A1351KKTTN-T Allegro Microsystems Inc, A1351KKTTN-T Datasheet - Page 13

• Manufacturer Part Number: A1351KKTTN-T
• Description: IC,HALL-EFFECT SENSOR,SINGLE-ENDED,BICMOS,SIP,4PIN,PLASTIC
• Manufacturer: Allegro Microsystems Inc
• Type: Linear - Unipolar, Bipolarr

Specifications of A1351KKTTN-T

• Sensing Range: 0.055% ~ 0.095% DC/G
• Voltage - Supply: 4.5 V ~ 5.5 V
• Current - Supply: 10mA
• Current - Output (max): 1mA
• Output Type: Digital, Push-Pull
• Features: High Precision
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 4-SIP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

A1351
When using Hall-effect technology, a limiting factor for
switchpoint accuracy is the small signal voltage developed
across the Hall element. This voltage is disproportionally small
relative to the offset that can be produced at the output of the
Hall element. This makes it difficult to process the signal while
maintaining an accurate, reliable output over the specified oper-
ating temperature and voltage ranges.
Chopper stabilization is a unique approach used to minimize
Hall offset on the chip. The patented Allegro technique, namely
Dynamic Quadrature Offset Cancellation, removes key sources
of the output drift induced by thermal and mechanical stresses.
This offset reduction technique is based on a signal modulation-
demodulation process.
The undesired offset signal is separated from the magnetic field-
induced signal in the frequency domain, through modulation.
The subsequent demodulation acts as a modulation process for
the offset, causing the magnetic field-induced signal to recover
Hall Element
with a Push/Pull, Pulse Width Modulated Output
C
0.1 μF
Chopper Stabilization Technique
Concept of Chopper Stabilization Technique
BYPASS
High Precision Linear Hall Effect Sensor IC
Typical Application Drawing
Regulator
V+
VCC
A135x
GND
PWMOUT
its original spectrum at base band, while the DC offset becomes
a high-frequency signal. The magnetic-sourced signal then can
pass through a low-pass filter, while the modulated DC offset is
suppressed. The chopper stabilization technique uses a 220 kHz
high frequency clock.
For demodulation process, a sample and hold technique is used,
where the sampling is performed at twice the chopper frequency
(440 kHz). This high-frequency operation allows a greater
sampling rate, which results in higher accuracy and faster signal-
processing capability. This approach desensitizes the chip to the
effects of thermal and mechanical stresses, and produces devices
that have extremely stable quiescent Hall output voltages and
precise recoverability after temperature cycling. This technique
is made possible through the use of a BiCMOS process, which
allows the use of low-offset, low-noise amplifiers in combination
with high-density logic integration and sample-and-hold circuits.
Clock/Logic
Amp
C
14.7 nF
L
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
Low-Pass
Filter
13