1 description LT3753 active clamp forward converter with synchronous rectification demonstration circuits 2324a-a, 2324a -b, and 2324a-c are active clamp forward converters with synchronous rectification featuring the lt ? 3753. these circuits were designed to demonstrate the high level of performance, efficiency and small solution size attainable using this part. they operate at 240khz. the dc2324a-a produces a 24v/5a output from an input voltage range of 36v to 72v. the dc2324a-b produces a 24v/5a output from an input voltage range of 18v to 36v. the dc2324a-c produces a 24v/4a output from an input voltage range of 9v to 18v , making it suitable for telecom, industrial and other isolated power supply applications. they all have an eighth-brick footprint area. synchronous rectification helps to attain efficiency exceeding 94% (exceeding 95% for the dc2324a-a and dc2324a-b). l , lt, ltc, ltm, linear technology 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 d c 2324 a - a p erformance s ummary d c 2324 a -b the dc2324 a circuits feature soft-start which prevents output voltage overshoot during startup or when recover - ing from an overload condition. the dc2324 a also has a precise overcurrent protection cir cuit that allows for continuous operation and low power dissipation during short cir cuit conditions which ensures high reliability. please refer to the LT3753 data sheet for design details and applications information. design files for this circuit board are available at http://www.linear.com/demo/dc2324a specifications are at t a = 25c specifications are at t a = 25c symbol parameter conditions min typ max units v in input supply range 36 72 v v out output voltage 21.6 24 26.4 v i out maximum output current, continuous 5 a f sw switching (clock) frequency 240 khz v out p-p output ripple v in = 48v, i out = 5a (20mhz bw) 40 mv pCp p out /p in efficiency (see figure 2) v in = 48v, i out = 5a 95.6 % symbol parameter conditions min typ max units v in input supply range 18 36 v v out output voltage 21.6 24 26.4 v i out maximum output current, continuous 5 a f sw switching (clock) frequency 240 khz v out p-p output ripple v in = 24v, i out = 5a (20mhz bw) 30 mv pCp p out /p in efficiency (see figure 3) v in = 24v, i out = 5a 95.7 % dc2324aabcfa demo manual dc2324a-a, dc2324a-b, dc2324a-c
2 quick s tart p roce d ure demonstration circuit 2324a is easy to set up to evalu - ate the performance of the LT3753. refer to figure 1 for proper measurement equipment setup and follow the procedure below: 1. set an input power supply that is capable of cover - ing the input voltage range of the dc2324a ( see the performance summar y table ) to one of these voltages: 48v for the dc2324a-a, 24v for the dc2324a-b, 12v for the dc2324a-c. then turn off the supply. 2. with power off, connect the supply to the input ter - minals +v in and Cv in . if effciency measurements are desired, an ammeter with proper rating can be put in series with the input supply in order to measure the dc2324as input current. 3. turn on the power at the input. note: ma ke sure that the input voltage does not exceed 100v. 4. check for the proper output voltage of 24 v. turn off the power at the input. 5. once the proper output voltage is established, connect a variable load capable of sinking 5 a at 24 v to the output terminals +v out and Cv out . set the current for 0a. a. if effciency measurements are desired, an ammeter that is capable of handling 5a dc can be put in series with the output load in order to measure the dc2324 as output current. b. a voltmeter can be placed across the output terminals in order to get an accurate output voltage measure - ment. 6. turn on the power at the input. note: if there is no output, temporarily disconnect the load to make sure that the load is not set too high. 7. once the proper output voltage is again established, adjust the load within the operating range and observe the output voltage regulation, ripple voltage, effciency and other desired parameters. note: when measuring the input or output voltage ripples, 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 and Cv in , or +v out and Cv out terminals. p erformance s ummary d c 2324 a - c specifications are at t a = 25c symbol parameter conditions min typ max units v in input supply range 9 18 v v out output voltage 21.6 24 26.4 v i out maximum output current, continuous 4 a f sw switching (clock) frequency 240 khz v out p-p output ripple v in = 12v, i out = 4a (20mhz bw) 30 mv pCp p out /p in efficiency (see figure 4) v in = 12v, i out = 4a 94.8 % dc2324aabcfa demo manual dc2324a-a, dc2324a-b, dc2324a-c
3 quick s tart p roce d ure figure 2. dc2324a-a efficiency figure 3. dc2324a-b efficiency figure 4. dc2324a-c efficiency figure 1. proper measurement equipment setup dc2324 f01 load v in i in + ? + ? + ? v in + ? v out i out + ? + ? load current (a) 0 efficiency (%) 100 95 85 90 80 75 dc2324 f02 5 2 4 1 3 v in = 36v v in = 48v v in = 72v load current (a) 0 efficiency (%) 100 95 85 90 80 75 dc2324 f03 5 2 4 1 3 v in = 18v v in = 24v v in = 36v load current (a) 0 efficiency (%) 100 95 85 90 80 75 dc2324 f04 2 4 1 3 v in = 9v v in = 12v v in = 18v dc2324aabcfa demo manual dc2324a-a, dc2324a-b, dc2324a-c
4 quick s tart p roce d ure figure 5. dc2324a-a output ripple at 48v in and 5a out (20mhz bw) figure 6. dc2324a-b output ripple at 24v in and 5a out (20mhz bw) figure 7. dc2324a-c output ripple at 12v in and 4a out (20mhz bw) 2s/div 20mv/div dc2324 f05 2s/div 20mv/div dc2324 f06 2s/div 20mv/div dc2324 f07 dc2324aabcfa demo manual dc2324a-a, dc2324a-b, dc2324a-c
5 quick s tart p roce d ure figure 8. dc2324a-a thermal map, front side at 48v in and 5a out (t a = 25c) figure 9. dc2324a-a thermal map, back side at 48v in and 5a out (t a = 25c) figure 10. dc2324a-b thermal map, front side at 24v in and 5a out (t a = 25c) dc2324aabcfa demo manual dc2324a-a, dc2324a-b, dc2324a-c
6 quick s tart p roce d ure figure 11. dc2324a-b thermal map, back side at 24v in and 5a out (t a = 25c) figure 12. dc2324a-c thermal map, front side at 12v in and 4a out (t a = 25c) figure 13. dc2324a-c thermal map, back side at 12v in and 4a out (t a = 25c) dc2324aabcfa demo manual dc2324a-a, dc2324a-b, dc2324a-c
7 p arts list item qty reference part description manufacturer/part number required circuit components for dc2324a-a, dc2324a-b, and dc2324a-c 1 1 co1 cap., x7r, 10f, 50v, 10% 1210 murata, grm32er71h106ka12l 2 1 csys cap., alum., 270f, 35v, g size panasonic, eehza1v271p 3 1 cy1 cap., x7r, 2200pf, 250v, 10% 2220 murata, ga355qr7gf222kw01l 4 3 c1, c3, c5 cap., x7r, 0.1f, 50v, 10% 0603 murata, grm188r71h104ka93d 5 1 c2 cap., x7r, 4.7f, 25v, 10% 0805 murata, grm21br71e475ka73l 6 1 c4 cap., x7s, 1f, 100v, 10% 0805 murata, grj21bc72a105ke11l 7 1 c7 cap., x7r, 2.2nf, 250v, 10% 0805 murata, grm21ar72e222kw01d 8 1 c9 cap., c0g, 680pf, 50v, 5% 0603 wurth elektronik, 885012006062 9 1 d1 diode, cmmr1u-02 sod-123f central semi., cmmr1u-02 10 2 d2, d3 diode, bav21w, sod-123 micro commercial co., bav21w-tp 11 1 d4 diode, bat54a, sot23 diodes., bat54a-7-f 12 1 d5 diode, high-speed diode, sod-523 nxp/phillips semi., bas516 13 1 l1 inductor, 39h, champs, hrpqa2050-39 14 2 q3, q4 n-mosfet, power 56 fairchild, fdms86200dc 15 1 r1 res., chip, 31.6k, 0.1w, 1% 0603 vishay, crcw060331k6fkea 16 1 r2 res., chip, 100k, 0.1w, 1% 0603 vishay, crcw0603100kfkea 17 1 r6 res., chip, 61.9k, 0.1w, 1% 0603 vishay, crcw060361k9fkea 18 1 r9 res., chip, 200k, 0.125w, 1% 0805 vishay, crcw0805200kfkea 19 1 r14 res., chip, 15, 0.1w, 1% 0603 vishay, crcw060315r0fkea 20 1 r3 res., chip, 10k, 0.1w, 1% 0603 vishay, crcw060310k0fkea 21 2 r4, r10 res., chip, 10, 0.1w, 1% 0603 vishay, crcw060310r0fkea 22 1 r11 res., chip, 20k, 3/4w, 1% 2010 vishay, crcw201020k0fkef 23 2 r12, r13 res., chip, 100, 0.1w, 1% 0603 vishay, crcw0603100rfkea 24 1 u1 i.c., LT3753efe#trpbf, tssop-38(31) linear tech., LT3753efe#trpbf dc2324a-a required circuit components 25 4 cin1Ccin4 cap., x7s, 4.7f, 100v, 10% 1210 murata, grj32dc72a475ke11l 26 1 c6 cap., x7r, 47nf, 250v, 10% 1206 murata, grm31cr72e473kw03l 27 1 q1 n-mosfet power-56 fairchild, fdms86200dc 28 1 q2 p-mosfet power-33 vishay, si7117dn-t1-e3 29 1 rcs1 res., chip, 0.011, 1w, 1%, wide 1206 susumu, prl1632-r011-f-t5 30 1 r5 res., chip, 28k, 0.1w, 1% 0603 vishay, crcw060328k0fkea 31 1 r7 res., chip, 3.48k, 0.1w, 1% 0603 vishay, crcw06033k48fkea 32 1 r8 res., chip, 4.22k, 0.1w, 1% 0603 vishay, crcw06034k22 fkea 33 1 t1 transformer, champs, g45r2-0808-s01-80r dc2324a-b required circuit components 25 4 cin1-cin4 cap ., x7r, 10f, 50v, 10% 1210 murata, grm32er71h106ka12l 26 1 c6 cap., x7r, 150nf, 250v, 10% 1210 murata, grm32qr72e154kw01l 27 1 q1 n-mosfet power-56 fairchild, fdms86101dc 28 1 q2 p-mosfet sot23 vishay, si2337ds-t1-ge3 29 1 rcs1 res., chip, 0.005, 1w, 1%, 0815 susumu, rl3720wt-r005-f 30 1 r5 res., chip, 40.2k, 0.1w, 1% 0603 vishay, crcw060340k2fkea dc2324aabcfa demo manual dc2324a-a, dc2324a-b, dc2324a-c
8 p arts list item qty reference part description manufacturer/part number 31 1 r7 res., chip, 7.32k, 0.1w, 1% 0603 vishay, crcw06037k32fkea 32 1 r8 res., chip, 8.66k, 0.1w, 1% 0603 vishay, crcw06038k66fkea 33 1 t1 transformer, champs, g45r2-0408-s01-25r dc2324a-c required circuit components 25 4 cin1-cin4 cap., x7r, 22f, 25v, 10% 1210 murata, grm32er71e226ke15l 26 1 c6 cap., x7r, 330nf, 250v, 10% 1812 murata, grm43dr72e334kw01l 27 1 q1 n-mosfet pg-tdson infineon, bsc010n04lsatma1 28 1 q2 p-mosfet sc-70 vishay, sq1421eeh-t1-ge3 29 1 rcs1 res., chip, 0.003, 1w, 1%, 0815 susumu, rl3720wt-r003-f 30 1 r5 res., chip, 40.2k, 0.1w, 1% 0603 vishay, crcw060340k2fkea 31 1 r7 res., chip, 16.2k, 0.1w, 1% 0603 vishay, crcw060316k2fkea 32 1 r8 res., chip, 19.6k, 0.1w, 1% 0603 vishay, crcw060319k6fkea 33 1 t1 transformer, champs, g45r2-0208-s01-8r0 additional demo board circuit components for all versions 1 0 co2(opt) cap., 1210 2 0 c8(opt) cap., 100v, size 12x10 hardware: for demo board only (all versions) 1 2 e1, e2 testpoint, turret, 0.061" pbf mill-max, 2308-2-00-80-00-00-07-0 2 4 e3, e4, e5, e6 testpoint, turret, 0.094" pbf mill-max, 2501-2-00-80-00-00-07-0 3 4 j1-j4 banana jack keystone, 575-4 4 4 mh1-mh4 stand-off, nylon 9.5mm wurth elektronik, 702933000 dc2324aabcfa demo manual dc2324a-a, dc2324a-b, dc2324a-c
9 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 5 5 4 4 3 3 2 2 1 1 d d c c b b a a +vout * -vin * +vin note: unless otherwise specified: all resistors & capacitors are 0603 . all resistors are 1% resistors. all ceramic capacitors are x7r eval1: efe package (fe38 (31) ) board size: 2.30 by 1.45 -vout sync gnd 9v - 18v - a * 36v - 72v - c 18v - 36v versions - b cin1 - cin4 +vin for assembly 4.7uf / 100v,x7s 10uf / 50v 22uf / 25v rcs1 11m / wide 1206 5m / 0815 3m / 0815 q1 fdms86200dc fdms86101dc bsc010n04ls q2 si7117dn si2337ds sq1421eeh 24v / 4a 24v / 5a 24v / 5a +vout t1 g45r2-0808-s01-80r g45r2-0408-s01-25r g45r2-0208-s01-8r0 c6 47nf / 1206 150nf / 1210 330nf / 1812 r8 4.22k 8.66k 19.6k r5 28k 40.2k 40.2k 3.48k 7.32k r7 16.2k +vo1 intvcc sgnd csw csw fsw fsw q2 * cin1 * 1210 r5 * co2 1210 opt c4 1uf 100v 0805 x7s q3 fdms86200dc c1 0.1uf j4 e3 c3 0.1uf j1 10uf 50v co1 1210 c6 * 250v r1 31.6k r2 100k c9 680pf c0g r6 61.9k r7 * r3 10k cy1 2200pf 250v 2220 cin3 + c8 opt r14 15 r9 200k 0805 e4 r4 10 r13 100 rcs1 * e6 d3 bav21w-tp r10 10 d4 bat54a-7-f l1 39uh hrpqa2050-39 e1 q1 * cin2 c5 0.1uf u1 LT3753efe comp 5 fb 4 rt 3 sync 6 tblnk 14 ss1 7 tos 13 gnd 18 nc 2 ss2 17 out 24 aout 32 oc 22 isensen 20 isensep 21 vin 28 nc 34 test2 36 test1 1 tas 12 tao 11 ivsec 8 uvlo_vsec 9 ovlo 10 intvcc 26 sout 30 pgnd 19 pgnd 38 pgnd 39 nc 15 nc 16 nc 37 e2 r12 100 d1 cmmr1u-02 c2 4.7uf 25v 0805 d5 bas516 cin4 r11 20k 2010 j2 d2 bav21w-tp j3 e5 2.2nf 250v c7 0805 r8 * + csys 270uf 35v eehza1v271p q4 fdms86200dc t1 * 5 2 8 11 7 12 dc2324aabcfa demo manual dc2324a-a, dc2324a-b, dc2324a-c
10 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 0816 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 dc2324aabcfa demo manual dc2324a-a, dc2324a-b, dc2324a-c
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