Exar – XR77128: Quad Channel Digital Programmable Power Management System IC


The XR77128 is a quad channel Digital Pulse Width Modulated (DPWM) step down (buck) controller. With integrated FET gate drivers, two LDOs for stand-by power and a 105kHz to 1.23MHz independent channel to channel programmable constant operating frequency, the XR77128 reduces overall component count and solution footprint and optimizes conversion efficiencies. A selectable Digital Pulse Frequency Mode (DPFM) capable of better than 80% efficiency at light current load and low operating current allow for portable and Energy Star compliant applications. Each XR77128 output channel is individually programmable as low as 0.6V with a resolution as fine as 2.5mV.


  • DrMOS and/or MOSFET drive capability
  • Quad channel step down controller
  • SMBus compliant I2C interface
  • Arduino development system
  • Full start/stop sequencing support
  • Built-in thermal, overcurrent, UVLO and output over-voltage protections
  • 4.75V to 25V input voltage
  • Digital PWM 105kHz to 1.23MHz operation
  • Supported by PowerArchitect 5.2 or later version
  • 3 x 15V capable PSIO + 2 x GPIOs
  • 1k MSRP: $7.75 US