60V, No-Opto Isolated Flyback Controller

Compact, Cost-Effective, and Easy-to-Implement Isolated DC-DC Controller


The MAX17690 is a peak current mode, fixed-frequency switching controller specifically designed for the isolated flyback topology operating in Discontinuous Conduction Mode (DCM). The device senses the isolated output voltage directly from the primary-side flyback waveform during the off-time of the primary switch. No auxiliary winding or optocoupler is required for output voltage regulation.

The MAX17690 is designed to operate over a wide supply range from 4.5V to 60V. The switching frequency is programmable from 50kHz to 250kHz. A EN/UVLO pin allows the user to turn on/off the power supply precisely at the desired input voltage. The MAX17690 provides an input overvoltage protection through the OVI pin. The 7V internal LDO output of the MAX17690 makes it suitable for switching both logic-level and standard MOSFETs used in flyback converters. With 2A/4A source/sink currents, the MAX17690 is ideal for driving low RDS(ON) power MOSFETs with fast gate transition times. The MAX17690 provides an adjustable soft-start feature to limit the inrush current during startup.

The MAX17690 provides temperature compensation for the output diode forward voltage drop. The MAX17690 has robust hiccup-protection and thermal protection schemes, and is available in a space-saving 16-pin 3mm x 3mm TQFN package with a temperature range from -40°C to 125°C.
MAX17690: Functional Block Diagram MAX17690: Functional Block Diagram Enlarge+

Key Features

  • 4.5V to 60V Input Voltage Range
  • No Optocoupler or Third Winding Required to Derive Feedback Signal Across Isolation Boundary
  • 2A/4A Peak Source/Sink Gate Drive Currents
  • 50kHz to 250kHz Programmable Switching Frequency
  • Input EN/UVLO Feature
  • Input Overvoltage Protection
  • Programmable Soft-Start
  • Hiccup-Mode Short-Circuit Protection
  • Thermal Shutdown Protection
  • -40°C to 125°C Operating Temperature Range
  • Space-Saving, 16-Pin 3 x 3 TQFN Package


  • Industrial and Telecom Applications
  • Isolated Flyback Converters
  • PLC I/O Modules
  • Wide-Range DC-Input Isolated Power Supplies
Part Number Application (VIN) VIN
Topology Switch Type Feedback Freq.
Duty Cycle
Gate Drive Current
Oper. Temp.
Package/Pins Budgetary
min max max max max max See Notes
MAX17690 NEW!
Base Station (24V)
Industrial (24V)
Networking (48V)
4.5 60 Flyback External Primary Side 250 69 1.8 1.8 2 -40 to +125
$2.99 @1k
See All Isolated Power Supplies (24)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

MAX17690EVKITA: Evaluation Kit for the MAX17690
MAX17690EVKITB: Evaluation Kit for the MAX17690

Quality and Environmental Data

Product Reliability Reports: MAX17690.pdf 
Lead-Free Package Tin (Sn) Whisker Reports

Additional Resources

Topmark Coding MAX17690

Related Resources