Document
ATS642LSH
Two-Wire True Zero Speed Miniature Differential Peak-Detecting Gear Tooth Sensor with Continuous Calibration
Features and Benefits
▪ Running mode calibration for continuous optimization ▪ Single chip IC for high reliability ▪ Internal current regulator for 2-wire operation ▪ Small mechanical size (8 mm diameter × 5.5 mm depth) ▪ Precise duty cycle signal over operating temperature range ▪ Large operating air gaps ▪ Automatic Gain Control (AGC) for air gap independent
switchpoints ▪ Automatic Offset Adjustment (AOA) for signal processing
optimization ▪ True zero-speed operation ▪ Undervoltage lockout ▪ Wide operating voltage range
Package: 4-pin Module (suffix SH)
Not to scale
Description
The ATS642LSH is an optimized Hall effect sensing integrated circuit and magnet combination that provides a user-friendly solution for true zero-speed digital gear-tooth sensing in twowire applications. The sensor consists of a single-shot molded plastic package that includes a samarium cobalt magnet, a pole piece, and a Hall effect IC that has been optimized to the magnetic circuit. This small package, with optimized two-wire leadframe, can be easily assembled and used in conjunction with a wide variety of gear shapes and sizes.
The integrated circuit incorporates a dual element Hall effect sensor and signal processing that switches in response to differential magnetic signals created by ferrous gear teeth. The circuitry contains a sophisticated digital circuit to reduce magnet and system offsets, to calibrate the gain for air gap independent switchpoints, and to achieve true zero-speed operation. Signal optimization occurs at power-up 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 allows immunity to environmental effects such as microoscillations of the target or sudden air gap changes. The regulated current output is configured for two wire applications and the sensor is ideally suited for obtain-
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Engineering samples available on a limited basis. Contact your local sales or applications support office for additional information.
Functional Block Diagram
Hall Amplifier
Gain
VCC
Automatic Offset Control
AOA DAC
Tracking DAC
Peak Hold
AGC DAC Gain Control
ATS684LSH-DS, Rev. 2 MCO-0000868
Internal Regulator Test Signals
GND Test
May 21, 2020
ATS642LSH
Two-Wire True Zero Speed Miniature Differential Peak-Detecting Gear Tooth Sensor with Continuous Calibration
Description (continued)
ing speed and duty cycle information in ABS (antilock braking systems). The 1.5 mm Hall element spacing is optimized for fine pitch gear-tooth-based configurations. The package is lead (Pb) free, with 100% matte tin leadframe plating.
Selection Guide
Part Number ATS642LSHTN-I1-T
ICC Typical 6.0 Low to 14.0 High mA
ATS642LSHTN-I2-T
7.0 Low to 14.0 High mA
*Contact Allegro™ for additional packing options
Packing* Tape and reel, 13-inch reel 800 pieces/reel
Absolute Maximum Ratings
Characteristic Supply Voltage Reverse_Supply Voltage Operating Ambient Temperature Maximum Junction Temperature Storage Temperature
Symbol VCC VRCC TA
TJ(max) Tstg
Range L
Notes
Rating
Unit
28
V
–18
V
–40 to 150
ºC
165
ºC
–65 to 170
ºC
Pin-out Diagram
12 3 4
Terminal List
Number
Name
1
VCC
2
NC
3
Test pin
4
GND
Function Connects power supply to chip No connection Float or tie to GND Ground terminal
2
Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com
ATS642LSH
Two-Wire True Zero Speed Miniature Differential Peak-Detecting Gear Tooth Sensor with Continuous Calibration
OPERATING CHARACTERISTICS using reference target 60-0, TA and VCC within specification, unless otherwise noted
Characteristic
Symbol
Test Conditions
Min.
Typ.1
Max.
Units
ELECTRICAL CHARACTERISTICS
Supply Voltage2 Undervoltage Lockout Supply Zener Clamp Voltage Supply Zener Current
Supply Current
VCC VCC(UV)
VZ
Operating; TJ < 165 °C VCC 0 → 5 V and 5 → 0 V ICC = ICC(max) + 3 mA; TA = 25°C
IZ
Test conditions only; VZ = 28 V
ATS642LSH-I1 ICC(Low) ATS642LSH-I2
ATS642LSH-I1 ICC(High) ATS642LSH-I2
4.0 – 28
–
4.0 5.9 12.0 11.8
–
24
V
–
4.0
V
–
–
V
–
ICC(max)+ 3 mA
mA
6.0
8.0
mA
7.0
8.4
mA
14.0
16.0
mA
14.0
16.8
mA
Supply Current Ratio Reverse Battery Current
/ ICC(High)
ICC(Low) IRCC
Ratio of high current to low current VRCC = –18 V
POWER-ON STATE CHARACTERISTICS
1.85
–
3.05
–
–
–
–5
mA
Power-On State3 Power-On Time4 OUTPUT STAGE
POS tPO
t > tPO Target gear speed < 100 rpm
–
ICC(High)
–
–
–
1
2
ms
Output Slew Rate5
dI/dt RLOAD = 100 Ω, CLOAD = 10 pF
–
10
–
mA/μs
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3
Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com
ATS642LSH
Two-Wire Tru.