with 5V Output
s No Transformer “Third Winding” or Optoisolator
s Designed for Use with 1:1 Ratio Transformers
s Fixed, Application Specific 5V Output Voltage
s Regulation Maintained Well into Discontinuous
Mode (Light Load)
s Load Compensation Provides Excellent
s Available in 8-Pin PDIP and SO Packages
s Operating Frequency: 285kHz
s Isolated Communication Supplies
s Industrial Automation
s Instrumentation Systems
The LT®1424-5 is a monolithic high power switching
regulator specifically designed for the isolated flyback
topology. No “third winding” or optoisolator is required;
the integrated circuit senses the isolated output voltage
directly from the primary side flyback waveform. A high
current, high efficiency switch is included on the die along
with all oscillator, control and protection circuitry.
The LT1424-5 operates with input supply voltages from
3V to 20V and draws only 7mA quiescent current. It can
deliver up to 400mA at 5V with no external power devices.
By utilizing current mode switching techniques, it pro-
vides excellent AC and DC line regulation.
The LT1424-5 has a number of features not found on other
switching regulator ICs. Its unique control circuitry can
maintain regulation well into discontinuous mode. Load
compensation circuitry allows for improved load regula-
tion. An externally activated shutdown mode reduces total
supply current to 20µA typical for standby operation.
, LTC and LT are registered trademarks of Linear Technology Corporation.
5V Output Isolated Power Supply
2 SHDN RCCOMP 7
C1, C2: AVX TPS D107M010R0080
T1: DALE LPE-4841-A307
1424-5 TA01 COM
100 200 300
OUTPUT CURRENT (mA)