5 4 3 2 1 VIN L1 3.3uH P1 +VIN +VIN 36V-72V KEYSTONE 1425-2 5678 DO1608C-332 COILCRAF T R1 10 Q1 Si7456DP 2 4 123 1 T1 SCHOTT 39402 C3 0.82uF 100V 1812 C2 0.82uF 100V 1812 1 D2 MURS120 D1 MURS120 2 4 5678 R2 10 2 123 1 3 3 2 2 A 5 R31 C19 0.022uF 1K 14 15 SYNC 6 8 14 OPTODRV VAUX 2 C33 0.1uF 50V 0805 R46 1K PWRGGD C22 4700pF 5 C30 4700pF 5 R34 3.01K 1% VFB 8 OVPIN 9 MARGIN 7 2 R20 3.01K -SENSE P5 -SENSE 1% KEYSTONE 1425-2 R21 R22 3.01K 100 1% 1/4W 1206 ICOMP 13 B R33 2.43K 1% TRIM R38 1K R47 1.78K 1% -VOUT R48 1.24K 1% CONTRACT NO. APPROVALS NOTES: UNLESS OTHERWISE SPECIFIED 1. TO DISABLE OPTIONAL FAST START: REMOVE C12, D8, D9, R8, R9, R11, R15, Q9, Q11; ADD R25 = 20K. 2. TO DISABLE OPTIONAL DIFFERENTIAL SENSE: REMOVE R12, R14, R19-22, U1; ADD R28 = 0 OHM. DRAWN: APPROVED: ENGINEER: BOB S. DESIGNER: TECHNOLOGY KIM T. CHECKED: 3. ALL RES. ARE IN OHMS, 0603. ALL CAP. ARE 0603. ALL DIODES ARE MMBD914BLT1. ALL NPNs ARE MMBT3904LT1. ALL PNPs ARE MMBT3906LT1. 4 3 2 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 LTC Confide ntial-For Customer Use Only TITLE: ISOLATED SYNCHRONOUS FORWARD CONVERTER SIZE A DATE: 5 P6 TRIM KEYSTONE 1425-2 VOUT C23 0.22uF 0805 10 7 U2 LTC1698EGN R35 1K +SENSE KEYSTONE 1425-2 R14 3.01K 1% R28 OPT 6 16 11 2 CG FG 0805 GND VC 10 SS SGND 4 8 7 R37 3K ISO1 MOC207 43 1 5VREF R41 C26 10 3300pF R40 10K C29 0.01uF VFB 9 P7 OPTIONAL DIFFERENTIAL SENSE VOUT VCOMP PGND 12 3 1 VDD 1 R32 470 5 +SENSE 2 4 C21 0.1uF 50V ISNS 8 4 3 R49 OPT 3 1 12 SG 11 50V 0805 3 - D11 BAT54 OPT C16 1000pF -VIN SYNC 15 16 17 THERM 3 SENSE BG NC NC 19 TG 18 FSET R39 52.3K R42 1% 2.43K C32 1% C31 82pF 1uF 25V 1206 D14 BAT54 PULSE ENG. T2 PA01844 1 C17 220pF 1 R27 1K R23 1K 4 R45 1.24K 1% RT1 100K 1206 D12 BAT54 + 1% 9V PGND C18 3300pF R19 3.01K ISNSGND D10 MMBZ5240B 10V Q12 FZT690B 3 C25 C28 100uF 1000pF 20V 7343 + U1 LT1783CS5 1 R18 1001 1/4W 1206 C15 4.7uF 3 R17 10K R16 2K 1/4W 1206 3 C13 0.22uF 50V 1206 1 R43 10K U3 LT3781EG 6 SHDN BSTREF OVLO 5VREF 1 VCC 5 1 100V 1206 VBST 20 3 5VREF C24 0.1uF 50V 0805 1 3 16V 1210 C27 0.1uF 50V 0805 -VIN C20 0.1uF D13 BAS21 2 -VOUT STAFFALL C R12 100 1/4W 1206 9V -VIN R26 73.2K 1% 13 P4 VOUT 1 11 C14 330pF D15 MMBD9 14 ON/OFF KEYSTONE 1425-2 4 C5 C6 C7 330uF + 330uF + 330uF 6.3V 6.3V 6.3V KEMET KEMET KEME T 7343 7343 7343 + 321 D6 MBR0540 2 1 ON/OFF 3 4 321 C11 0 OHM 1206 D7 BAT54 VCC P2 + R10 4.7 1206 Q10 VIN VCC R4 10 1/4W 1206 C4 330uF 6.3V KEMET 7343 8765 1 3 ZVN3310F D8 Q11 MMBT3904 MMBZ5248B 18V R24 R25 270K OPT 1/4W 1206 1206 D 3 R11 62K 1/4W 1206 OPTIONAL FAST START B R3 10 1/4W 1206 Q6 Q7 Si7892DP Si7892DP 8765 1 2 C12 4.7uF 16V 1210 P8 3.3V@15A +VOUT STAFFALL -VOUT D4 BAS21 3 3 1 C9 1000pF 100V 1206 -VOUT D5 MBR0540 OPT 5VREF D9 R15 MMBD9 14 47K 1 3 +VOUT 1206 250V 2220 D3 BAS21 L2 1.0mH VIN 1 321 R6 C10 2200pF 3.3 3 VCC R9 100 1/4W 1206 VCC 4 321 1 4 2 C Q9 FQT7N10LTF -VIN C8 1000pF 100V 1206 8765 4 R5 0.030 2010 R8 100 1/4W 1206 Q4 Q5 Si7892DP Si7892DP 8765 Q3 Si7456DP 4 VOUT 6 3 Q8 MMBT3 906 P3 -VIN -VIN KEYSTONE 1425-2 L3 1.5uH 5 2 C1 0.82uF 100V 1812 2 D 1 1 3 Q2 MMBT3 906 DWG NO. DC479A-1 REV A LT3781EG/LTC1698EGN/LT1783CS5 Tuesday, September 24, 2002 1 SHEET 1 OF 1 A