A8672: Fixed Frequency High Current Synchronous Buck Regulator With Fault Warnings and Power OK


The A8672 is a synchronous buck converter capable of delivering up to 8 A. The A8672 utilizes valley current mode control, allowing very short on-times to be achieved. This makes it ideal for applications that require very low output voltages relative to the input voltage, combined with high switching frequencies. Valley current mode control inherently provides improved transient response over traditional switcher schemes, through the use of a voltage feedforward loop and frequency modulation during large signal load changes.

The A8672 includes a comprehensive set of diagnostic flags, allowing the host platform to react to a myriad of different conditions. A fault output indicates when either the temperature is becoming unusually high, or a single point failure has occurred; for example, the switching node (LX) shorted to ground, or the timing resistor going open-circuit. A Power OK (POK) output is also provided after a fixed delay, to indicate when the output voltage is within regulation. The selectable pulse-by-pulse current limit avoids the requirement to oversize the inductor to cope with large fault currents.

The device package (EG) is a 28-contact, 4 mm × 5 mm, 0.75 mm nominal overall height QFN with exposed thermal pad. The package is lead (Pb) free, with 100% matte tin leadframe plating.


  • Servers
  • Network and telecom
  • Point of load supplies
  • Storage

This part is discontinued. Samples are no longer available. Date of status change: September 1, 2016. Recommended Substitutions: For existing customer transition, and for new customers or new applications, contact Allegro Sales.

Top Features

  • High efficiency integrated FETs optimized for lower duty cycle voltage conversion: 27 mΩ high side, 12 mΩ low side
  • Power input voltage range: 3 to 16 V
  • Control input voltage range: 4.5 to 16 V
  • Adjustable output voltage, down to 0.6 V
  • 5 V LDO Regulator
  • Extremely short minimum controllable on-time; example: allows 12 V conversion to 0.6 V at >1 MHz
  • Reference accuracy of ±1% throughout temperature range
  • FAULT and Power OK pins for operating and protection modes
  • Low power mode (LPM) or fixed continuous conduction mode (FCCM) operation
  • Programmable soft-start / hiccup shutdown period
  • Ultra-fast transient response

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Part Composition /
RoHS Data
Comments Samples Check Stock
A8672EEGTR-T 28-lead QFN -40°C to 85°C -- View Data Discontinued Contact your
local sales rep
Distributor Stock

Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro’s product can reasonably be expected to cause bodily harm.