ATS675 datasheet(5/14 Pages) ALLEGRO

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Self-Calibrating TPOS Speed Sensor IC

Optimized for Automotive Cam Sensing Applications

ATS675LSE

Allegro MicroSystems, LLC

115 Northeast Cutoff

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

1.508.853.5000; www.allegromicro.com

Calibration7

Initial Calibration12,13

CALI

Quantity of mechanical falling edges used to

determine Running mode switchpoints level

–

edge

TPO to Running Mode Adjustment

CALTPORM

Quantity of mechanical falling edges after CALI

to transition from TPOS switchpoints level to

Running mode switchpoints level

–

tooth

Running Mode Switchpoint Characteristics

Running Mode Switchpoint

BST

% of peak-to-peak, referenced to tooth signal

(see figure 4)

–30

–

%pk–pk

Internal Hysteresis

BHYS(int)

% of peak-to-peak signal

–

Signal Characteristics

Maximum Allowable Signal Reduction14

Breduce

Reduction in VPROC amplitude from VPROC(high)

to lowest peak VPROC(reduce), all specifications

within range (see figure 3)

–

%pk-pk

Reduction in VPROC amplitude from VPROC(high)

to lowest peak VPROC(reduce); output switches,

other specifications may be out of range (see

figure 3)

–

%pk-pk

Relative Timing Accuracy12,15

ErrRELR

Rising mechanical edges after initial calibration,

gear speed = 1000 rpm, target eccentricity

< 0.1 mm

–

0.4

0.8

deg.

ErrRELF

Falling mechanical edges after initial calibration,

gear speed = 1000 rpm, target eccentricity

< 0.1 mm

–

0.5

1.0

deg.

1Typical values are at TA = 25°C and VCC = 12 V. Performance may vary for individual units, within the specified maximum and minimum limits.

2Maximum voltage must be adjusted for power dissipation and junction temperature; see Power Derating section.

3Maximum current limit is equal to ICC(max) + 3 mA.

4Negative current is defined as conventional current coming out of (sourced from) the specified device terminal.

5Sustained voltages beyond the clamp voltage may cause permanent damage to the IC.

6Power-On Time is the duration from when VCC rises above VCC(min) until a valid output state is realized.

7For additional information see the Functional Description section.

8Characterization data shows 12 V fall time to be 1.5 times longer than 5 V fall time. See figure 2.

9Output Delay Time is the duration from when a crossing of the magnetic signal switching level, BST, occurs to when the electrical output signal, VOUT ,

reaches 90% of VOUT(high).

10The Operational Air Gap Range is the range of installation air gaps within which the TPOS (True Power-On State) function is guaranteed to correctly

detect a tooth when powered-on opposite a tooth and correctly detecting a valley when powered-on opposite a valley, using reference target 8X.

11The Extended Air Gap Range is a range of installation air gaps, larger than AGTPOS, within which the device will accurately detect target features in

Running mode, but TPOS functionality is NOT guaranteed, possibly resulting in undetected target features during Initial Calibration. Relative Timing

Accuracy (ErrREL) not guaranteed in Extended Air Gap Range.

12The term mechanical edge refers to a target feature, such as the side of a gear tooth, passing opposite the device. A rising edge is a transition from a

valley to a tooth, and a falling edge is a transition from a tooth to a valley. See figure 6.

13Signal frequency for CALI is fSIG < 200 Hz.

14Running mode; 4X target used. The Processed Internal Signal, VPROC, is the internal signal generated by the Hall detection circuitry and normalized

by Automatic Gain Control.

15Relative Timing Accuracy refers to the difference in accuracy, relative to a 0.5 mm air gap, through the entire Operational Air Gap Range, after initial

calibration; gear speed = 1000 rpm, target eccentricity < 0.1 mm. See figure 7.

OPERATING CHARACTERISTICS (continued) Valid using reference target 8X, T

A, TJ, and VCC within specification, unless otherwise noted

Characteristics

Symbol

Test Conditions

Min.

Typ.1

Max.

Unit

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