A1356: High Precision Linear Hall-Effect Sensor With an Open Drain Pulse Width Modulated Output

The A1356 device is a high precision, programmable open drain Hall-effect linear sensor IC with a pulse width modulated (PWM) output. The duty cycle (D) of the PWM output signal is proportional to an applied magnetic field. The A1356 device converts an analog signal from its internal Hall element to a digitally encoded PWM output signal. The coupled noise immunity of the digitally encoded PWM output is far superior to the noise immunity of an analog output signal.

The BiCMOS, monolithic circuit inside of the A1356 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. Hall element offset 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 signal and results in faster signal processing capability.

• Simultaneous programming of PWM carrier frequency, quiescent duty cycle, and sensitivity; for system optimization
• Factory programmed sensitivity temperature coefficient and quiescent duty cycle drift
• Programmability at end-of-line
• Pulse width modulated (PWM) output provides increased noise immunity compared to an analog output
• Precise recoverability after temperature cycling
• Output 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
• Advanced chopper stabilization circuits and differential signal path design lead to very low output offset levels
• Proprietary on-chip filters provide high output resolution
• Wide power supply operating range: 4.5 to 18 V