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 switchpoints
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-basing magnet with a 100% matte-
tin-plated leadframe.
ATS605LSG-DS, Rev. 3
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 switchpoints
• 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
June 20, 2018
Hall Amp
VCC
REGULATOR
(Analog)
REGULATOR
(Digital)
OFFSET
ADJUST
OFFSET
ADJUST
AGC
AGC
FILTER
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
2
Allegro MicroSystems, LLC
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
Operating Ambient
Temperature Range
TA, (°C)
Output Configuration
Operational
Frequency
(kHz)
Packing*
ATS605LSGTN-S-T –40 to 150 Speed (OUTA); Speed (OUTB) 20 800 pieces per 13-in. reel
ATS605LSGTN-S-H-T –40 to 150 Speed (OUTA); Speed (OUTB) 40 800 pieces per 13-in. reel
ATS605LSGTN-F-T –40 to 150 Direction (OUTA); XOR Speed (OUTB) 20 800 pieces per 13-in. reel
ATS605LSGTN-F-H-T –40 to 150 Direction (OUTA); XOR Speed (OUTB) 40 800 pieces per 13-in. reel
ATS605LSGTN-R-T –40 to 150 Inverse Direction (OUTA);
XOR Speed (OUTB) 20 800 pieces per 13-in. reel
ATS605LSGTN-R-H-T –40 to 150 Inverse Direction (OUTA);
XOR Speed (OUTB) 40 800 pieces per 13-in. reel
* 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
3
Allegro MicroSystems, LLC
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
4
Allegro MicroSystems, LLC
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 Switchpoints).
[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
5
Allegro MicroSystems, LLC
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 SWITCHPOINTS
Differential Magnetic
Flux Density, BDIFF (G)
ValleyTooth
Forward
Reverse
+B
–B
Differential Processed
Signal, VProc (V)
+V
–V
t
BOP(FWD)
b
VPROC(BOP)
VPROC(BRP)
BRP(FWD)
BOP %BRP %
100 %
BOP(REV)
b
BRP(REV)
Sensed Edgea
aSensed 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 Switchpoints
Dual Output Differential
Speed and Direction Sensor IC
ATS605LSG
6
Allegro MicroSystems, LLC
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 – –
F
h
t
Do
tv
t
Air Gap
Branded Face
of Package
Figure 2: Example of Allegro Reference Gear
Dual Output Differential
Speed and Direction Sensor IC
ATS605LSG
7
Allegro MicroSystems, LLC
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 switchpoints
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
8
Allegro MicroSystems, LLC
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
9
Allegro MicroSystems, LLC
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).
B
B
Channel A
Channel B
OUTA:
OUTB:
CHA
CHB
Dual Output Differential
Speed and Direction Sensor IC
ATS605LSG
10
Allegro MicroSystems, LLC
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.
V
R
R
R
C
V
C
C
ATS605
GND
0.1 µF
V
CC
S
PULLUP(A)
PULLUP(B)
BYP
OUTB
LOAD(A)
LOAD(B)
1
3
4
2OUTA
Figure 7: Typical Application Circuit
Dual Output Differential
Speed and Direction Sensor IC
ATS605LSG
11
Allegro MicroSystems, LLC
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 switchpoints.
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
12
Allegro MicroSystems, LLC
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
CHARACTERISTIC PERFORMANCE
Dual Output Differential
Speed and Direction Sensor IC
ATS605LSG
13
Allegro MicroSystems, LLC
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
14
Allegro MicroSystems, LLC
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
15
Allegro MicroSystems, LLC
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
T
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
16
Allegro MicroSystems, LLC
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
A
A
A
B
B
C
C
D
D
E
E
FF
F
F
FF
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
L
N
Y
W
Standard Branding Reference View
LLLLLLL
NNN
YYWW
Branded
Face
E1
E2
E3
Branding scale and appearance at supplier discretion
0.38 +0.06
–0.04
Dual Output Differential
Speed and Direction Sensor IC
ATS605LSG
17
Allegro MicroSystems, LLC
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
For the latest version of this document, visit our website:
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Copyright ©2018, Allegro MicroSystems, LLC
Allegro MicroSystems, LLC 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, LLC 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
