Two-Wire, Differential, Vibration-Resistant Sensor

with Speed and Direction Output

ATS699LSN

10

Allegro MicroSystems, LLC

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

TIMING

As shown in Figure 6, the pulse appears at the output slightly

before the sensed magnetic edge traverses the package branded

face. For targets rotating from pin 3 to 1, this shift (Δfwd with R

variants) results in the pulse corresponding to the valley with the

sensed mechanical edge; for targets rotating from pin 1 to 3, the

shift (Δrev) results in the pulse corresponding to the tooth with

the sensed edge. Figure 7 shows pulse timing for F variants. The

sensed mechanical edge that stimulates output pulses is kept the

same for both forward and reverse rotation by using only one

channel to control output switching.

Direction Validation

For the -xxxxL variant, following a direction change in run-

ning mode, direction changes are immediately transmitted to the

output.

For the -xxxxH variant, following a direction change in running

mation is validated.

Valley

Tooth

Pin 3 to 1 Rotation

Pin 1 to 3 Rotation

Output Pulse

(Pin 3 to 1 Rotation)

Output Pulse

(Pin 1 to 3 Rotation)

t

fwd

rev

t

w(FWD)

t

w(REV)

Figure 6: Output Protocol (-RSxxx Variant)

Output Pulse

(Pin 3 to 1 Rotation)

Output Pulse

(Pin 1 to 3 Rotation)

t

fwd

rev

t

w(FWD)

t

w(REV)

Figure 7: Output Protocol (-FDxxx Variant)

Target

Differential

Magnetic

Profile

t

t

w(FWD)

t

w(FWD)

t

w(REV)

t

w(REV)

Target Rotation Forward

Target Rotation Reverse

Valley

Tooth

Figure 8: Running Mode Direction Change (-FSxxL Variant)

Target

Differential

Magnetic

Profile

t

t

w(FWD)

t

w(FWD)

t

w(ND)

t

w(REV)

Target Rotation Forward

Target Rotation Reverse

Valley

Tooth

Figure 9: Running Mode Direction Change (-FSxxH Variant)