High-Accuracy, Pulse-Width or AK Protocol

Hall-Effect Wheel Speed and Direction Sensor IC

A19302

14

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

ASIL Safe State Output Protocol

The A19302 is being developed in accordance with

ISO 26262:2011 (2018) as a hardware safety element out of

context targeting ASIL B(D) capability for use in automotive

safety-related systems when integrated and used in the manner

prescribed in the applicable safety manual and datasheet.

The -xxx-A variant enables diagnostic circuitry that will continu-

ously monitor occurrences of failure defects within the IC. Refer

to Figure 14 for the output protocol of the ASIL safe state after an

internal defect has been detected. Error Protocol will result from

faults which cause incorrect signal transmission (i.e., too few or

too many output pulses).

Note: If a fault exists continuously, the device will stay in perma-

nent safe state. Refer to the A19302 Safety Manual for additional

details on the ASIL Safe State Output Protocol.

N

S

N

Magne�c

Encoder

ICC(HIGH)

ICC(LOW)

ICC(HIGH)

S

N

Output

Events

(Normal

Opera�on)

ICC(LOW)

Fault

Protocol

(PW)

Fault

Protocol

(AK)

Error

Error

ICC(MID)

ICC(MID)

IFAULT

IFAULT

I

tw(FAULT)

tCAL

tw(FAULT)

tCAL

Figure 14: Output Protocol (ASIL Safe State)