LINEAR TECHNOLOGY LT1737 User Guide
Summary
The LT1737 is a high-power isolated flyback controller IC perfect for designing robust DC/DC power supplies. This monolithic regulator drives external MOSFETs and supports topologies from 4.5V to 20V, ensuring stable operation even in discontinuous mode. The device features multiple sensing options—including primary winding feedback and direct DC links—making it ideal for demanding applications like medical instruments and industrial power supplies. The accompanying manual provides comprehensive data, including detailed electrical specifications, physical package details, and proven typical application circuits to guide your design process from concept to finished product.
Page 1 Text Content
LT1737 High Power
Isolated Flyback Controller
FEATURES DESCRIPTIO Drives External Power MOSFET The LT®1737 is a monolithic switching regulator control- Supply Voltage Range: 4.5V to 20V ler specifically designed for the isolated flyback topology. Flyback Voltage Limited Only by It drives the gate of an external MOSFET and is generally External Components powered from a DC supply voltage. Output voltage feed-
Senses Output Voltage Directly from Primary Side back information may be supplied by a variety of methods Winding—No Optoisolator Required including a third transformer winding, the primary wind- Switching Frequency from 50k Hz to 250k Hz ing or even direct DC feedback (see Applications Informa- with External Capacitor tion). Its gate drive capability, coupled with a suitable Moderate Accuracy Regulation Without User Trims external MOSFET and other power path components, can Regulation Maintained Well into Discontinuous Mode deliver load power up to tens of Watts.
External ISENSE Resistor
The LT1737 has a number of features not found on other
Optional Load Compensation
isolated flyback controller ICs. By utilizing current mode
Optional Undervoltage Lockout
switching techniques, it provides excellent AC and DC line
Shutdown Feature Reduces IQ to 50µA Typ
regulation. Its unique control circuitry can maintain regu-
Available in 16-Pin GN and SO Packages
lation well into discontinuous mode in most applications. Optional load compensation circuitry allows for improved APPLICATIO S load regulation. An optional undervoltage lockout pin halts operation when the application input voltage is too
Isolated Flyback Switching Regulators
low. An optional external capacitor implements a soft-
Medical Instruments
start function.
Instrumentation Power Supplies
, LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
12V-18V to Isolated 15V Converter
R2 VIN 35.7k 1%
22µF COILTRONICS
D2 MBRS1100
CTX150-4
BAS16Q1
VOUT = 15V
IOUT = 300m A
VCCUVLO
FB GATE
IRFL014
LT1737
VC ISENSE
t ON ENDLYOSCAP RCMPCROCMPMINENAB SGND PGND R1
1% NOTE: SEE APPLICATIONS
1n F 47p F 75k 150k 100k 4.7k 0.1µF INFORMATION FOR ADDITIONAL
COMPONENT SPECIFICATIONS
1737 TA01
1737fa
Page Summary Contents For LINEAR TECHNOLOGY LT1737 User Guide
Manual Details
| Brand | Linear |
|---|---|
| Pages | 28 |
| File Size | 373.58 KB |
| Published | June 16, 2026 |
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Frequently Asked Questions
What is the acceptable supply voltage range for this controller?
The LT1737 supports a Supply Voltage Range from 4.5V to 20V.
Does the isolated flyback topology require an optoisolator or third winding?
No Optoisolator Required; it uses information supplied by the primary winding.
Under what load conditions can this controller maintain regulation?
It can maintain Regulation well into Discontinuous Mode in most applications.
What protective features are available for startup and input voltage monitoring?
It includes optional Undervoltage Lockout (UVLO) and a Shutdown feature to reduce current to 50µA Typ.