A1469 Datasheet, PDF (1/15 Pages) Allegro MicroSystems – Three-Wire True Zero-Speed Differential Peak-Detecting Sensor IC with Continuous Calibration

A1469
Three-Wire True Zero-Speed Differential Peak-Detecting
Sensor IC with Continuous Calibration
FEATURES AND BENEFITS
• Unique design for robustness against high power EMC
transients
• Peak detection based switching algorithm for large
operating air gaps
• Minimum differential field 20 G_pk-pk
• Running mode calibration for continuous optimization
• Precise duty cycle signal throughout operating
temperature range
• Automatic Gain Control (AGC) for air-gap–independent
switchpoints
• Automatic Offset Adjustment (AOA) for signal
processing optimization
• True zero-speed operation
• Scan and IDDQ for increased test coverage
PACKAGE:
4-pin SIP (suffix K)
Not to scale
DESCRIPTION
The A1469 is an optimized Hall effect sensing IC that provides
a user-friendly solution for digital ring-magnet sensing, or
when coupled with a magnet, ferromagnetic target sensing,
in three-wire applications. The small device package can be
easily assembled into applications for use in conjunction with
a wide variety of target shapes and sizes.
The integrated circuit incorporates dual Hall effect elements
with a 2.2 mm spacing and signal processing that switches
in response to differential magnetic signals created by ring-
magnet poles. The circuitry contains a sophisticated digital
circuit to reduce system offsets, to calibrate the gain for air-
gap–independent switchpoints, and to achieve true zero-speed
operation. Signal optimization occurs at power-on through
the combination of offset and gain adjust, and is maintained
throughout the operating time with the use of a running-mode
calibration. The running-mode calibration provides immunity
to environmental effects such as micro-oscillations of the target
or sudden air gap changes.
The device is ideally suited to obtaining speed and duty cycle
information in ring-magnet–based speed, position, and timing
applications, such as in speedometers.
The A1469 is available in a 4-pin SIP (suffix K) package. The
package is lead (Pb) free, with 100% matte tin leadframe plating.
VCC
E1
Hall
Amplifier
E2
Automatic Offset
Adjustment (AOA)
Control
∑
AOA DAC
Gain
Internal
Regulator
A1469-DS
Automatic Gain
Control (AGC)
AGC DAC
Test Signals
TEST
Tracking DAC
Peak Hold
+
–
Functional Block Diagram
Current
Limit
OUT
GND