Datasheet
20
LT1738
1738fa
PART NUMBER DESCRIPTION COMMENTS
LT1683 Ultralow Noise Push-Pull DC/DC Controller Dual Output (Push-Pull) Current Mode Architecture.
LT1425 Isolated Flyback Switching Regulator Excellent Regulation without Transformer “Third Winding”
LT1533 Ultralow Noise 1A Switching Regulator Push-Pull Design for Low Noise Isolated Supplies
LT1534 Ultralow Noise 2A Switching Regulator Ultralow Noise Regulator for Boost Topologies
LT1576 1.5A, 200kHz Step-Down Switching Regulator Constant Frequency, 1.21V Reference Voltage
LT176X Family Low Dropout, Low Noise Linear Regulator 150mA to 3A, SOT-23 to TO-220
LT1777 Low Noise Step-Down Switching Regulator Programmable dI/dt; Internally Limited dV/dt
LTC1922-1 Synchronous Phase Modulated Full-Bridge Controller Adaptive DirectSense
TM
Zero Voltage Switching, 50W to
Kilowatts, Synchronous Rectification
LT3439 Ultralow Noise Transformer Driver 1A Push-Pull DC/DC Transformer Driver
DirectSense is a trademark of Linear Technology Corporation.
LT/TP 1202 1K REV A • PRINTED IN USA
LINEAR TECHNOLOGY CORPORATION 2001
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear.com
TYPICAL APPLICATIO
U
RELATED PARTS
Ultralow Noise 30W Offline Power Supply
+
+
+
+
+
14
5
6
7
8
16
15
9
SHDN
V5
SYNC
C
T
R
T
R
VSL
R
CSL
F
B
2
1
4
18
20
12
CAP
GATE
CS
NC
PGND
V
C
13 11 3
U3
LT1738
V
IN
NC NFB
SS
GND
GCL
12V
IN755 A
165k
165k
51k
3.9k
3.9k
19.6k
1.8nF
2N2222
2N2222
510k
510k
100k
2W
56µF
35V
5pF
5pF
600V
470pF
COLL
RMIO
R
TOP
COMP
V
+
REF
65
3
2
8
4
7
V
OUT
5
4
6
ISO1
CNY17-3
U2
LT1431
1k
1k
0.1µF
38.3k
1%
10k
1%
MTP2N60E
NOTE: PIN 2 OF LT1738 MUST BE LAID OUT
AWAY FROM FAST SLEWING NODES
UNLESS OTHERWISE NOTED: ALL RESISTORS 1206, 5%
BR1: GENERAL INSTRUMENTS W06G
C2, C3, C4: SANYO MV-GX
100µF
400V
P6KE200A
MUR160
D4
BA521
10Ω
0.1µF
250VAC
“X2”
1M
1M
10nF
V
BIAS
X1
X3
90VAC
TO 264VAC
+V
OUT
12V
2.5A
–V
OUT
C4
330µF
25V
C3
330µF
25V
C2
330µF
25V
BR1
3
6
5
11
1
7
12
8
A1
A2
1738 TA02
KA
T1
1
2
3
G-F G-S
17 19 10
D1
0.068Ω
1/2W
1k
0.22µF
L1
DANGER: HIGH VOLTAGE
INPUT FILTER IS REQUIRED TO ATTENUATE SWITCHING FREQUENCY HARMONICS AND PASS FCC CLASS B (LT1738 DOES NOT ATTENUATE THESE LOW FREQUENCY HARMONICS)
MAIN ADVANTAGE WITH LT1738 IS IT MAKES SUPPRESSING THE HIGH FREQUENCY NOISE AND EMI EASY. THIS IS PARTICULARLY USEFUL FOR MEDICAL DEVICES BECAUSE
THE AC LINE TO EARTH GND CAPS ON THE INPUT FILTER CAN BE ELIMINATED; ALLOWING THE DEVICE TO PASS THE EARTH GND LEAKAGE CURRENT MEDICAL SPECIFICATIONS.
D1: MBR20200CT
L1: HM18-10001
T1: PREMIER MAGNETICS POL-15033
V
BIAS