FTM Board Club
3A, 40V Synchronous Step-Down COT Regulator PowerBlox™

The XR76203 is a synchronous step-down regulator combining the controller, drivers, bootstrap diode and MOSFETs in a single package for point-of-load supplies.

The XR76203 has a load current rating of 3A. A wide 3.0V to 40V input voltage range allows for single supply operation from industry standard 24V ±10%, 18V-36V, and rectified 18VAC and 24VAC rails.

With a proprietary emulated current mode Constant On-Time (COT) control scheme, the XR76203 provides extremely fast line and load transient response using ceramic output capacitors. It requires no loop compensation, simplifying circuit implementation and reducing overall component count. The control loop also provides 0.07% load and 0.15% line regulation and maintains constant operating frequency. A selectable power saving mode allows the user to operate in Discontinuous Conduction Mode (DCM) at light current loads thereby significantly increasing the converter efficiency.

A host of protection features, including overcurrent, over temperature, short-circuit and UVLO, helps achieve safe operation under abnormal operating conditions.

The XR76203 is available in a RoHS-compliant, green/halogen-free space-saving QFN 5 x 5mm package.

  • Controller, drivers, bootstrap diode and MOSFETs integrated in one package
  • 3A step-down regulator
  • Wide 5.0V to 40V input voltage range
    • 3V to 40V PVIN with 5V bias
    • 4.5 to 5.5V single supply operation
    • ≥0.6V adjustable output voltage
  • Proprietary constant on-time control
    • No loop compensation required
    • Stable ceramic output capacitor operation
    • Programmable 200ns to 2µs on-time
    • Constant 100kHz to 800kHz frequency
  • Selectable CCM or CCM/DCM
    • CCM/DCM for high efficiency at light-load
    • CCM for constant frequency at light-load
  • Programmable hiccup current limit with thermal compensation
  • Precision enable and power good flag
  • Programmable soft-start
  • 30-pin 5 x 5mm QFN package
  • Pin compatible 5A regulator, XR76205
  • Pin compatible 8A regulator, XR76208