LINEAR TECHNOLOGY LT1424-5 User Guide
Summary
The LT1424-5 is a powerful, monolithic switching regulator ideal for generating isolated 5V power supplies in demanding environments. This compact integrated circuit simplifies design by eliminating the need for external optoisolators or dedicated "third windings." The datasheet provides comprehensive coverage of electrical specifications, timing diagrams, and advanced application examples. It is perfect for industrial automation and instrumentation systems requiring stable, high-efficiency isolation that maintains regulation even when operating into discontinuous load modes.
Page 1 Text Content
LT1424-5 Isolated Flyback
Switching Regulator with 5V Output
FEATURES DESCRIPTIO No Transformer “Third Winding” or Optoisolator The LT®1424-5 is a monolithic high power switching Required regulator specifically designed for the isolated flyback Designed for Use with 1:1 Ratio Transformers topology. No “third winding” or optoisolator is required; Fixed, Application Specific 5V Output Voltage the integrated circuit senses the isolated output voltage Regulation Maintained Well into Discontinuous directly from the primary side flyback waveform. A high Mode (Light Load) current, high efficiency switch is included on the die along Load Compensation Provides Excellent with all oscillator, control and protection circuitry. Load Regulation
The LT1424-5 operates with input supply voltages from
Available in 8-Pin PDIP and SO Packages
3V to 20V and draws only 7m A quiescent current. It can
Operating Frequency: 285k Hz
deliver up to 400m A at 5V with no external power devices. By utilizing current mode switching techniques, it pro- vides excellent AC and DC line regulation.
APPLICATIO S
The LT1424-5 has a number of features not found on other
Isolated Communication Supplies switching regulator ICs. Its unique control circuitry can Industrial Automation maintain regulation well into discontinuous mode. Load Instrumentation Systems compensation circuitry allows for improved load regula-
tion. An externally activated shutdown mode reduces total
OU TP UT OL TA GE (V
supply current to 20µA typical for standby operation. , LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
5V Output Isolated Power Supply Load Regulation
ISOLATION BARRIER
MBRS130LT3 T1 5V
SHDN RCCOMP 100µF 1.8k
VC VIN 10V
MBR0540T4
LT1424-5
SYNC VSW
1000p F COM
1424-5 TA01
SGND PGND
C1, C2: AVX TPS D107M010R0080
INPUT T1: DALE LPE-4841-A307 4.75 COM
OUTPUT CURRENT (m A)
1424-5 TA02
sn14245 14245fs
Page Summary Contents For LINEAR TECHNOLOGY LT1424-5 User Guide
Manual Details
| Brand | Linear |
|---|---|
| Pages | 16 |
| File Size | 190.28 KB |
| Published | June 16, 2026 |
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Frequently Asked Questions
Does this regulator require a third winding or optoisolator for isolation?
No, the LT1424-5 is a monolithic high power switching regulator designed to provide required isolation without needing extra windings or optoisolators.
What is the operating input voltage range for the unit?
It can operate with input supply voltages ranging from 3V up to 20V.
Does the LT1424-5 maintain stable regulation under varying load conditions?
Yes, it provides excellent performance by maintaining regulation well into discontinuous conduction mode (DCM) and handling high load changes.
How much current does the device consume in standby or shutdown mode?
The typical quiescent current is 7mA, which can be reduced to only 15µA when placed in shutdown mode.