A8651: Low Input Voltage, Adjustable Frequency Dual Synchronous 2 A / 2 A Buck Regulator with Synchronization, 2x EN, and 2x NPOR


The A8651 is an adjustable frequency, high output current, PWM regulator that integrates a high-side, P-channel MOSFET and a low-side, N-channel MOSFET. The A8651 incorporates current-mode control to provide simple compensation, excellent loop stability, and fast transient response. The A8651 utilizes external compensation to accommodate a wide range of power components to optimize transient response without sacrificing stability. The A8651 regulates input voltages from 2.5 to 5.5 V, down to output voltages as low as 0.8 V and is able to supply up to 2 A of load current per regulator.

The A8651 features include an externally adjustable and synchronizable switching frequency, an externally-set soft start time to minimize inrush currents, independent EN inputs, and independent NPOR outputs with either 7.5 ms (A8651) or 120 μs (A8651-1) delay. The sleep mode current of the A8651 control circuitry is less than 5 μA.

Protection features include VIN undervoltage lockout (UVLO), cycle-by-cycle overcurrent protection (OCP), hiccup mode short-circuit protection (HIC), overvoltage protection (OVP), and thermal shutdown (TSD). In addition, the A8651 provides open-circuit, adjacent pin short-circuit, and short-to-ground protection at every pin to satisfy the most demanding automotive applications.

The A8651 device is available in a 20-pin TSSOP package with exposed thermal pad for enhanced thermal dissipation (suffix LP). It is lead (Pb) free, with 100% matte tin leadframe plating.


  • GPS/Infotainment
  • Automotive audio
  • Home audio
  • Network and telecom

Top Features

  • AEC-Q100 Qualified
  • Operating voltage range: 2.5 to 5.5 V
  • UVLO stop threshold: 2.25 V (max)
  • Dual outputs with up to 2 A output current per regulator
  • Adjustable output voltage as low as 0.8 V
  • Internal 80 mΩ high-side switching MOSFET
  • Internal 55 mΩ low-side switching MOSFET
  • Adjustable switching frequency ( fSW ): 0.35 to 2.2 MHz
  • Synchronizes to external clock: 1.2 × to 1.5 × fOSC
  • 180° phase shift between switching regulators
  • Sleep mode supply current less than 5 μA
  • Soft start time externally set via the SS pin
  • Pre-biased startup capable
  • Externally adjustable compensation
  • Stable with ceramic output capacitors
  • Independent enable inputs and NPOR output pins
  • NPOR delay of 7.5 ms (A8651) or 120 μs (A8651-1)
  • Adjustable current limiting (OCP) for each regulator
  • Hiccup mode short-circuit protection (HIC)
  • Overvoltage and overtemperature protection
  • Open-circuit and adjacent pin short-circuit tolerant
  • Short-to-ground tolerant at every pin

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Part Composition /
RoHS Data
Comments Samples Check Stock
APEK8651KLP-01-MH-1 n/a -20°C to 85°C -- View Data Contact your
local sales rep
Distributor Stock
A8651KLPTR-T 20-lead TSSOP -40°C to 125°C Yes View Data Discontinued Contact your
local sales rep
Distributor Stock
A8651KLPTR-T-1 20-lead TSSOP -40°C to 125°C Yes View Data 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.