16
LT1680
–48V to 5V 30W Forward Converter
220µF
35V
5V
REF
C
T
I
AVG
SS
SYNC
LT1680
SENSE
+
RUN/SHDN
7
115
IRF640
MBR0520LT1
MBR2045CT
MBR2045CT
13109
16
11
14
1µF
0.1µF
300pF
1.5nF
T1
L1
20µH
1nF
0.1µF
0.1µF
L1: PHILIPS EFD20-3F3-E63-S
(CORE SET, AI = 63nH/T
2
)
OUTPUT 18T BIFILAR 22AWG
BIAS 54T BIFILAR 32AWG
T1: COILTRONICS VP5-1200, 1:1:1:1:1:1
(SIX WINDINGS EACH 77µH)
*SANYO CV-GX
**SANYO OS-CON
ALL RESISTORS 1.4W, 1% UNLESS
INDICATED OTHERWISE
0.22µF
2.2nF
16k
20k
78.7k
20k
1M
•
BAV21
L1
7.5k
10Ω
24k
INPUT
COM
–48V
INPUT
24k
24k
4.75k
1k
1680 TA03
2N7000
2N3904
23 45 6128
12V
IN
SENSE
–
GATE
V
C
V
FB
SGND PGND
SL/ADJ
V
REF
+
•••
•••
1.5nF
Q7
2N5401
330µF**
6.3V
5V
6A
OUT
OUTPUT
COM
0.033µF
33Ω
4.22k
1.2k
33Ω
0.015Ω
1W
50Ω
1W
1µF
63V
1k
+
220µF*
35V
+
220µF*
35V
+
220µF*
35V
+
220µF*
35V
+
PART NUMBER DESCRIPTION COMMENTS
LT1268 7.5A, 150kHz Switching Regulator Integrated Switch Can Be Used in Isolated Flyback Mode
LT1270A 10A, 60kHz Switching Regulator Integrated Switch Can Be Used in Isolated Flyback Mode
LT1339 High Power Synchronous DC/DC Controller Operation to 60V, No Shoot-Through N-Channel Output Drivers
LT1370 500kHz, 6A Boost Switching Regulator Integrated Switch, Regulates Positive or Negative Outputs
LT1371 500kHz, 3A Boost Switching Regulator Integrated Switch, Regulates Positive or Negative Outputs
LT1619 Low Voltage Current Mode DWM Controller 8-lead MSOP, 1.9V ≤ V
IN
≤ 18V
LTC1700 No R
SENSE
TM
Synchronous Current Mode Step-Up 95% Efficient, 0.9V ≤ V
IN
≤ 5V, 550kHz
DC/DC Controller
LT1738 Ultralow Noise DC/DC Boost Controller Greatly Reduced Conducted and Radiated EMI, N-Channel MOSFET Driver,
20kHz to 250kHz Oscillator Frequency
LTC3401/LTC3402 1A/2A 3MHz Micropower Synchronous Boost Converter 10-Lead MSOP, 0.5V ≤ V
IN
≤ 5V
No R
SENSE
is a trademark of Linear Technology Corporation.
1680af LT/TP 0301 REV A 2K • PRINTED IN USA
LINEAR TECHNOLOGY CORPORATION 1997
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
●
(408) 432-1900
FAX: (408) 434-0507
●
TELEX: 499-3977
●
www.linear-tech.com
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