ATS605LSGTN-S-T - ALLEGRO MICROSYSTEMS

DESCRIPTION

The ATS605LSG provides a single IC solution to rotational

position sensing applications with a ferrous gear target.

The SG package incorporates a rare-earth pellet for ease of

manufacturing, consistent performance over temperature, and

enhanced reliability.

Three Hall elements are incorporated to create two independent

differential channels. These channels are processed by the

IC which contains a sophisticated digital circuit designed

to eliminate the detrimental effects of magnet and system

offsets. Hall differential signals are used to produce a highly

accurate speed output and, if desired, provide information on

the direction of rotation.

Advanced calibration techniques are used to optimize signal

offset and amplitude. This calibration, combined with the

digital tracking of the signal, results in accurate switch points

over air gap, speed, and temperature. The open-drain outputs

provide voltage output signals which mirror the sensed target’s

shape, with a phase separation between the two channels

proportionate to the size of the target teeth versus the Hall

element spacing. This sensor IC system is optimized for a

variety of applications requiring dual phase gear speed and

position signal information or simultaneous high-resolution

gear speed and direction information.

The ATS605 is offered in a lead (Pb) free 4-pin SIP package

with an integrated back-biasing magnet with a 100% matte-

tin-plated leadframe.

ATS605LSG-DS, Rev. 4

MCO-0000216

FEATURES AND BENEFITS

• Two independent digital outputs representing the sensed

target’s mechanical profile

• Optional output with high-resolution position and direc-

tion detection information

• Air gap independent switch points

• Integrated back-biasing magnetic circuit

• Immunity to external magnetic interference

• Wide operating voltage range

• Single chip IC for high reliability

• Robust test coverage and reliability using Scan and

IDDQ test methodologies

• Optional Double-Bandwidth configuration

Dual Output Differential Speed and Direction Sensor IC

PACKAGE: 4-PIN SIP (SUFFIX SG)

ATS605LSG

Not to scale

Functional Block Diagram

July 3, 2019

Hall Amp

VCC

REGULATOR

(Analog)

REGULATOR

(Digital)

OFFSET

ADJUST

OFFSET

ADJUST

AGC

FILTER

ADC

XOR SPEED

SPEED B

SPEED A

DIRECTION

Current

Limit

Current

Limit

OUT A

OUT B

GND

SYNCHRONOUS

DIGITAL

CONTROLLER

ADC

MULTIPLEXED

SIGNALS

MULTIPLEXED

SIGNALS

Hall Amp

Dual Output Differential Speed and Direction Sensor IC

ATS605LSG

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

ABSOLUTE MAXIMUM RATINGS

Characteristic Symbol Notes Rating Unit

Supply Voltage VCC Refer to Power Derating section 28 V

Reverse Supply Voltage VRCC –18 V

Reverse Supply Current IRCC –50 mA

Reverse Output Voltage VROUT –0.5 V

Forward Output Voltage VOUT 28 V

Output Sink Current IOUTSINK

Internal current limiting is intended to protect the device from

output short circuits, but is not intended for continuous opera-

tion.

25 mA

Operating Ambient Temperature TAL temperature range –40 to 150 °C

Maximum Junction Temperature TJ(max) 165 °C

Storage Temperature Tstg –65 to 170 °C

SELECTION GUIDE

Part Number Output Configuration

Operational

Frequency

(kHz)

Operating Ambient

Temperature Range

TA, (°C)

Packing*

ATS605LSGTN-S-T Speed (OUTA); Speed (OUTB) 20

–40 to 150 800 pieces per 13-in. reel

ATS605LSGTN-S-H-T Speed (OUTA); Speed (OUTB) 40

ATS605LSGTN-F-T Direction (OUTA); XOR Speed (OUTB) 20

ATS605LSGTN-F-H-T Direction (OUTA); XOR Speed (OUTB) 40

ATS605LSGTN-R-T Inverse Direction (OUTA);

XOR Speed (OUTB) 20

ATS605LSGTN-R-H-T Inverse Direction (OUTA);

XOR Speed (OUTB) 40

* Contact Allegro™ for additional packing options.

Pinout Diagram Terminal List Table

Number Name Descritpion

1 VCC Supply voltage

2 OUTB

Option [-S]: Speed (OUTB)

Option [-F]: XOR Speed

Option [-R]: XOR Speed

3 OUTA

Option [-S]: Speed (OUTA)

Option [-F]: Default Direction

Option [-R]: Inverse Direction

4 GND Ground

Branded

Face

1234

Dual Output Differential Speed and Direction Sensor IC

ATS605LSG

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

OPERATING CHARACTERISTICS: Over operating voltage and temperature range, unless otherwise noted

Characteristic Symbol Test Conditions Min. Typ. [1] Max. Unit

ELECTRICAL CHARACTERISTICS

Supply Voltage VCC Operating, TJ < TJ(max) 4.0 – 24 V

Reverse Supply Voltage VRCC –18 – – V

Under Voltage Lockout VCC(UV) VCC from 0 → 5 V or 5 → 0 V – – 3.95 V

Reverse Supply Current IRCC VCC = –18 V – – –10 mA

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

Supply Current ICC

Output OFF (VOUT = High) – 8.5 13 mA

Output ON (VOUT = Low) – 8.5 13 mA

POWER-ON STATE CHARACTERISTCS

Power-On State POS VOUTA, VOUTB, as connected in Figure 7 – High –

Power On Time [2][3] tPO fOP < 200 Hz – – 2 ms

OUTPUT STAGE FOR EACH OUTPUT PIN

Low Output Voltage VOUT(SAT) IOUT = 10 mA, Output = ON – 165 350 mV

Output Zener Clamp Voltage VZoutput IOUT = 3 mA, TA = 25 °C 28 – – V

Output Current Limit IOUT(LIM)

Output = ON (VOUT = Low), measured with

RPULLUP = 0 Ω, TJ < TJ(MAX)

30 55 85 mA

Output Leakage Current IOUT(OFF) Output = OFF, VOUT = 24 V – – 10 μA

Output Rise Time tr

10% - 90%, VPU = 12V, RPULLUP = 1 kΩ,

CL = 4.7 nF – 10 – μs

Output Fall Time tf

90% - 10%, VPU = 12V, RPULLUP = 1 kΩ,

CL = 4.7 nF – 0.6 – μs

DAC CHARACTERISTICS

Allowable User-Induced Magnetic

Offset [4][5] BDIFFEXT User induced differential offset –60 – 60 G

SWITCHPOINT CHARACTERISTICS

Minimum Operational Frequency fOPmin Allegro reference target 0 – – kHz

Maximum Operational Frequency fOPmax

Allegro reference target – 20 – kHz

Allegro reference target, double-bandwidth

option, suffix “-H” – 40 – kHz

Analog Signal Bandwidth f-3dB

Cutoff frequency for low-pass filter – 20 – kHz

Cutoff frequency for low-pass filter, double-

bandwidth option – 40 – kHz

Operate Point BOP % of VPROC(PKPK), Output OFF to ON – 70 – %

Release Point BRP % of VPROC(PKPK), Output ON to OFF – 30 – %

Lockout Enable VLOE VPROC(PKPK) < VLOE = Output Switching Disabled – 250 – mV

Lockout Release VLOR VPROC(PKPK) > VLOE = Output Switching Enabled – 350 – mV

Continued on the next page…

[1] Typical data is at VCC = 12 V and TA = +25°C. Performance may vary for individual units, within the specified maximum and minimum limits.

[2] Power-On Time is the time required to complete the internal automatic offset adjust; the registers are then ready for peak acquisition.

[3] High speed power-on compliant, however several missing output transitions are possible.

[4] 1 G (gauss) = 0.1 mT (millitesla).

[5] The device compensates for magnetic and installation offsets. Offsets greater than specification in gauss may cause inaccuracies in the output.

Dual Output Differential Speed and Direction Sensor IC

ATS605LSG

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

CALIBRATION

First Output Edge – fOP < 600 Hz, VCC > VCC(MIN) – 1 – tooth

Initial Calibration [8] CALI– 3 8 edge

OPERATING CHARACTERISTICS (with Allegro 60-0 reference target)

Operational Air Gap Range [9] AG 0.75 – 3 mm

Direction Output Delay td

Delay between first XOR SPEED output

transition and reported direction change – 400 – ns

Maximum Sudden Air Gap Change /

Signal Reduction [10] ΔBIN

Differential magnetic signal reduction due to

instantaneous air gap change; symmetrical

signal reduction,

fOP < 500 Hz, VPROC(PKPK) > VLOE after sudden

air gap change

– 40 – % pk-pk

Duty Cycle Variation ΔD Valid for SPEED(OUTA) and SPEED(OUTB) 40 50 60 %

Minimum Operating Signal [11] BIN

fOP < 10 kHz – 30 – G

10 kHz ≤ fOP ≤ 20 kHz – 60 – G

fOP < 10 kHz

Double-bandwidth option, suffix “-H” – 30 – G

10 kHz ≤ fOP ≤ 20 kHz

Double-bandwidth option, suffix “-H” – 45 – G

20 kHz < fOP

Double-bandwidth option, suffix “-H” – 60 – G

OPERATING CHARACTERISTICS (continued): Valid throughout full operating and temperature ranges; using Reference Target

60-0; unless otherwise specified

Characteristic Symbol Test Conditions Min. Typ. [7] Max. Unit

[7] Typical data is at VCC = 12 V and TA = +25°C. Performance may vary for individual units, within the specified maximum and minimum limits.

[8] Possible reduced edge accuracy, ΔD not guaranteed. Edges are sensed target mechanical edges (see Definitions of Terms for Switch Points).

[9] Operating air gap is dependent on the available magnetic field. The available field is target geometry and material dependent and should be independently characterized.

[10] Maximum single outward sudden allowable air gap change is in outward direction (increase in air gap).

[11] Output switching (no missed edges). Minimum operating signal, for either operating frequency range, is the differential magnetic field.

Dual Output Differential Speed and Direction Sensor IC

ATS605LSG

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

Figure 1: (a) Sensed Edge: leading (rising) mechanical edge in forward rotation, trailing (falling) mechanical edge in reverse rotation;

(b) BOP(FWD) triggers the output transition during forward rotation, and BOP(REV) triggers the output transition during reverse rotation.

DEFINITIONS OF TERMS FOR SWITCH POINTS

Differential Magnetic

Flux Density, BDIFF (G)

ValleyTooth

Forward

Reverse

–B

Differential Processed

Signal, VProc (V)

–V

BOP(FWD)

VPROC(BOP)

VPROC(BRP)

BRP(FWD)

BOP %BRP %

100 %

BOP(REV)

BRP(REV)

Sensed Edgea

aSensed Edge: leading (rising) mechanical edge in forward rotation, trailing (falling) mechanical edge in reverse rotation

BOP(FWD) triggers the output transition during forward rotation, and BOP(REV) triggers the output transition during reverse rotation

Definitions of Terms for Switchpoints

Dual Output Differential Speed and Direction Sensor IC

ATS605LSG

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

REFERENCE TARGET CHARACTERISTICS 60-0 (60 Tooth Target)

Characteristics Symbol Test Conditions Typ. Unit Symbol Key

Outside Diameter DO

Outside Diameter of

Target 120 mm

Face Width F Breadth of tooth, with

respect to sensor IC 6 mm

Circular Tooth Length t

Length of tooth, with

respect to sensor IC;

measured at DO

3 deg

Circular Valley Width tv

Length of valley, with

respect to sensor IC;

measured at DO

3 deg

Tooth Whole Depth ht3 mm

Material Low Carbon Steel – –

Air Gap

Branded Face

of Package

Figure 2: Example of Allegro Reference Gear

Dual Output Differential Speed and Direction Sensor IC

ATS605LSG

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

FUNCTIONAL DESCRIPTION

Sensing Technology

The ATS605 module contains a single-chip, dual differential

Hall-effect sensor IC, a rare earth pellet, and a flat ferrous pole

piece (concentrator). As shown in Figure 4, the Hall IC supports

three Hall elements, which sense the magnetic profile of the

ferrous gear target simultaneously, but at different points (each

channel spaced at a 1.75 mm pitch), generating two differential

internal analog voltages, VPROC, that is processed for precise

switching of the digital output signals.

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

ture compensated amplifier 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 amplifier 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 During Operation

An operating device is capable of providing digital information

that is representative of the mechanical features of a rotating gear.

The waveform diagram in Figure 4 presents the automatic trans-

lation of the mechanical profile, through the magnetic profile that

it induces, to the digital output signal of the ATS605. No addi-

tional optimization is needed and minimal processing circuitry is

required. This ease of use reduces design time and incremental

assembly costs for most applications.

Operating Modes:

Calibration

Once the power-on time has elapsed, the sensor IC internally

detects the magnetic profile of the target. The output becomes

active at the first detected switchpoint.

The gain of the sensor IC is adjusted during the Calibration

period, normalizing the internal signal amplitude for the air gap

range of the device. This Automatic Gain Control (AGC) feature

ensures that operational characteristics are isolated from the

effects of installation air gap variation.

Automatic Offset Adjustment (AOA) is circuitry that compen-

sates for the effects of chip, magnet, and installation offsets. (For

capability, see Allowable User-Induced Magnetic Offset, in the

Operating Characteristics table.) This circuitry works with the

AGC during calibration to help center VPROC in the dynamic

range to allow for DAC acquisition of signal peaks.

Calibration also allows for the peak detecting DACs to properly

acquire the magnetic signal, so that Running Mode switch points

can be accurately computed.

Running Mode

After calibration is complete, direction information is available.

This information is communicated through the available output

option.

Peak-tracking DAC algorithms allow tracking of signal drift over

temperature changes, as well as tracking of target variations, such

as tooth-to-tooth variation and effective runout. The sensor’s

dynamic monitoring of these signal peaks is updated on each

tooth and valley edge.

Automatic Offset Adjust remains active, allowing the IC to com-

pensate for offsets induced by temperature variations over time.

Figure 3: Target Rotation for Default Sensing Configuration.

(A) Pin 4 to pin 1 is forward, and (B) pin 1 to pin 4 is reverse.

Dual Output Differential Speed and Direction Sensor IC

ATS605LSG

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

Output

The device provides three outputs (DIRECTION, XOR SPEED,

and SPEED), available in two combinations: Option #1 (-S) is

SPEED (Ch. A) and SPEED (Ch. B), and Option #2 (-F) is XOR

SPEED and DIRECTION. DIRECTION provides the target

rotation direction relative to the device. XOR SPEED provides

an XOR’d output of the two speed channels (Ch. A and Ch. B),

which results in double the speed data rate without requiring

changes to be made to the controller. SPEED will be updated

before DIRECTION and is updated at every transition of both

Channel A and Channel B allowing the use of up-down counters

without the loss of pulses.

Output Polarity

In Figure 4, the top panel, labeled Mechanical Position, repre-

sents the mechanical features of the target gear and orientation

to the device. The bottom panel, labeled Output Option # 1, the

–S variant, displays the square waveforms corresponding to the

digital SPEED output signals for channels A and B for a rotating

gear in the forward rotation direction (gear tooth passing from the

pin 4 side to the pin 1 side, Figure 3). The end result is the sensor

output switching from high state to low state as the leading edge

of a tooth (a rising mechanical edge, as detected by the sensor)

passes the sensor face. If the direction of rotation is reversed so

that the gear rotates from the pin 1 side to the pin 4 side (Figure

3), then the output polarity inverts (i.e., the output signal goes

high when a rising edge is detected, and a tooth is the nearest

feature to the sensor).

The Output Option #2 panel refers to the –F variant, for which

DIRECTION polarity is defined as ON (low) when the target

crosses the sensor face in the forward direction (from the pin

4 side to the pin 1 side), and OFF (high) for the reverse direc-

tion (from the pin 1 side to the pin 4 side). There is an option,

ATS605LSGTN-R-T, that inverts this DIRECTION output signal

polarity (SPEED output polarity is unaffected and remains as

defined above). XOR SPEED polarity is defined as SPEED A

XOR SPEED B.

Table 1: Output Pin Descriptions

Option Pin 2 / OUTB Pin 3 / OUTA

Option 1 (“-S”) SPEED B SPEED A

Option 2 (“-F”) XOR SPEED DIRECTION

Option 2 (“-R”) XOR SPEED Inverted DIRECTION

Figure 4: The magnetic profile reflects the geometry of the

target, allowing the ATS605 to present an accurate digital output

response. Please see Figure 5 for more detailed output switching.

Dual Output Differential Speed and Direction Sensor IC

ATS605LSG

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

Figure 5: Direction change, first showing the default forward rotation output polarity and then for the same output configuration, the

reverse direction polarity is shown (Pin 4 to Pin 1 is FWD).

Channel A

Channel B

OUTA:

OUTB:

CHA

CHB

Dual Output Differential Speed and Direction Sensor IC

ATS605LSG

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

Undervoltage Lockout

When the supply voltage falls below the undervoltage lockout

voltage, UVLO, the device enters Reset, where the output state

returns to the Power-On State (POS) until sufficient VCC is

supplied. ICC levels may not meet datasheet limits when VCC <

VCC(min). This lockout feature prevents false signals, caused by

undervoltage conditions, from propagating to the output of the

sensor.

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 unregu-

lated power supply, transient protection must be added externally.

For applications using a regulated line, EMI/RFI protection may

still be required. Contact Allegro MicroSystems for information

on the circuitry needed for compliance with various EMC speci-

fications. Refer to Figure 7 for an example of a basic application

circuit.

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-

fication). At power-on, the device determines the peak-to-peak

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

sensor is then automatically adjusted. Figure 6 illustrates the

effect of this feature.

DEVICE FEATURES

Automatic Offset Adjust (AOA)

The AOA circuitry automatically compensates for the effects of

chip, magnet, and installation offsets. (For capability, see Allow-

able User-Induced Magnetic Offset, in the Operating Character-

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

during power-on mode and running mode, compensating for any

offset drift (within Allowable User-Induced Magnetic Offset).

Continuous operation also allows it to compensate for offsets

induced by temperature variations over time.

Lockout

The ATS605 has a lockout feature to prevent switching on small

signals that are characteristic of vibration signals. The internal

logic of the chip will consider small signal amplitudes below a

certain level to be vibration. The output will then be held to the

state prior to lockout until the amplitude of the signal returns to

normal operational levels. Lockout is independent between speed

channels for the SPEED and SPEED output configuration, allow-

ing one channel to continue switching without the other. The

alternative XOR SPEED and DIRECTION configuration requires

both channels to exceed the lockout release value before enabling

these output signals.

Assembly Description

The ATS605 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 6: Automatic Gain Control (AGC). The AGC function corrects for

variances in the air gap. Differences in the air gap cause differences in

the magnetic field at the device, but AGC prevents that from affecting

device performance, as shown in the lower panel.

ATS605

GND

0.1 µF

PULLUP(A)

PULLUP(B)

BYP

OUTB

LOAD(A)

LOAD(B)

2OUTA

Figure 7: Typical Application Circuit

Dual Output Differential Speed and Direction Sensor IC

ATS605LSG

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

Start Mode Hysteresis

This feature helps to ensure optimal self-calibration by reject-

ing electrical noise and low-amplitude target vibration during

initialization. This prevents AGC from calibrating the IC on such

spurious signals. Calibration can be performed using the actual

target features.

A typical scenario is shown in Figure 8. The Start Mode Hyster-

esis, POHYS, is a minimum level of the peak-to-peak amplitude

of the internal analog electrical signal, VPROC, that must be

exceeded before the ATS605 starts to compute switch points.

Figure 8: Operation of Start Mode Hysteresis

• At power-on (position 1), the ATS605 begins sampling VPROC.

• At the point where the Start Mode Hysteresis, POHYS, is exceeded, the device establishes an initial switching threshold, by using the

Continuous Update algorithm. If VPROC is falling through the limit on the low side (position 2), the switchpoint is BRP, and if VPROC

is rising through the limit on the high side (position 4), it is BOP. After this point, Start Mode Hysteresis is no longer a consider-

ation. Note that a valid VPROC value exceeding the Start Mode Hysteresis can be generated either by a legitimate target feature or by

excessive vibration.

• In either case, because the switchpoint is immediately passed as soon as it is established, the ATS605 enables switching:

--If on the low side, at BRP (position 2) the output would switch from low to high. However, because output is already high, no

output switching occurs.

At the next switchpoint, where BOP is passed (position 3), the output switches from high to low.

--If on the high side, at BOP (position 4) the output switches from high to low.

As this example demonstrates, initial output switching occurs with the same polarity, regardless of whether the Start Mode Hysteresis

is exceeded on the high side or on the low side

Dual Output Differential Speed and Direction Sensor IC

ATS605LSG

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

CHARACTERISTIC PERFORMANCE

Dual Output Differential Speed and Direction Sensor IC

ATS605LSG

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

CHARACTERISTIC PERFORMANCE (continued)

Dual Output Differential Speed and Direction Sensor IC

ATS605LSG

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

THERMAL CHARACTERISTICS

Characteristic Symbol Test Conditions Value Unit

Package Thermal Resistance RqJA

Minimum-K PCB, single-layer, single-sided, with copper limited to

solder pads) 126 °C/W

Low-K PCB, single-layer, single-sided with copper limited to solder

pads and 3.57 in.2 (23.03 cm2) of copper area each side 84 °C/W

VCC(max)

VCC(min)

Dual Output Differential Speed and Direction Sensor IC

ATS605LSG

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

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 supplied

power or improving the heat dissipation properties of the appli-

cation. This section presents a procedure for correlating factors

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

Allegro MicroSystems website.)

The Package Thermal Resistance, RθJA, is a figure 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, RθJC, is relatively

small component of RθJA. Ambient air temperature, TA, and air

motion are significant 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 × RθJA (2)

TJ = TA + ∆T (3)

For example, given common conditions such as:

TA= 25°C, VCC = 12 V, RθJA = 126°C/W, and

ICC = 8.5 mA, then:

PD = VCC × ICC = 12 V × 8.5 mA = 102 mW

∆T = PD × RθJA = 102 mW × 126°C/W = 12.9°C

J = TA + ∆T = 25°C + 12.9°C = 37.9°C

POWER DERATING

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

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

at a selected RθJA and TA.

Example: Reliability for VCC at TA = 150°C, package SG, using

single-layer PCB.

Observe the worst-case ratings for the device, specifically:

RθJA = 126°C/W, TJ(max) = 165°C, VCC(max) = 24 V, and

ICC = 13 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 ÷ RθJA = 15°C ÷ 126°C/W = 119 mW

Finally, invert equation 1 with respect to voltage:

VCC(est) = PD(max) ÷ ICC(max) = 119 mW ÷ 13 mA = 9.2 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

RθJA. If VCC(est) ≥ VCC(max), then operation between VCC(est) and

VCC(max) is reliable under these conditions.

Dual Output Differential Speed and Direction Sensor IC

ATS605LSG

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

Package SG, 4-Pin SIP

0.71 ±0.05

5.50 ±0.05

4.70 ±0.10

0.60 ±0.10

0.40 ±0.10

24.65 ±0.10

15.30 ±0.10

1.0 REF

0.71 ±0.100.71 ±0.10

1.60 ±0.10

1.27 ±0.10

5.50 ±0.10

8.00 ±0.05

5.80 ±0.05

1.70 ±0.10

243

1.75 1.75

For Reference Only, not for tooling use (reference DWG-9200)

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

Hall elements (E1, E2, E3), not to scale

= Supplier emblem

= Lot identiﬁer

= Last three numbers of device part number

= Last two digits of year of manufacture

= Week of manufacture

Standard Branding Reference View

LLLLLLL

NNN

YYWW

Branded

Face

Branding scale and appearance at supplier discretion

0.38 +0.06

–0.04

Dual Output Differential Speed and Direction Sensor IC

ATS605LSG

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

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

www.allegromicro.com

Allegro MicroSystems reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit

improvements in the performance, 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 any devices or systems, including but not limited to life support devices or systems, in which a failure of

Allegro’s product can reasonably be expected to cause bodily harm.

The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems assumes no responsibility for its use; nor

for any infringement of patents or other rights of third parties which may result from its use.

Copies of this document are considered uncontrolled documents.

Revision History

Number Date Description

– March 28, 2014 Initial release

1 December 5, 2016 Updated Functional Block Diagram (page 1) and Minimum Operating Signal (page 4)

2 June 15, 2017 Corrected typo in symbol for Output Fall Time (page 3)

3 June 20, 2018 Minor editorial updates

4 July 3, 2019 Minor editorial updates