ATS685LSH
Two-Wire, Zero Speed
Differential Gear Tooth Sensor IC
Description
Features and Benefits
Fully optimized differential digital gear tooth sensor IC
The ATS685LSH is an optimized Hall-effect sensing integrated
Running Mode Lockout
circuit and rare-earth pellet combination that provides a
Unique algorithms for increased vibration immunity
user-friendly solution for true zero-speed digital gear-tooth
AGC and reference adjust circuit
sensing in two-wire applications. The sensor IC consists of a
Air gap independent switchpoints
single-shot molded plastic package that includes a samarium
Digital output representing gear profile
cobalt pellet, a pole piece, and a Hall Effect IC that has been
Precise duty cycle throughout operating temperature range
optimized to the magnetic circuit. This small package can be
Large operating air gap range
easily assembled and used in conjunction with a wide variety
Short power-on time
of gear shapes and sizes.
True zero-speed operation
The single integrated circuit incorporates a dual element
Undervoltage lockout (UVLO)
Hall-effect sensor IC and signal processing circuitry that
Wide operating voltage range
switches in response to differential magnetic signals created
Internal current regulator for two-wire operation
by ferromagnetic targets. The device contains a sophisticated
Single-chip sensing IC for high reliability
compensating circuit to eliminate magnetic and system offsets.
Robust test coverage capability using Scan Path
Digital tracking of the analog signal is used to achieve true
and IDDQ measurement
zero speed operation. Advanced calibration algorithms are
Package: 4-pin SIP (suffix SH)
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-toothbased applications such as
transmission speed.
Not to scale
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
PDAC
Reference
Offset
Hall Generator
AGC
Amp Adjust and
Lockout
NDAC
Synchronous Digital Controller
TEST
Multiplexor
GND
ATS685LSH-DSTwo-Wire, Zero Speed
ATS685LSH
Differential Gear Tooth Sensor IC
Selection Guide
Part Number Packing*
ATS685LSHTN-T 13-in. reel, 800 pieces per reel
*Contact Allegro for additional packing options
Absolute Maximum Ratings
Characteristic Symbol Notes Rating Units
Supply Voltage V 26.5 V
CC
Reverse Supply Voltage V 18 V
RCC
Operating Ambient Temperature T Range L, refer to Power Derating Curve 40 to 150 C
A
Maximum Junction Temperature T (max) 165 C
J
Storage Temperature T 65 to 170 C
stg
Pin-out Diagram
Terminal List Table
Number Name Function
1 VCC Supply voltage
2 NC No connection (float or tie to GND)
3 TEST Test (float or tie to GND)
4 GND Ground
1243
Allegro MicroSystems, LLC
2
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com