ATS685 Datasheet, PDF (1/15 Pages) Allegro MicroSystems – Two-Wire, Zero Speed Differential Gear Tooth Sensor IC

ATS685LSH
Two-Wire, Zero Speed
Differential Gear Tooth Sensor IC
Features and Benefits
• Fully optimized differential digital gear tooth sensor IC
• Running Mode Lockout
• Unique algorithms for increased vibration immunity
• AGC and reference adjust circuit
• Air gap independent switchpoints
• Digital output representing gear profile
• Precise duty cycle throughout operating temperature range
• Large operating air gap range
• Short power-on time
• True zero-speed operation
• Undervoltage lockout (UVLO)
• Wide operating voltage range
• Internal current regulator for two-wire operation
• Single-chip sensing IC for high reliability
• Robust test coverage capability using Scan Path
and IDDQ measurement
Package: 4-pin SIP (suffix SH)
Not to scale
Description
TheATS685LSH is an optimized Hall-effect sensing integrated
circuit and rare-earth pellet combination that provides a
user-friendly solution for true zero-speed digital gear-tooth
sensing in two-wire applications. The sensor IC consists of a
single-shot molded plastic package that includes a samarium
cobalt pellet, a pole piece, and a Hall Effect IC that has been
optimized to the magnetic circuit. This small package can be
easily assembled and used in conjunction with a wide variety
of gear 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 ferromagnetic targets. 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 algorithms 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. This sensor IC is ideal for obtaining edge and duty
cycle information in gear-tooth–based applications such as
transmission speed.
The ATS685 is provided in a 4-pin SIP package that is lead
(Pb) free, with 100% matte tin leadframe plating.
Functional Block Diagram
VCC
Voltage
Regulator
Hall
Amp
Offset
Adjust
AGC
PDAC
NDAC
Reference
Generator
and
Lockout
ATS685LSH-DS
Synchronous Digital Controller
GND
Multiplexor
TEST