+ s2- s2+ sw2 bg1 s1+ tg1 vfb1 ith1 tr/ss1 run1 tr/ss1 vfb1 vin vin vout intvcc vout intvcc vin intvcc vout intvcc vout intvcc vin intvcc intvcc vout vout 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 2 monday, may 02, 2016 11 high power 60v, 2-phase synchronous ` \ ^ i n/a ltc3892euh-2 demo circuit 2493a step-down supply 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 2 monday, may 02, 2016 11 high power 60v, 2-phase synchronous ` \ ^ i n/a ltc3892euh-2 demo circuit 2493a step-down supply 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 2 monday, may 02, 2016 11 high power 60v, 2-phase synchronous ` \ ^ i n/a ltc3892euh-2 demo circuit 2493a step-down supply revision history description date approved rev ia ^a prod 2 03/21/16 revision history description date approved rev ia ^a prod 2 03/21/16 revision history description date approved rev ia ^a prod 2 03/21/16 c27 1uf c3 0.1uf r1 2.2 1% c1 2.2uf 100v e8 gnd q2 opt 3 1 2 4 5 q8 opt 3 1 2 4 5 c33 0.1uf r30 90.9k 1% c5 0.1uf r22 opt + c47 opt c23 10uf c13 220pf q3 bsc117n08ns5 3 1 2 4 5 r_prg 31.6k 1% q1 bsc117n08ns5 3 1 2 4 5 c21 10uf c18 1uf c51 2.2uf 0805 r21 opt r19 100 e2 gnd c29 opt r83 opt jp1 mode 1 2 3 4 5 6 r10 0 c9 6.8nf l2 6.8uh r25 opt c7 10pf + c2 56uf 63v r33 opt r5 opt c35 opt u1 ltc3892euh-2 tk/ss1 27 ith1 29 vfb1 30 vfb2 11 ith2 12 tk/ss2 15 sense2- 9 sense2+ 10 run2 7 extvcc 21 drvuv 13 sw2 17 tg2 16 boost2 18 drvcc 20 bg2 19 intvcc 5 vin 22 bg1 23 boost1 24 tg1 26 sw1 25 pllin/mode 2 freq 1 run1 6 sense1+ 31 sense1- 32 gnd 33 drvset 14 ilim 8 vprg1 28 pgood1 3 pgood2 4 r8 100k c41 opt c24 10uf r17 0 + c25 150uf r12 0 rs4 opt r18 0 c22 10uf + c20 150uf j4 gnd c11 0.1uf r23 opt r11 35.7k 1% r36 0 r14 9.76k 1% c48 opt r27 0 c12 220pf l1 6.8uh r16 0 j2 gnd j3 vout 12v / 30a rs2 2m c42 opt r13 opt + c49 opt r7 0 r24 opt e4 extvcc c6 47pf r34 0 r46 opt r4 opt c15 2.2uf r28 0 c32 opt j1 vin 16v up to 55v c50 opt q6 bsc026n08ns5 3 1 2 4 5 r20 100 c34 opt rs3 opt c43 opt r26 opt r2 opt r31 100k q7 bsc026n08ns5 3 1 2 4 5 c31 0.22uf q5 opt 3 1 2 4 5 + c40 opt 63v c4 2.2uf 25v 0805 c8 47pf c16 2.2uf 100v e9 vout jp2 on off run 1 3 2 e1 sync c44 opt c14 2.2uf e10 gnd r32 100k c30 0.22uf c28 opt rs1 2m c17 2.2uf 100v r9 499k 1% r29 opt e5 pgood c45 opt e7 vin r3 0 q4 opt 3 1 2 4 5 c46 opt dc2493af demo manual dc2493a
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 0516 ? 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 dc2493af demo manual dc2493a
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