5 4 P1 +VIN +VIN 3 R1 10 Q1 Si7456DP 2 4 C3 0.82uF 100V 1812 3 5 D2 MURS120 D1 MURS120 5678 R2 10 2 3 3 VIN Q4 Si7892DP D3 BAS21 R6 3.3 250V 2220 1206 8765 C9 1000pF 100V 1206 R4 10 1/4W 1206 R3 10 1/4W 1206 4 321 Q6 Si7892DP 8765 Q7 Si7892DP C4 8765 4 321 + 330uF 6.3V KEMET 7343 4 1 T3 P0926 VS 1 VOUT C 1 2 5 3 D7 BAT54 3 1 1 D5 BAS21 7V -VOUT R45 1.24K 1% 3 1% C31 1uF 25V 1206 3 R32 470 5 1 8 PGND 14 VDD 1 ISNS 12 1 SG 12 SENSE 11 C29 0.01uF 0805 15 SYNC R37 3K R41 10 5VREF ISO1 MOC207 43 1 7 5 C30 4700pF 8 14 VAUX C33 0.1uF 50V 0805 R31 1K R34 1.24K 1% B R33 1.47K 1% VFB 8 TRIM MARGIN 7 R38 1K ICOMP 13 C23 0.22uF VOUT -VOUT R48 1.24K 1% APPROVALS TECHNOLOGY DRAWN: CHECKED: 3. ALL RES. ARE IN OHMS, 0603. ALL CAP. ARE 0603. ALL DIODES ARE MMBD914BLT1. ALL NPNs ARE MMBT3904LT1. ALL PNPs ARE MMBT3906LT1. APPROVED: ENGINEER: DESIGNER: 3 2 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 LTC Confidential-For Customer Use Only TITLE: ISOLATED SYNCHRONOUS FORWARD CONVERTER SIZE A DATE: 4 TRIM 0805 R47 1.24K 1% NOTES: UNLESS OTHERWISE SPECIFIED 5 R22 100 1/4W 1206 OPTIONAL DIFFERENTIAL SENSE CONTRACT NO. 2. TO DISABLE OPTIONAL DIFFERENTIAL SENSE: REMOVE R12, R14, R19-22, U1; ADD R28 = 0 OHM. -SENSE R28 OPT A 1. TO DISABLE OPTIONAL FAST START: REMOVE C12, D8, D9, R8, R9, R11, R15, Q9, Q11; ADD R25 = 20K. P5 -SENSE 1% P6 2 R46 1K R20 3.01K OVPIN 9 5 OPTODRV C22 4700pF 6 C26 3300pF U2 LTC1698EGN R35 1K GND VFB 9 PGND 10 VC SS SGND 4 8 7 SYNC THERM NC 16 BG 15 50V 0805 C19 0.022uF -VIN 3 NC 17 19 C32 82pF R42 2.43K 1% D14 BAT54 4 3 VOUT C21 0.1uF 50V 10 PWRGGD C28 1000pF -VIN R40 10K R39 52.3K PULSE ENG. T2 PA0184 1 4 C17 220pF 3 - R21 3.01K 1% C16 1000pF 4 C25 100uF 20V 7343 + RT1 100K 1206 D12 BAT54 1 R27 1K R49 OPT R23 1K 3 C24 0.1uF 50V 0805 C18 3300pF TG BSTREF 18 5VREF R43 10K U3 LT3781EG 6 5 1 SHDN 5VREF 2 OVLO FSET 13 VCC VBST 20 100V 1206 D15 MMBD914 ON/OFF 3 1 C27 0.1uF 50V 0805 C20 0.1uF D13 BAS21 1 3 + D11 BAT54 OPT CG 2 VCOMP 6 VCC C11 0.1uF 50V 0805 +SENSE R14 3.01K 1% 1% ISNSGND 11 FG 16 C15 4.7uF 16V R26 73.2K 1% R19 3.01K 3 -VIN VIN VCC U1 LT1783CS5 1 4 R17 10K P7 +SENSE 7V 5 D8 MMBZ5248B 18V OPTIONAL FAST START B R12 100 1/4W 1206 2 R25 OPT 1206 -VOUT -VOUT 2 Q10 3 ZVN3310F C14 330pF R24 270K 1/4W 1206 6.3V KEMET 7343 P4 1 1 C12 4.7uF 16V 1210 Q11 MMBT3904 C7 + 330uF 6.3V KEMET 7343 VOUT 3 3 R15 47K C6 + 330uF 6.3V KEMET 7343 -VOUT 3 D9 MMBD914 1 3 C5 + 330uF 321 2 5VREF ON/OFF C8 1000pF 100V 1206 6 VCC P2 Q5 Si7892DP 8765 C10 2200pF D4 BAS21 R11 62K 1/4W 1206 1 C L2 1.0mH D 3 1/4W 1206 8 1 4 2 Q9 FQT7N10LTF 1/4W 1206 2 2.5V@20A +VOUT PA0469 321 -VIN R9 100 2T 4 2010 R8 100 10T R5 0.030 VCC P8 +VOUT 123 -VIN VOUT 10 1 Q3 Si7456DP P3 L3 1.45uH 9T 4 1 Q8 MMBT3906 -VIN VS 6 2 C2 0.82uF 100V 1812 2 C1 0.82uF 100V 1812 T1 PA0463 123 1 1 1 Q2 MMBT3906 D 1 5678 DO1608C-332 COILCRAFT 36V-72V 2 VIN L1 3.3uH DWG NO. REV DC617A LT3781EG/LTC1698EGN/LT1783CS5 Thursday, October 17, 2002 SHEET 1 1 OF 1 A