A1684LUB Datasheet, PDF (1/15 Pages) Allegro MicroSystems – Air gap independent switchpoints

A1684LUB
Two-Wire, Zero-Speed, High Accuracy
Differential Sensor IC
FEATURES AND BENEFITS
• Integrated capacitor reduces requirement for external
EMI protection component
• Fully optimized differential digital ring magnet and
gear tooth sensor IC
• Running Mode Lockout
• Unique algorithms to assist in mitigation of system
anomalies such as vibration
• AGC and reference adjust circuit
• Air gap independent switchpoints
• Digital output representing target mechanical profile
• Precise duty cycle throughout operating temperature
range
• Short power-on time
• True zero-speed operation
• Undervoltage lockout (UVLO)
• Wide operating voltage range
• Internal current regulator for two-wire operation
• Robust test coverage capability using Scan Path
and IDDQ measurement
• AEC-Q100 automotive qualified
Package: 2-pin SIP (suffix UB)
Not to scale
DESCRIPTION
The A1684LUB is an optimized Hall-effect sensing integrated
circuit that provides a user-friendly solution for true zero-speed
digital ring magnet and, when magnetically back-biased, gear-
tooth sensing in two-wire applications. The Hall-effect IC has
been optimized for the automotive environment. This small
package can be used in conjunction with a wide variety of
target shapes and sizes.
The single integrated circuit incorporates a dual element Hall
effect sensor IC and signal processing circuitry that switches
in response to differential magnetic signals created by a ring
magnet, or by a rotating ferromagnetic target when used in
combination with a back-biasing magnet. The device contains
a sophisticated compensating circuit to eliminate magnetic and
system offsets. Digital tracking of the analog signal is used
to achieve true zero-speed operation. Advanced calibration
algorithms are used to adjust the device gain and offset at
power-up, resulting in air gap independent switchpoints, which
greatly improves output accuracy. In addition, advanced running
mode calibration circuits mitigate the effect of system anomalies
such as target vibration and sudden changes in air gap.
The regulated current output is configured for two-wire
operation. When configured with a back-biasing magnet, this
sensor IC is ideal for obtaining edge and duty cycle information
in gear-tooth–based applications such as transmission speed.
The A1684 is provided in a 2-pin miniature SIP package (suffix
UB) that is lead (Pb) free, with 100% matte tin leadframe plating.
VCC
Voltage
Regulator
Hall
Amp
Offset
Adjust
AGC
PDAC
NDAC
Reference
Generator
and
Lockout
Synchronous Digital Controller
A1684LUB-DS, Rev. 7
GND
Functional Block Diagram
November 8, 2016