Green mode Quasi-resonant ICs


  • Status:Available

FA5571 is a quasi-resonant switching power supply control IC with excellent standby characteristics. Despite its compact 8-pin package, it has a wide variety of functions and reduces the number of external components, thereby enabling the configuration of space-saving and cost-effective power supplies.


  • Quasi-resonant switching power supply
  • Power supply with excellent standby characteristics
  • Incorporates a startup circuit to achieve low power consumption
  • Low current consumption of 1.35 mA during operation
  • Built-in maximum frequency limiting function: 120 kHz
  • Light-load operation: Built-in burst function
  • Built-in drive circuit that can directly connect power MOSFETs
    1. Output current: 0.5 A (sink) / 0.25 A (source)
  • Built-in overload protection: Spring return
  • Built-in latch protection with secondary overvoltage detection
  • Built-in transformer short-circuit protection
  • Built-in low-voltage malfunction prevention circuit (18 V ON/8 V OFF)
  • Package: SOP-8


  • Switching Power Supplies


Controller type QR
Applied circuit Detail Flyback
Frequency (kHz) Selfoscillation (Max.120kHz)
VCC(V) 10 to 28
Built-in start up circuit (V) 500
Over load protection Auto-Recovery
Over voltage protection Latch (ZCD)
Package SOP-8

Documentation Tools

Selection Guide Power Supply Control IC Selection Guide



Block diagram

Circuit diagram

Outline drawing

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