The ISL6401 pulse width modulating (PWM) current mode controller is designed for a wide range of DC/DC conversion applications including boost, flyback and isolated output configurations. The device is optimized to provide a high performance, low-cost solution for Ringing SLIC (RSLIC), Ring (Vbh) and Talk (Vbl) power supplies in VoIP applications. The IC features an integrated inverter that is ideal for generating negative output voltages like RSLIC Ring Vbh (-72V) and Talk Vbl (-24V), -48V for IP phones, -5V and -15V for DSL CO line drivers. The output voltages are adjusted with an external voltage divider.

The ISL6401EVAL1Z evaluation board is shipped "ready to use" right from the box. The IC requires +5V bias. The evaluation board input voltage can be 10V to 16V with the specified transformer and external components. The output voltages are -24V at 120mA and -72V at 120mA. The board is capable of evaluating device operation with loads that simulate one, two, three, or four line operation. The use of an electronic load enables evaluation over a wide range of operating conditions. Simply vary the load on each output from 0mA to 120mA in any combination to match exact application requirements.


  • Positive and negative output regulation
  • Starting supply current: 100µA (typ.)
  • Quiescent current: 55µA (typ.)
  • Output frequency range: 50kHz to 600kHz
  • External clock synchronization
  • Fast transient response with peak current mode control
  • Internal soft-start
  • Drives N-channel MOSFET
  • Logic level shutdown
  • Leading edge blanking
  • 1% tolerance voltage reference over line and temperature
  • Pb-free available (RoHS compliant)


  • VoIP/VoDSL ringer and off-hook voltage generators
  • Multi-output flyback supplies
  • Cable and DSL modems
  • Set-top boxes
  • Wireless local loops
  • LMDH and FTTH supplies
  • Boost regulators
  • Routers

Documentation & Downloads

Title language Type Format File Size Date
Datasheets & Errata
ISL6401 Datasheet Datasheet PDF 681 KB
User Guides & Manuals
ISL6401EVAL1Z User Guide Manual PDF 506 KB
Application Notes & White Papers
AN1681: Grounding Techniques Application Note PDF 509 KB
AN1684: Nonideality of Ground Application Note PDF 397 KB
ISL6752DBEVAL1Z, ISL6754DBEVAL1Z Design Files Design File ZIP 2.45 MB
ISL6742BEVAL3Z Design Files Design File ZIP 448 KB