A1357: Two-Wire High Precision Linear Hall-Effect Sensor IC With Pulse Width Modulated Output Current

These parts are in production but have been determined to be NOT FOR NEW DESIGN. This classification indicates that sale of this device is currently restricted to existing customer applications. The device should not be purchased for new design applications because obsolescence in the near future is probable. Samples are no longer available. Date of status change: June 21, 2022.


The A1357 device is a high precision, programmable two-wire Hall-effect linear sensor IC with a pulse width modulated (PWM) current. The A1357 device converts an analog signal from its internal Hall sensor element to a digitally encoded PWM signal. The coupled noise immunity of the digitally encoded PWM is far superior to the noise immunity of an analog output signal.

The BiCMOS, monolithic circuit inside of the A1357 integrates a Hall element, precision temperature-compensating circuitry to reduce the intrinsic sensitivity and offset drift of the Hall element, a small-signal high-gain amplifier, proprietary dynamic offset cancellation circuits, and PWM conversion circuitry. The dynamic offset cancellation circuits reduce the residual offset voltage of the Hall element that is normally caused by device overmolding, temperature dependencies, and thermal stress. The high frequency offset cancellation (chopping) clock allows for a greater sampling rate, which increases the accuracy of the output current signal and results in faster signal processing capability.

The A1357 sensor is provided in a lead (Pb) free 3-pin single inline package (KB suffix), with 100% matte tin leadframe plating.

Top Features

  • Two-wire output enables reduced wiring costs in long wire systems
  • Simultaneous programming of PWM carrier frequency, quiescent duty cycle (QDC), and sensitivity for system optimization
  • Fully differential signal path increases EMC immunity and reduces output offset drifts
  • Factory programmed sensitivity temperature coefficient and quiescent duty cycle drift
  • Programmability at end-of-line
  • Pulse width modulated (PWM) current output provides increased noise and EMC immunity compared to an analog output
  • Precise recoverability after temperature cycling Duty cycle clamps provide short circuit diagnostic capabilities
  • Optional 50% duty cycle calibration test mode at device power up
  • Wide ambient temperature range: –40°C to 150°C
  • Resistant to mechanical stress

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Part Composition /
RoHS Data
Comments Samples Check Stock
A1357LKB-T 3-lead SIP -40°C to 150°C Yes View Data Not for new design Contact your
local sales rep
Distributor Stock
A1357LKBTN-T 3-lead SIP -40°C to 150°C -- View Data New 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.

Hall Effect Linear Sensor A1356 Packaging Image


The A1357 sensor is provided in a lead (Pb) free 3-pin single inline package (KB suffix), with 100% matte tin leadframe plating.

KB Package Documentation