A3946: Half-Bridge Power MOSFET Controller

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The A3946 is designed specifically for applications that require high power unidirectional DC motors, three-phase brushless DC motors, or other inductive loads. The A3946 provides two high-current gate drive outputs that are capable of driving a wide range of power N-channel MOSFETs. The high-side gate driver switches an N-channel MOSFET that controls current to the load, while the low-side gate driver switches an N-channel MOSFET as a synchronous rectifier.

A bootstrap capacitor provides the above-battery supply voltage required for N-channel MOSFETs. An internal top-off charge pump for the high side allows DC (100% duty cycle) operation of the half-bridge.

Allegro recommended automotive qualified hall latches: APS122x5 and APS122x0


  • On-chip charge pump for 7 V minimum input supply voltage
  • High-current gate drive for driving a wide range of N-channel MOSFETs
  • Bootstrapped gate drive with charge pump for 100% duty cycle
  • Overtemperature protection
  • Undervoltage protection
  • -40°C to 135°C ambient operation

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Part Composition /
RoHS Data
Comments Samples Check Stock
A3946KLPTR-T 16-lead TSSOP -40°C to 135°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.



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