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The SDH8666Q is a quasi-resonant current mode PWM+PFM controller with high-voltage startup, built-in high voltage power MOSFET, and external sensing resistor, is applicable to SMPS applications. 

The SDH8666Q integrates a high-voltage startup constant current source, features low standby power dissipation (<40mW). At heavy load conditon, it operates in QR mode to reduce switch loss in the high line input voltage, and it operates with fixed frequency (65KHz) in CCM mode in the low line input voltage. At medium load or light load conditons, it works in QR+PFM mode to improve the conversion efficiency. At no load conditon, it enters burst mode to reduce the standby power dissipation.

The SDH8666Q has frequency jitter function to improve EMI performance. The available peak current compensation function ensures the limit output power consistency even with different AC input voltages. The soft startup reduces the device stress during power-on process.

The SDH8666Q integrates complete protections including VCC overvoltage protection, output over-load protection, output overvoltage protection, leading edge blanking, cycle-by-cycle peak current limit, AC input voltage undervoltage protection and over temperature protection, etc.

SDH8666Q supports adapter applications up to 36W.

Main feature
  • High-voltage startup

  • Low standby power dissipation<40mW 

  • QR mode for low EMI and low switch loss

  • PFM mode at light load condition for higher conversion efficiency

  • Entering burst mode at no load condition

  • Frequency rising at low voltage and heavy load condition for high limit output powerw  Frequency jitter for low EMI 

  • Peak current compensation

  • Soft startup 

  • VCC overvoltage protection

  • Output overload protection

  • Leading edge blanking

  • Cycle-by-cycle current limit

  • Output diode short protection

  • Undervoltage protection for AC input voltage

  • Adjustable output overvoltage protection 

  • Over temperature protection

Ordering Information
Product Name Package form Marking Hazardous Substance Control Packing Type Remarks
SDH8666Q EHSOP-5-325-1.7 SDH8666Q Halogen free Tube
SDH8666QTR EHSOP-5-325-1.7 SDH8666Q Halogen free Tape & Reel
Block Diagram


title Types of Size (KB) date Download the latest English version
SDH8666Q PDF 124 2020-10-23 SDH8666Q Datasheet