28
LT1737
1737fa
TYPICAL APPLICATIO S
U
V
C
R1
0.025Ω
M1
IRLZ34S
L1
15µH
R2
2.7Ω
5%
R10
51Ω
5%
1737 F18
R7
100k
5%
R6
24k
5%
C6
47pF
50V
NPO
6
8
7
3
910 15
16
2
1
2
8
3
14 13 12 4 5 11 1
C5
4.7nF
50V
X7R
R5
33k
5%
R11
22k
5%
R12
24k
5%
C1: SANYO OS-CON (20SV150M)
C2A-B: TOKIN Y5V (IE226ZY5U-C505)
C3: SANYO POSCAP (16TPC33M)
D1: MOTOROLA 40V, 6A SCHOTTKY DIODE
R13
20k
5%
R4
3.01k
1%
R3
26.1k
1%
R8
160k
5%
R9
33k
5%
C4
1µF
25V
Z5U
C1
150µF
20V
V
IN
L2
15µH
C10
470pF
50V
X7R
C9
47pF
50V
NPO
C7
47pF
50V
NPO
OUT
U2
LT1121
ADJ
INP
GND
D1
MBRD640CT
+
C3
33µF
16V
×4
C2A
22µF
25V
C2B
22µF
25V
+
R14
750Ω
5%
V
OUT
= 12V
C8
0.1µF
25V
Z5U
L1, L2: COILTRONICS UP4B-150 INDUCTOR
M1: INT’L RECTIFIER IRLZ34S 60V, 0.05Ω LOGIC LEVEL N-CH MOSFET
R1: IRC 4 × 0.1Ω, 1W (LR2512)
PGND
I
SENSE
GATEFB
V
CC
UVLO3V
OUT
SGNDR
CMPC
R
OCMP
MINENAB
LT1737
ENDLYSFSTOSCAP t
ON
Figure 18. 8V-16V to 12V Nonisolated Converter
0.01
60
EFFICIENCY (%)
70
80
90
0.1 1 10
1737 F19
50
40
30
20
I
LOAD
(A)
V
IN
= 8V
V
IN
= 16V
V
IN
= 12V
Figure 19. Efficiency vs I
LOAD
PART NUMBER DESCRIPTION COMMENTS
LT1424-5 Isolated Flyback Switching Regulator V
IN
= 3V to 20V, I
Q
= 7mA
LT1424-9 Isolated Flyback Switching Regulator V
IN
= 3V to 20V, I
Q
= 7mA
LT1425 Isolated Flyback Switching Regulator General Purpose with External Application Resistor
LT1533 Ultralow Noise 1A Switching Regulator V
IN
= 2.7V to 23V, Reduced EMI and Switching Harmonics
LT1725 General Purpose Isolated Flyback Controller Suitable for Telecom or Offline Input Voltage
LT1738 Ultra Low Noise DC/DC Controller Reduced EMI and Switching Harmonics
RELATED PARTS
© LINEAR TECHNOLOGY CORPORATION 2000
LT/LT 0605 REV A • PRINTED IN THE USA
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
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