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dc1739bcf

DEMO MANUAL DC1739B-C

DESCRIPTION

LTC3765/LTC3766 

120W Isolated Forward Converter 

with Synchronous Rectification 

Demonstration circuit 1739B-C is a 120W isolated forward 

converter  with  synchronous  rectification  featuring  the 

LTC

®

3765/LTC3766

 chip set.

This circuit was designed to demonstrate the high level of 

performance, efficiency, and small solution size attainable 

using this chip set in an active-clamp-reset forward con-

verter power supply. It operates at 240kHz and produces 

a regulated 12V, 10A output from an input voltage range 

of 9V to 36V: suitable for telecom, industrial, and other 

applications. It has an eighth-brick footprint area. Synchro-

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.

nous rectification helps to attain efficiency exceeding 94%. 

Secondary-side control eliminates complex opto-coupler 

feedback, providing fast transient response with minimum 

output capacitance. For other output requirements, see the 

LTC3766 data sheet or contact the LTC factory.

Design  files  for  this  circuit  board  are  available  at  

http://www.linear.com/demo

PERFORMANCE SUMMARY

Specifications are at T

A

 = 25°C

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

V

IN

Input Supply Range

9

36

V

V

OUT

Output Voltage 

12.0

V

I

OUT

Output Current Range, Continuous

200LFM

0

10

A

f

SW

Switching (Clock) Frequency

240

kHz

V

OUT(P-P)

Output Ripple

V

IN

 = 24V, I

OUT

 = 10A (20MHz BW)

40

mV

P–P

I

REG

Output Regulation

Line and Load (9V

IN

 to 36V

IN

, 0A

OUT

 to 10A

OUT

)

±0.27

%

P

OUT

/P

IN

Efficiency (See Figure 3)

V

IN

 = 24V, I

OUT

 = 10A

92.7

%

Isolation

Basic

1500

VDC

Approximate Size

Component Area 

×

 Top Component Height

2.3 

×

 0.9 

×

 0.47

Inches

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Summary of Contents for DC1739B-C

Page 1: ...on All other trademarks are the property of their respective owners nousrectificationhelpstoattainefficiencyexceeding94 Secondary side control eliminates complex opto coupler feedback providingfasttra...

Page 2: ...electrolytic capacitor has been added at the input terminals to provide suitable dampingandripplecurrentcapability Thevaluesselected haveafilterresonantfrequencythatisbelowtheconverter switching frequ...

Page 3: ...n on the power at the input Note Ifthereisnooutput temporarilydisconnecttheload to make sure that the load is not set too high 8 Once the proper output voltage is again established adjust the load wit...

Page 4: ...E Figure 3 Output Ripple at 24VIN and 10AOUT 50mV 5A 2 s Div 20MHz Figure 4 Transient Response Waveform at 24VIN and 5A 7 5A 5AOUT 5A 100mV 100 s Div Downloaded from Arrow com Downloaded from Arrow co...

Page 5: ...ure 5 Thermal Map Front Side at 24VIN and 10AOUT TA 25 C 200LFM Figure 6 Thermal Map Back Side at 24VIN and 10AOUT TA 25 C 200LFM Downloaded from Arrow com Downloaded from Arrow com Downloaded from Ar...

Page 6: ...pF 25V 5 0603 AVX 06033A102JAT2A 22 1 C36 CAP X7R 1500pF 50V 10 0402 AVX 04025C152KAT2A 23 1 C39 CAP X7R 1 0uF 50V 10 0805 MURATA GRM21BR71H105KA12 24 1 D1 DIODE ULTRA FAST 1A 200V SMP VISHAY ES1PD M3...

Page 7: ...RANSFORMER 3T 6T CHAMPS G45R2 0603 xx 50 1 T3 TRANSFORMER 1 25T 1T COILCRAFT CT8281 BL 51 1 U1 I C LTC3765EMSE MSOP 16PIN LINEAR TECH LTC3765EMSE 52 1 U2 I C LTC3766EGN28 SSOP GN28 LINEAR TECH LTC3766...

Page 8: ...B C SCHEMATIC DIAGRAM Downloaded from Arrow com Downloaded from Arrow com Downloaded from Arrow com Downloaded from Arrow com Downloaded from Arrow com Downloaded from Arrow com Downloaded from Arrow...

Page 9: ...ionmakesnorepresenta tion that the interconnection of its circuits as described herein will not infringe on existing patent rights SCHEMATIC DIAGRAM COMPLETE PCB Downloaded from Arrow com Downloaded f...

Page 10: ...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 r...

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