ATS685LSHTN-T Allegro Microsystems Inc, ATS685LSHTN-T Datasheet

2-Wire, Zero Speed Differential Gear Tooth Sensor

ATS685LSHTN-T

Manufacturer Part Number
ATS685LSHTN-T
Description
2-Wire, Zero Speed Differential Gear Tooth Sensor
Manufacturer
Allegro Microsystems Inc
Series
-r
Type
Special Purposer
Datasheet

Specifications of ATS685LSHTN-T

Featured Product
ATS685 Sensor IC
Sensing Range
5mT ~ 150mT
Voltage - Supply
4 V ~ 24 V
Current - Supply
8mA
Current - Output (max)
-
Output Type
Digital, Open Drain
Features
Gear Tooth Type
Operating Temperature
-40°C ~ 150°C
Package / Case
4-SIP
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
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
Package: 4-pin SIP (suffix SH)
ATS685LSH-DS
and IDDQ measurement
Not to scale
VCC
Amp
Hall
Adjust
Offset
Regulator
Voltage
Functional Block Diagram
Synchronous Digital Controller
AGC
Differential Gear Tooth Sensor IC
GND
Description
The ATS685LSH 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.
PDAC
NDAC
Reference
Generator
Lockout
and
Two-Wire, Zero Speed
Multiplexor
ATS685LSH
TEST

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ATS685LSHTN-T Summary of contents

Page 1

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 ...

Page 2

... ATS685LSH Selection Guide Part Number ATS685LSHTN-T 13-in. reel, 800 pieces per reel *Contact Allegro ® for additional packing options Absolute Maximum Ratings Characteristic Supply Voltage Reverse Supply Voltage Operating Ambient Temperature Maximum Junction Temperature Storage Temperature Pin-out Diagram Terminal List Table ...

Page 3

ATS685LSH OPERATING CHARACTERISTICS Characteristics Electrical Characteristics Supply Voltage 3 Undervoltage Lockout Reverse Supply Current 4 Supply Zener Clamp Voltage Supply Zener Current Supply Current Supply Current Ratio / I Test Pin Zener Clamp Voltage 5 Power-On State Characteristics 6 Power-On ...

Page 4

ATS685LSH OPERATING CHARACTERISTICS (continued) Characteristics Functional Characteristics Operating Signal Range 11 Extended Operating Signal Range Operational Air Gap Range Extended Operational Air Gap Range Allowable User-Induced Differential B Offset 12 Duty Cycle Variation Maximum Sudden Signal Amplitude B Change 1 ...

Page 5

ATS685LSH Reference Target 60-0 (60 Tooth Target) Characteristics Symbol Outside Diameter D o Face Width F Angular Tooth Thickness t Angular Valley Thickness t v Tooth Whole Depth h t Material Reference Gear Magnetic Gradient Amplitude versus Air Gap Reference ...

Page 6

ATS685LSH may require derating at maximum conditions, see Power Derating section Thermal Characteristics Characteristic Package Thermal Resistance *Additional thermal information available on the Allegro website 2600 2400 2200 2000 1800 1600 1400 1200 1000 Differential Gear Tooth Sensor IC Symbol ...

Page 7

ATS685LSH Sensing Technology The ATS685 sensor IC contains a single-chip differential Hall- effect circuit, a samarium cobalt pellet, and a flat ferrous pole piece (a precisely-mounted magnetic field concentrator that homogenizes the flux passing through the Hall chip). As shown ...

Page 8

ATS685LSH Determining Output Signal Polarity In figure 2, the top panel, labeled Mechanical Position, represents the mechanical features of the target gear and orientation to the device. The bottom panel, labeled Device Output Signal, displays the square waveform corresponding to ...

Page 9

ATS685LSH Continuous Update of Switchpoints Switchpoints are the threshold levels of the differential internal analog signal which the device changes output signal PROC state. The value directly proportional to the magnetic flux PROC density, ...

Page 10

ATS685LSH Power-On The ATS685 is guaranteed to power-on in the high current state When power (V > V (min applied to the CC(High device, a short period of time is required to power the ...

Page 11

ATS685LSH Start Mode Hysteresis This feature helps to ensure optimal self-calibration by rejecting electrical noise and low-amplitude target vibration during initial- ization. This prevents AGC from calibrating the device on such spurious signals. Calibration can be performed using the actual ...

Page 12

ATS685LSH Undervoltage Lockout When the supply voltage falls below the minimum operating voltage goes high and remains high regardless of CC(UV) CC the state of the magnetic gradient from the target. This lockout feature prevents false signals, ...

Page 13

ATS685LSH The device must be operated below the maximum junction temperature of the device Under certain combinations of J(max) peak conditions, reliable operation may require derating supplied power or improving the heat dissipation properties of the appli- cation. ...

Page 14

ATS685LSH 1.10 F 8.00±0.05 5.80±0.05 E1 1.70±0.10 4.00±0.10 5.00±0. 24.65±0.10 13.10±0.10 A 5.50±0.10 Differential Gear Tooth Sensor IC Package SH, 4-Pin SIP 5.50±0.05 E 1.10 F Branded E2 Face 0.71±0.05 0.60±0.10 1.00±0.10 1.0 REF 1.60±0.10 ...

Page 15

ATS685LSH Copyright ©2011, Allegro MicroSystems, Inc. Allegro MicroSystems, Inc. reserves the right to make, from time to time, such de par tures from the detail spec tions as may be required to per- mit improvements in the ...

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