Dual Output Differential

Speed and Direction Sensor IC

ATS605LSG

10

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Under Voltage Lockout

When the supply voltage falls below the under voltage lockout

voltage, UVLO, the device enters Reset, where the output state

under voltage conditions, from propagating to the output of the

sensor.

Power Supply Protection

The device contains an on-chip regulator and can operate over a

lated power supply, transient protection must be added externally.

For applications using a regulated line, EMI/RFI protection may

still be required. Contact Allegro MicroSystems for information

on the circuitry needed for compliance with various EMC speci-

fications. Refer to Figure 7 for an example of a basic application

circuit.

Automatic Gain Control (AGC)

This feature allows the device to operate with an optimal internal

electrical signal, regardless of the air gap (within the AG speci-

fication). At power-on, the device determines the peak-to-peak

amplitude of the signal generated by the target. The gain of the

sensor is then automatically adjusted. Figure 6 illustrates the

effect of this feature.

Device Features

Automatic Offset Adjust (AOA)

The AOA circuitry automatically compensates for the effects of

chip, magnet, and installation offsets. (For capability, see Allow-

able User-Induced Magnetic Offset, in the Operating Character-

istics table.) This circuitry is continuously active, including both

during power-on mode and running mode, compensating for any

offset drift (within Allowable User-Induced Magnetic Offset).

Continuous operation also allows it to compensate for offsets

induced by temperature variations over time.

Lockout

The ATS605 has a lockout feature to prevent switching on small

signals that are characteristic of vibration signals. The internal

logic of the chip will consider small signal amplitudes below a

certain level to be vibration. The output will then be held to the

state prior to lockout until the amplitude of the signal returns to

normal operational levels. Lockout is independent between speed

channels for the SPEED and SPEED output configuration, allow-

ing one channel to continue switching without the other. The

alternative XOR SPEED and DIRECTION configuration requires

both channels to exceed the lockout release value before enabling

these output signals.

Assembly Description

The ATS605 is integrally molded into a plastic body that has

been optimized for size, ease of assembly, and manufacturability.

High operating temperature materials are used in all aspects of

construction.

Figure 6: Automatic Gain Control (AGC). The AGC function

corrects for variances in the air gap. Differences in the air gap

cause differences in the magnetic field at the device, but AGC

prevents that from affecting device performance, as shown in the

lower panel.

V

R

R

R

C

V

C

C

ATS605

GND

0.1 µF

V

CC

S

PULLUP(A)

PULLUP(B)

BYP

OUTB

LOAD(A)

LOAD(B)

1

3

4

2

OUTA

Figure 7: Typical Application Circuit