ATS645LSHTN-I1 - Allegro Microsystems

NOTE: For detailed information on purchasing options, contact your

local Allegro field applications engineer or sales representative.

Allegro MicroSystems, Inc. reserves the right to make, from time to time, revisions to the anticipated product life cycle plan

for a product to accommodate changes in production capabilities, alternative product availabilities, or market demand. The

information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no respon-

sibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use.

Recommended Substitutions:

Two-Wire True Zero Speed Miniature Differential

Peak-Detecting Gear Tooth Sensor IC

ATS645LSH

Date of status change: January 2, 2009

These parts are in production but have been determined to be

NOT FOR NEW DESIGN. This classification indicates that sale of

this device is currently restricted to existing customer applications.

The device should not be purchased for new design applications

because obsolescence in the near future is probable. Samples are no

longer available.

Not for New Design

Description

The components in speed sensing applications continue to

diminish in size to meet spatial constraints and weight reduction

requirements. As the geometries of gears become smaller, this

can compromise the capabilities of a gear speed sensor. The

ATS645 Hall-element-to-Hall-element spacing of only 1.5 mm

makes this device uniquely capable of accommodating very

fine-pitch gears. In addition, the ATS645 signal peak-detecting

algorithm supports consistent switching at relatively large air

gaps, where the peak-to-peak amplitude is small. These features

make the ATS645 the ideal solution to detect the speed of fine-

pitch targets such as those found in ABS (antilock braking)

systems.

The ATS645 combines a Hall-effect sensing integrated circuit

and rare earth pellet to provide a manufacturer-friendly solution

for true zero-speed digital gear-tooth sensing in two-wire

applications. The device consists of a single-shot molded

plastic package that includes a samarium cobalt pellet, a

pole piece, and a Hall-effect integrated circuit that has been

optimized to the magnetic circuit. This small package can be

easily assembled and used in conjunction with a wide variety

of gear shapes and sizes.

ATS645-DS, Rev. 6

Features and Benefits

• Fully optimized differential digital gear tooth sensor IC

• Single chip IC for high reliability

• Internal current regulator for 2-wire operation

• Small mechanical size (8 mm diameter x 5.5 mm depth)

• Air gap independent switchpoints

• Digital output representing gear profile

• Precise duty cycle signal over operating temperature range

• Large operating air gaps

• Automatic Gain Control (AGC)

• Automatic Offset Adjustment (AOA)

Two-Wire True Zero Speed Miniature Differential

Peak-Detecting Gear Tooth Sensor IC

Continued on the next page…

Functional Block Diagram

Not to scale

Packages: 4 pin SIP (suffix SH)

ATS645LSH

Continued on the next page…

VCC

Automatic Offset

Control AOA DAC

Hall

Amplifier

AGC DAC

Gain

Tracking

DAC Peak Hold

Internal Regulator

Test Signals

GND

Test

True Zero Speed Miniature Dif ferential Peak-

Detecting Gear Tooth Sensor IC

ATS645LSH

Allegro MicroSystems, Inc.

115 Northeast Cutoff

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

1.508.853.5000; www.allegromicro.com

• True zero-speed operation

• Undervoltage lockout

• Wide operating voltage range

• Defined power-on state

The integrated circuit incorporates a dual-element Hall effect circuit

as well as signal processing that switches the output state in response

to changes in the magnetic gradients created by ferromagnetic

gear teeth. The circuitry contains a sophisticated digital circuit to

eliminate magnet and system offsets and to achieve true zero speed

operation (U.S. Patent 5,917,320). A-D and D-A converters are

used to adjust the device gain at power-on and to allow switching

independent of the breadth of the air gap.

The regulated current output is configured for two wire applications,

requiring one less wire for operation than do switches with the more

traditional open-collector output. The package is available in a lead

(Pb) free version, with 100% matte tin leadframe plating.

Part Number Packing*ICC Typical

ATS645LSHTN-I1-T Tape and Reel 13-in. 800 pcs./reel 6.0 Low to 14.0 High mA

ATS645LSHTN-I2-T Tape and Reel 13-in. 800 pcs./reel 7.0 Low to 14.0 High mA

*Contact Allegro for additional packing options. Some restrictions may apply to certain types of sales. Contact

Allegro for details.

Features and Benefits (continued) Description (continued)

Absolute Maximum Ratings

Characteristic Symbol Notes Rating Units

Supply Voltage VCC 28 –

Reverse-Supply Voltage VRCC –18 V

Operating Ambient Temperature TARange L –40 to 150 ºC

Maximum Junction Temperature TJ(max) 165 ºC

Storage Temperature Tstg –65 to 170 ºC

Terminal List

Name Description Number

VCC Connects power supply to chip 1

NC No connection 2

TEST For Allegro use, ﬂ oat or tie to GND 3

GND Ground terminal 4

Pin-out Diagram

True Zero Speed Miniature Dif ferential Peak-

Detecting Gear Tooth Sensor IC

ATS645LSH

Allegro MicroSystems, Inc.

115 Northeast Cutoff

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

1.508.853.5000; www.allegromicro.com

OPERATING CHARACTERISTICS using reference target 60-0, TA and VCC within speciﬁ cation, unless otherwise noted

CHARACTERISTIC Symbol Test Conditions Min. Typ.1Max. Units

ELECTRICAL CHARACTERISTICS

Supply Voltage2VCC Operating; TJ < 165 °C 4.0 – 24 V

Undervoltage Lockout VCC(UV) VCC 0 → 5 V and 5 → 0 V – – 4.0 V

Supply Zener Clamp Voltage VZICC = ICC(max) + 3 mA; TA = 25°C 28 – – V

Supply Zener Current IZTest conditions only; VZ = 28 V – – ICC(max)+

3 mA mA

Supply Current

ICC(Low)

ATS645LSH-I1 4.0 6 8.0 mA

ATS645LSH-I2 5.9 7 8.4 mA

ICC(High)

ATS645LSH-I1 12.0 14.0 16.0 mA

ATS645LSH-I2 11.8 14.0 16.8 mA

Supply Current Ratio ICC(High)/

ICC(Low)

Ratio of high current to low current 1.85 – 3.05 –

POWER-ON STATE CHARACTERISTICS

Power-On State POS t > tPO –I

CC(High) ––

Power-On Time3tPO Target gear speed < 100 rpm – 1 2 ms

OUTPUT STAGE

Output Slew Rate4dI/dt RLOAD = 100 Ω, CLOAD = 10 pF – 10 – mA/μs

Continued on the next page.

True Zero Speed Miniature Dif ferential Peak-

Detecting Gear Tooth Sensor IC

ATS645LSH

Allegro MicroSystems, Inc.

115 Northeast Cutoff

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

1.508.853.5000; www.allegromicro.com

OPERATING CHARACTERISTICS (continued) using reference target 60-0, TA and VCC within speciﬁ cation, unless otherwise noted

Characteristic Symbol Test Conditions Min. Typ.1Max. Units

SWITCHPOINT CHARACTERISTICS

Rotation Speed SROT Reference Target 60-0 0 – 8,000 rpm

Analog Signal Bandwidth BW Equivalent to f – 3dB 20 40 – kHz

Operate Point BOP

Transitioning from ICC(High) to ICC(Low); positive peak

referenced; AG < AGMAX

– 120 – mV

Release Point BRP

Transitioning from ICC(Low) to ICC(High); negative peak

referenced; AG < AGMAX

– 120 – mV

CALIBRATION

Initial Calibration CI

Quantity of rising output (current) edges required for

accurate edge detection – – 3 Edge

DAC CHARACTERISTICS

Allowable User-Induced Differential

Offset

Output switching only; may not meet datasheet speci-

ﬁ cations –60 – 60 G

FUNCTIONAL CHARACTERISTICS5

Operational Air Gap Range6AG ∆DC within speciﬁ cation 0.5 – 2.75 mm

Maximum Operational Air Gap

Range AGOP(max)

Output switching (no missed edges); ∆DC not

guaranteed ––3mm

Duty Cycle Variation7∆DC Wobble < 0.5mm; Typical value at AG = 1.5 mm, for

max., min., AG within speciﬁ cation 43 53 63 %

Operating Magnetic Flux Density

Differential8BAG(p-p) Operating within speciﬁ cation 30 – 1000 G

Minimum Operating Signal SigOP(min)

Output switching (no missed edges); ∆DC not

guaranteed 20 – – G

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

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

3Power-On Time includes the time required to complete the internal automatic offset adjust. The DACs are then ready for peak acquisition.

4dI is the difference between 10% of ICC(Low) and 90% of ICC(High), and dt is time period between those two points.

Note: di/dt is dependent upon the value of the bypass capacitor, if one is used.

5Functional characteristics valid only if magnetic offset is within the speciﬁ ed range for Allowable User Induced Differential Offset.

6AG is dependent on the available magnetic ﬁ eld. The available ﬁ eld is dependent on target geometry and material, and should be independently

characterized. The ﬁ eld available from the reference target is given in the reference target parameter section of the datasheet.

7Duty cycle speciﬁ cation may not be met if the magnetic signal during the calibration period is not representative of the installation air gap.

8In order to remain in speciﬁ cation, the magnetic gradient must induce an operating signal greater than the minimum value speciﬁ ed. This includes the

effect of target wobble.

True Zero Speed Miniature Dif ferential Peak-

Detecting Gear Tooth Sensor IC

ATS645LSH

Allegro MicroSystems, Inc.

115 Northeast Cutoff

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

1.508.853.5000; www.allegromicro.com

REFERENCE TARGET, 60-0 (60 Tooth Target)

Characteristics Symbol Test Conditions Typ. Units Symbol Key

Outside Diameter DoOutside diameter of target 120 mm

Face Width F Breadth of tooth, with respect to

branded face 6mm

Circular Tooth Length t Length of tooth, with respect to

branded face; measured at Do

3mm

Circular Valley Length tv

Length of valley, with respect to

branded face; measured at Do

3mm

Tooth Whole Depth ht3mm

Material Low Carbon Steel – –

Reference Gear Magnetic Gradient Amplitude

With Reference to Air Gap

Air Gap (mm)

Peak-to-Peak Differential B (G)

100

200

300

400

500

600

700

800

11.520.5 2.5 3

Reference Gear Magnetic Profile

Two Tooth-to-Valley Transitions

-500

-400

-300

-200

-100

100

200

300

400

500

Gear Rotation (°)

Differential B* (G)

024681012

0.50

(mm)

Air Gap

0.50 mm AG

3.00 mm AG

0.75

1.00

1.25

1.50

1.75

2.00

2.25

2.50

2.75

3.00

of Package

Reference Target

60-0

of Package

Branded Face

*Differential B corresponds to the calculated difference in the magnetic ﬁ eld as

sensed simultaneously at the two Hall elements in the device (BDIFF = BE1 – BE2).

True Zero Speed Miniature Dif ferential Peak-

Detecting Gear Tooth Sensor IC

ATS645LSH

Allegro MicroSystems, Inc.

115 Northeast Cutoff

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

1.508.853.5000; www.allegromicro.com

Characteristic Data

I1 Trim

Duty Cycle vs. Air Gap

100 RPM, VCC = 12 V

0 0.5 1 1.5 2 2.5 3 3.5

Air Gap (mm)

Duty Cycle (%)

Duty Cycle vs. Air Gap

1000 RPM, V

= 12 V

0 0.5 1 1.5 2 2.5 3 3.5

Air Gap (mm)

Duty Cycle (%)

Duty Cycle vs. Target Speed

Air Gap 1.5 mm, V

= 12 V

0 200 400 600 800 1000 1200 1400 1600

Target Speed (RPM)

Duty Cycle (%)

Supply Current vs. Supply Voltage

0 5 10 15 20 25 30

VCC (V)

ICC (mA)

ICC(High)

ICC(Low)

, (ºC)

-40

150

, (ºC)

-40

150

, (ºC)

-40

150

, (ºC)

-40

150

True Zero Speed Miniature Dif ferential Peak-

Detecting Gear Tooth Sensor IC

ATS645LSH

Allegro MicroSystems, Inc.

115 Northeast Cutoff

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

1.508.853.5000; www.allegromicro.com

THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information

CHARACTERISTIC Symbol TEST CONDITIONS* Value Units

Package Thermal Resistance RθJA

Single-layer PCB with copper limited to solder pads 126 ºC/W

Two-layer PCB with 3.8 in.2 of copper area on each side con-

nected with thermal vias and to device ground pin 84 ºC/W

*Additional information is available on the Allegro Web site.

20 40 60 80 100 120 140 160 180

Temperature (ºC)

Maximum Allowable V

(V)

TJ(max) = 165ºC; ICC = ICC(max)

Power Derating Curve

θJA

= 126 ºC/W)

θJA

= 84 ºC/W)

VCC(min)

VCC(max)

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

20 40 60 80 100 120 140 160 180

Temperature (°C)

Power Dissipation, P

(mW)

TJ(max) = 165ºC; VCC = VCC(max); ICC = ICC(max)

Maximum Power Dissipation, PD(max)

θJA

= 126 ºC/W)

(RθJA = 84 ºC/W)

True Zero Speed Miniature Dif ferential Peak-

Detecting Gear Tooth Sensor IC

ATS645LSH

Allegro MicroSystems, Inc.

115 Northeast Cutoff

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

1.508.853.5000; www.allegromicro.com

Hall Technology

The gear tooth sensor IC subassembly contains a single-chip

differential Hall effect sensor IC, an optimized samarium cobalt

pellet, and a ﬂ at ferrous pole piece. The Hall IC supports two

Hall elements, which sense the magnetic proﬁ le of the ferromag-

netic target simultaneously, but at different points (spaced at a

1.5 mm pitch), generating a differential internal analog voltage

(VPROC) that is processed for precise switching of the digital

output signal.

The Hall IC is self-calibrating and also possesses a tempera-

ture compensated ampliﬁ er and offset cancellation circuitry. Its

voltage regulator provides supply noise rejection throughout the

operating voltage range. Changes in temperature do not greatly

affect this device due to the stable ampliﬁ er design and the offset

rejection circuitry. The Hall transducers and signal processing

electronics are integrated on the same silicon substrate, using a

proprietary BiCMOS process.

Target Profiling

An operating device is capable of providing digital information

that is representative of the mechanical features on a rotating

target. The waveform diagram shown in ﬁ gure 3 presents the

automatic translation of the mechanical proﬁ le, through the mag-

netic proﬁ le that it induces, to the digital output signal of the IC.

Output Polarity

Figure 3 shows the output polarity for the orientation of target

and package shown in ﬁ gure 2. The target direction of rota-

tion shown is: perpendicular to the leads, across the face of the

device, from the pin 1 side to the pin 4 side. This results in the

IC output switching from high, ICC(High), to low ICC(Low), as the

leading edge of a tooth (a rising mechanical edge, as detected by

the IC) passes the package face. In this conﬁ guration, the device

output current switches to its low polarity when a tooth is the

target feature nearest to the package. If the direction of rotation

is reversed, then the output polarity inverts.

Note that output voltage polarity is dependent on the position of

the sense resistor, RSENSE (see ﬁ gure 4).

Target (Gear)

Back-biasing

Rare-earth Pellet

South Pole

North Pole Case

(Pin 1 Side)(Pin 4 Side)

Hall IC

Pole Piece

Element Pitch

(Concentrator)

Dual-Element

Hall Effect Device

Hall Element 1

Hall Element 2

of Package

Rotating Target Branded Face

Functional Description

Figure 1. Relative motion of the target is detected by the dual Hall ele-

ments mounted on the Hall IC.

Figure 2. This left-to-right (pin 1 to pin 4) direction of target rotation

results in a low output signal when a tooth of the target gear is nearest

the face of the package (see ﬁ gure 3). A right-to-left (pin 4 to pin 1) rota-

tion inverts the output signal polarity. Figure 4: Voltages proﬁ les for high side and low side two-wire sensing.

Figure 3. Output Proﬁ le of a ferrous target for the polarity indicated in

ﬁ gure 2.

ATS645

VCC

GND

VCC

ICC

VOUT(L)

ATS645

VCC

GND

VCC

VOUT(H)

ICC

RSENSE

OUT

OUT(H)

V+

OUT(L)

V+

I+

Representative

Differential

Magnetic Profile

Target

Mechanical Profile

IC Electrical

Output Profile, I

OUT

True Zero Speed Miniature Dif ferential Peak-

Detecting Gear Tooth Sensor IC

ATS645LSH

Allegro MicroSystems, Inc.

115 Northeast Cutoff

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

1.508.853.5000; www.allegromicro.com

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-

ﬁ cation). During calibration, the device determines the peak-to-

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

of the IC is then automatically adjusted. Figure 5 illustrates the

effect of this feature.

Automatic Offset Adjust (AOA)

The AOA is patented circuitry that automatically cancels the

effects of chip, magnet, and installation offsets. (For capability,

see Dynamic Offset Cancellation, in the Operating Characteris-

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

during calibration mode and running mode, compensating for

any offset drift. Continuous operation also allows it to compen-

sate for offsets induced by temperature variations over time.

Digital Peak Detection

A digital DAC tracks the internal analog voltage signal VPROC,

and is used for holding the peak value of the internal analog

signal. In the example shown in ﬁ gure 6, the DAC would ﬁ rst

track up with the signal and hold the upper peak’s value. When

VPROC drops below this peak value by BOP, the device hyster-

esis, the output would switch and the DAC would begin tracking

the signal downward toward the negative VPROC peak. Once the

DAC acquires the negative peak, the output will again switch

states when VPROC is greater than the peak by the value BRP. At

this point, the DAC tracks up again and the cycle repeats. The

digital tracking of the differential analog signal allows the IC to

achieve true zero-speed operation.

Figure 5. Automatic Gain Control (AGC). The AGC function corrects for

variances in the air gap. Differences in the air gap affect the magnetic

gradient, but AGC prevents that from affecting device performance, a

shown in the lowest panel.

Mechanical Profile

Small

Large

Small

Large

Internal Differential

Analog Signal

Response, with AGC

Internal Differential

Analog Signal

Response, without AGC

Ferrous Target

V+

Figure 6: Peak Detecting Switchpoint Detail

Device

Output Current

Internal

Differential

Analog Signal

V+

I+

True Zero Speed Miniature Dif ferential Peak-

Detecting Gear Tooth Sensor IC

ATS645LSH

Allegro MicroSystems, Inc.

115 Northeast Cutoff

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

1.508.853.5000; www.allegromicro.com

Power Supply Protection

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

a wide VCC range. For devices that need to operate from an

unregulated power supply, transient protection must be added

externally. For applications using a regulated line, EMI/RFI pro-

tection may still be required. Contact Allegro MicroSystems for

information on the circuitry needed for compliance with various

EMC speciﬁ cations. Refer to ﬁ gure 7 for an example of a basic

application circuit.

Undervoltage Lockout

When the supply voltage falls below the undervoltage lockout

voltage, VCC(UV), the device enters Reset, where the output state

returns to the Power-On State (POS) until sufﬁ cient VCC is sup-

plied. ICC levels may not meet datasheet limits when

VCC < VCC(min).

Assembly Description

This device 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 7: Typical Application Circuit

ATS645

VCC

GND

V+

0.01

µF

ECU

Pins 2 and 3 floating

100 Ω

SENSE

CBYP

True Zero Speed Miniature Dif ferential Peak-

Detecting Gear Tooth Sensor IC

ATS645LSH

Allegro MicroSystems, Inc.

115 Northeast Cutoff

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

1.508.853.5000; www.allegromicro.com

DEVICE OPERATION

Each operating mode is described in detail below.

Power-On

When power (VCC > VCCMIN) is applied to the device, a short

period of time is required to power the various portions of the

IC. During this period, the ATS645 is guaranteed to power-on in

the high current state, ICC(High).

Initial Offset Adjust

The IC intially cancels the effects of chip, magnet, and installa-

tion offsets. Once offsets have been cancelled, the digital track-

ing DAC is ready to track the signal and provide output switch-

ing. The period of time required for both Power-On and Initial

Offset Adjust is deﬁ ned as the Power-On Time.

Calibration Mode

The calibration mode allows the IC to automatically select

the proper signal gain and continue to adjust for offsets. The

AGC is active, and selects the optimal signal gain based on the

amplitude of the VPROC signal. Following each adjustment to

the AGC DAC, the Offset DAC is also adjusted to ensure the

internal analog signal is properly centered.

During this mode, the tracking DAC is active and output switch-

ing occurs, but the duty cycle is not guaranteed to be within

speciﬁ cation.

Diagnostics

The regulated current output is conﬁ gured for two wire appli-

cations, requiring one less wire for operation than do switches

with the more traditional open-collector output. Additionally,

the system designer inherently gains diagnostics because there

is always output current flowing, which should be in either of

two narrow ranges. Any current level not within these ranges

indicates a fault condition.

Running Mode

After the initial calibration period, CI, during which a signal

gain is established, the device moves to Running mode. Dur-

ing Running mode, the IC tracks the input signal and gives an

output edge for every peak of the signal. AOA remains active to

compensate for any offset drift over time.

True Zero Speed Miniature Dif ferential Peak-

Detecting Gear Tooth Sensor IC

ATS645LSH

Allegro MicroSystems, Inc.

115 Northeast Cutoff

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

1.508.853.5000; www.allegromicro.com

Power Derating

The device must be operated below the maximum junction

temperature of the device, TJ(max). Under certain combinations of

peak conditions, reliable operation may require derating sup-

plied power or improving the heat dissipation properties of the

application. This section presents a procedure for correlating

factors affecting operating TJ. (Thermal data is also available on

the Allegro MicroSystems Web site.)

The Package Thermal Resistance, RJA, is a ﬁ gure of merit sum-

marizing the ability of the application and the device to dissipate

heat from the junction (die), through all paths to the ambient air.

Its primary component is the Effective Thermal Conductivity,

K, of the printed circuit board, including adjacent devices and

traces. Radiation from the die through the device case, RJC, is

relatively small component of RJA. Ambient air temperature,

TA, and air motion are signiﬁ cant external factors, damped by

overmolding.

The effect of varying power levels (Power Dissipation, PD), can

be estimated. The following formulas represent the fundamental

relationships used to estimate TJ, at PD.

PD = VIN × IIN (1)

 T = PD × RJA (2)

TJ = TA + ΔT (3)

For example, given common conditions such as: TA= 25°C,

VCC = 12 V, ICC = 4 mA, and RJA = 140 °C/W, then:

D = VCC × ICC = 12 V × 4 mA = 48 mW

T = PD × RJA = 48 mW × 140 °C/W = 7°C

J = TA + T = 25°C + 7°C = 32°C

A worst-case estimate, PD(max), represents the maximum allow-

able power level (VCC(max), ICC(max)), without exceeding TJ(max),

at a selected RJA and TA.

Example: Reliability for VCC at TA =

150°C, package SH

(I1 trim), using minimum-K PCB

Observe the worst-case ratings for the device, speciﬁ cally:

RJA

126°C/W, TJ(max) =

165°C, VCC(max)

V, and

ICC(max) = 16

mA.

Calculate the maximum allowable power level, PD(max). First,

invert equation 3:

Tmax = TJ(max) – TA = 165

°C

–

150

°C = 15

°C

This provides the allowable increase to TJ resulting from internal

power dissipation. Then, invert equation 2:

PD(max) = Tmax ÷ RJA = 15°C ÷ 126 °C/W = 119 mW

Finally, invert equation 1 with respect to voltage:

VCC(est) = PD(max) ÷ ICC(max) = 119 mW ÷ 16 mA = 7 V

The result indicates that, at TA, the application and device can

dissipate adequate amounts of heat at voltages ≤VCC(est).

Compare VCC(est) to VCC(max). If VCC(est) ≤ VCC(max), then reli-

able operation between VCC(est) and VCC(max) requires enhanced

RJA. If VCC(est) ≥ VCC(max), then operation between VCC(est) and

VCC(max) is reliable under these conditions.

True Zero Speed Miniature Dif ferential Peak-

Detecting Gear Tooth Sensor IC

ATS645LSH

Allegro MicroSystems, Inc.

115 Northeast Cutoff

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

1.508.853.5000; www.allegromicro.com

Package SH SIP

0.71±0.05

5.00±0.10 4.00±0.10

1.00±0.10

0.60±0.10

24.65±0.10

13.10±0.10

1.0 REF

0.71±0.10 0.71±0.10

1.60±0.10

1.27±0.10

5.50±0.10

5.50±0.05

8.00±0.05

5.80±0.05

1.70±0.10

243

For Reference Only, not for tooling use (reference DWG-9003)

Dimensions in millimeters

Dambar removal protrusion (16X)

Metallic protrusion, electrically connected to pin 4 and substrate (both sides)

Thermoplastic Molded Lead Bar for alignment during shipment

Active Area Depth 0.43 mm REF

Branded

Face

Standard Branding Reference View

= Supplier emblem

L = Lot identifier

N = Last three numbers of device part number

Y = Last two digits of year of manufacture

W = Week of manufacture

LLLLLLL

YYWW

NNN

Branding scale and appearance at supplier discretion

0.38 +0.06

–0.04 E

E2E1

0.75

Hall elements (E1, E2); not to scale

For the latest version of this document, visit our website:

www.allegromicro.com

The products described herein are manufactured under one or more of the following U.S. patents: 5,264,783; 5,389,889; 5,442,283; 5,517,112;

5,581,179; 5,619,137; 5,621,319; 5,650,719; 5,686,894; 5,694,038; 5,729,130; 5,917,320; 6,091,239; 6,100,680; 6,232,768; 6,242,908; 6,265,865;

6,297,627; 6,525,531; 6,690,155; 6,693,419; 6,919,720; 7,046,000; 7,053,674; 7,138,793; 7,199,579; 7,253,614; 7,365,530; 7,368,904; or other

patents pending.

Allegro MicroSystems, Inc. reserves the right to make, from time to time, such de par tures from the detail spec i fi ca tions as may be required to per-

mit improvements in the per for mance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the

information being relied upon is current.

Allegro’s products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the

failure of that life support device or system, or to affect the safety or effectiveness of that device or system.

The in for ma tion in clud ed herein is believed to be ac cu rate and reliable. How ev er, Allegro MicroSystems, Inc. assumes no re spon si bil i ty for its use;

nor for any in fringe ment of patents or other rights of third parties which may result from its use.