A1698 Datasheet, PDF (1/13 Pages) Allegro MicroSystems – Two-Wire, True Zero-Speed, High Accuracy

A1698
Two-Wire, True Zero-Speed, High Accuracy
Sensor IC with Speed and Direction Output
FEATURES AND BENEFITS
• Integrated capacitor for EMC suppression in a single
overmolded miniature package
• Wide leads facilitate ease of assembly
• True zero-speed operation
• Pulse-width output protocol
• Automatic Gain Control (AGC) for air gap independent
switchpoints
• Automatic Offset Adjustment (AOA) for signal
processing optimization, providing large operating air
gap range
• Single chip sensing IC for high reliability
• Fully synchronous digital logic with Scan and IDDQ
testing
Package: 2-pin SIP (suffix UB)
DESCRIPTION
The A1698 is a Hall-effect-based integrated circuit (IC) that
provides a user-friendly solution for two-wire speed sensing of
ring magnets or ferrous targets (when back-biased by the user)
down to zero-speed in applications where speed and direction
is required. The A1698 is offered in the UB package, which
integrates the IC and a high temperature ceramic capacitor in
a single overmolded SIP package. The integrated capacitor
provides enhanced EMC performance.
The integrated circuit incorporates Hall-effect circuits and signal
processing that switches in response to differential magnetic
signals created by magnetic encoders, or, when properly back-
biased with a magnet, from ferromagnetic targets. The circuitry
contains a sophisticated digital circuit that reduces magnet
and system offsets, calibrates the gain for air gap independent
switchpoints, and provides true zero-speed operation.
The regulated current output is configured for two-wire interface
circuitry and is ideally suited for obtaining speed and direction
information in wheel speed applications. The 2-pin SIP package
is lead (Pb) free, with tin leadframe plating.
Not to scale
1
SUPPLY
Internal Regulator
Offset Gain
Adjust Adjust
Amp
Chopper
Stabilization
Amp
Offset Gain
Adjust Adjust
Filter
ADC
Filter
ADC
Digital
Controller
Output
Control
GROUND
2
A1698-DS, Rev. 2
Functional Block Diagram