A1356 Datasheet, PDF (1/20 Pages) Allegro MicroSystems – High Precision Linear Hall-Effect Sensor

A1356
High Precision Linear Hall-Effect Sensor
With an Open Drain Pulse Width Modulated Output
Features and Benefits
▪ 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
Package: 3-pin SIP (suffix KB)
Description
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 theA1356 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.
The A1356 sensor is provided in a lead (Pb) free 3-pin single
inline package (KB suffix), with 100% matte tin leadframe
plaiting.
Not to scale
VCC/
Programming
A1356-DS
Functional Block Diagram
Regulator
PWM Carrier
Generation
PWM
1
Frequency Trim
2
2
1
Chopper
Switches
Amp
Signal
Recovery
Signal
Conditioning
Sensitivity Temperature % Duty
Trim
Compensation ^Cycle
% Duty Cycle
Temperature
Coefficient
PWMOUT
GND