ASIL-Compliant Hall-Effect Wheel Speed Sensor IC

with Speed and Direction Output

A19300

6

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

Characteristic

Symbol

Test Conditions

Min.

Typ.[1]

Max.

Unit

OPERATING CHARACTERISTICS AND PERFORMANCE

Operating Frequency,

Forward Pulses [8]

fFWD

-xNxx variant

0

–

5

kHz

-xWxx variant

0

–

3.9

kHz

Operating Frequency,

Reverse Pulses [8]

fREV

-xNxx and -xWxx variant

0

–

2.4

kHz

Operating Frequency,

Warning Pulses

fWARN

-xxPx variant

0

–

5

kHz

Operating Differential Magnetic

Input [9]

BDIFF(pk-pk)

Peak-to-peak of differential magnetic input

20

–

–

G

Operating Differential Magnetic

Range [9]

BDIFF

Refer to Figure 5

–700

–

700

G

Air Gap Warning Level

BWARN

Signal amplitude that engages warning pulses

(-xxPx variant)

–

24

–

G

Operating Magnetic Input

Signal Variation

∆BDIFF(pk-pk)

Bounded amplitude ratio within TWINDOW [10];

no missed output transitions or flat line condition;

possible incorrect direction information;

see Figure 3 and Figure 4

0.4

–

–

–

Operating Magnetic Input

Signal Window

TWINDOW

Rolling window where ∆BDIFF(pk-pk) cannot exceed

bounded ratio; see Figure 3 and Figure 4

4 ×

TCYCLE

–

–

–

Calibration Period

TCAL

Period between power-on and valid speed and

correct direction output (f ≤ 200 Hz)

–

–

1.5 ×

TCYCLE

–

Operate Point

BOP

% of peak-to-peak IC-processed signal

–

60

–

%

Release Point

BRP

% of peak-to-peak IC-processed signal

–

40

–

%

Switch Point Separation

BDIFF(SP-SEP)

Required amount of amplitude separated

between channels at each BOP and BRP

occurrence and channels must be in phase

(refer to Figure 6)

20

–

–

%pk-pk

THERMAL CHARACTERISTICS

Magnetic Temperature Coefficient [11]

TC

Based on ferrite ring magnet and neodymium

magnet (-xxxE Variant)

–

0.16

–

%/°C

Based on SmCo magnet (-xxxG variant)

–

0.04

–

%/°C

[1]

Typical values are at TA = 25°C and VCC = 12 V. Performance may vary for individual units, within the specified maximum and minimum limits.

[2]

Maximum voltage must be adjusted for power dissipation and junction temperature; see representative for Power Derating discussions.

[3]

Negative current is defined as conventional current coming out of (sourced from) the specified device terminal.

[4]

Supply current ratio is taken as a mean value of ICC(HIGH) / ICC(LOW).

[5]

Output Rise/Fall Time specification is guaranteed by design.

[6]

Time between power-on to ICC stabilizing. Transitions prior to tPO should be ignored.

[7]

Pulse width measured at threshold of (ICC(HIGH) + ICC(LOW)) / 2.

[8]

These frequency ranges are based on valid pulse width generation with each pulse width preceding with a tw(PRE)(MAX). Frequency is based on BDIFF frequency.

[9]

Differential magnetic field is measured for Channel A (E1-E2) and Channel B (E2-E3) independently. Refer to Figure 5. Each channel’s differential magnetic field is

measured between two Hall elements spaced by 1.5 mm. Magnetic field is measured orthogonally to the front of the package. Refer to UB package drawing.

[10]

Symmetrical signal variation is defined as the largest amplitude ratio from Bn to Bn + TWINDOW. Signal variation may occur continuously while BDIFF remains in the

operating magnetic range.

[11]

Magnetic encoders decrease in magnetic strength with rising temperature. The device temperature coefficient compensates, maintaining the BDIFF(pk-pk) requirement.

OPERATING CHARACTERISTICS (continued): Valid throughout full operating and temperature ranges,

unless otherwise specified