The ISL6721EVAL3Z evaluation board serves as a reference design for a single switch resonant reset forward converter with multiple outputs for typical industry applications that need isolation. It can be used for security monitoring systems where an input voltage range of 21.6V to 52.8V is typical for operation from a battery source of 24V or 48V with 10% tolerance.

The ISL6721 is a high performance single-ended PWM controller intended for various isolated and non-isolated applications for telecom power supply, server power and industrial power supply.


  • Switching frequency: Fsw: 300kHz
  • Input voltage range, VIN: 21.6V DC to 52.8V DC
  • Output voltage 1, VOUT1: 12V with 5% absolute regulation
  • Output current 1, IOUT1: 2.5A
  • Output voltage 2, VOUT2: 18V with 5% absolute regulation
  • Output current 2, IOUT2: 1A
  • Overall output power, POUT: 48W
  • Full load efficiency: 80% under all line and load conditions
  • Output voltage ripple: 50mVP-P on each rail
  • Minimum load: 25% on 12V rail, 20% on 18V output


  • Telecom and datacom power
  • Wireless basestation power
  • File server power
  • Industrial power systems
  • Isolated buck and flyback regulators
  • Boost regulators