LINEAR TECHNOLOGY LT1737 1737fa User Guide
Summary
The LT1737 is an advanced isolated flyback switching regulator controller engineered for reliable power conversion in critical applications such as medical instruments and complex instrumentation power supplies. This manual provides comprehensive details on utilizing this robust IC to efficiently convert input voltages from 4.5V to 20V into regulated, isolated DC outputs. Designed with key safety features, including Undervoltage Lockout (UVLO) and soft-start capability, it ensures superior performance and stability across both continuous and discontinuous load modes, making it essential for sophisticated power management designs.
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 1737fa User Guide
Manual Details
| Brand | Linear |
|---|---|
| Pages | 28 |
| File Size | 372.72 KB |
| Published | June 02, 2026 |
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Frequently Asked Questions
Does the LT1737 require an optoisolator for feedback sensing?
No, it can sense output voltage directly from the primary side or use a third transformer winding or direct DC feedback.
What is the operational supply voltage range for this controller?
The LT1737 operates within a supply voltage range of 4.5V to 20V.
How does the device maintain stable regulation under variable loads?
It uses current mode switching techniques, allowing it to maintain good regulation even into discontinuous mode.
What protection features are available for the system input power?
There is an optional Undervoltage Lockout (UVLO) feature that stops operation if the application input voltage drops too low.