Description
The ATS616 gear-tooth sensor IC is a peak-detecting device
that uses automatic gain control and an integrated capacitor
to provide extremely accurate gear edge detection down to
low operating speeds. Each package consists of a high-tem-
perature plastic shell that holds together a samarium-cobalt
pellet, a pole piece, and a differential open-collector Hall IC
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.
The technology used for this circuit is Hall-effect based.
The chip incorporates a dual-element Hall IC that switches
in response to differential magnetic signals created by fer-
romagnetic targets. The sophisticated processing circuitry
contains an A-to-D converter that self-calibrates (normal-
izes) the internal gain of the device to minimize the effect of
air-gap variations. The patented peak-detecting filter circuit
eliminates magnet and system offsets and has the ability to
discriminate relatively fast changes such as those caused by
tilt, gear wobble, and eccentricities. This easy-to-integrate
solution provides first-tooth detection and stable operation
to extremely low rpm. The ATS616 can be used as a replace-
ment for the ATS612LSB, eliminating the external peak-
holding capacitor needed by the ATS612LSB.
ATS616LSG-DS, Rev. 4
Features and Benefits
• Self-calibrating for tight timing accuracy
• First-tooth detection
• Immunity to air gap variation and system offsets
• Eliminates effects of signature tooth offsets
• Integrated capacitor provides analog peak and valley
information
• Extremely low timing-accuracy drift with temperature
changes
• Large air gap capability
• Small, integrated package
• Optimized magnetic circuit
• Undervoltage lockout (UVLO)
• Wide operating voltage range
Dynamic Self-Calibrating Peak-Detecting Dif ferential
Hall Ef fect Gear Tooth Sensor IC
Package: 4-pin SIP (suffix SG)
Functional Block Diagram
Not to scale
ATS616LSG
Continued on the next page…
GND
VOUT
VCC
Voltage
Regulator
TEST
Hall
Amp
Reference
Generator
Gain
Current
Limit
(Recommended)
Hall
Amp Track and
Hold
Track and
Hold
UVLO Power-On
Logic
Tooth and Valley
Comparator
Dynamic Self-Calibrating Peak-Detecting Dif ferential
Hall Ef fect Gear Tooth Sensor IC
ATS616LSG
2
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Pin-out Diagram
Absolute Maximum Ratings
Characteristic Symbol Notes Rating Unit
Supply Voltage VCC See Power Derating section 26.5 V
Reverse-Supply Voltage VRCC –18 V
Output Off Voltage VOUTOFF 24 V
Continuous Output Current IOUT 25 mA
Reverse-Output Current IROUT 50 mA
Operating Ambient Temperature TAL temperature range –40 to 150 ºC
Maximum Junction Temperature TJ(max) 165 ºC
Storage Temperature Tstg –65 to 170 ºC
Terminal List Table
Number Name
1 VCC
2 VOUT
3 Test Pin (tie to GND)
4 GND
Selection Guide
Part Number Package Packing*
ATS616LSGTN-T 4-pin plastic SIP 800 pieces per 13-in. reel
*Contact Allegro™ for additional packing options
The ATS616 is ideal for use in systems that gather speed, posi-
tion, and timing information using gear-tooth-based configura-
tions. This device is particularly suited to those applications that
require extremely accurate duty cycle control or accurate edge-
detection, such as automotive camshaft sensing.
TheATS616 is provided in a 4-pin SIP that is Pb (lead) free, with
a 100% matte tin plated leadframe.
Description (continued)
2431
Dynamic Self-Calibrating Peak-Detecting Dif ferential
Hall Ef fect Gear Tooth Sensor IC
ATS616LSG
3
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
OPERATING CHARACTERISTICS over operating voltage and temperature range, unless otherwise noted
Characteristic Symbol Test Condition Min. Typ.1Max. Units
ELECTRICAL CHARACTERISTICS
Supply Voltage2VCC Operating, TJ < 165C 3.5 – 24 V
Power-On State POS VCC = 0 → 5 V – HIGH – V
Undervoltage Lockout Threshold VCC(UV) VCC = 0 → 5 V; VCC = 5 → 0 V – – 3.5 V
Output On Voltage VOUT(SAT) IOUT = 20 mA – 200 400 mV
Supply Zener Clamp Voltage VZsupply ICC = 16 mA, TA = 25°C 28 – – V
Output Zener Clamp Voltage VZoutput IOUT = 3 mA, TA = 25°C 30 – – V
Supply Zener Current IZsupply VS = 28 V – – 15 mA
Output Zener Current IZoutput VOUT = 30 V – – 3 mA
Output Current Limit IOUTM VOUT = 12 V 25 45 55 mA
Output Leakage Current IOUTOFF VOUT = 24 V – – 15 μA
Supply Current ICC VCC > VCC(min) 3 6 12 mA
Power-On Time tPO VCC > 5 V – 80 500 μs
Output Rise Time3trRLOAD = 500 Ω, CS = 10 pF – 0.3 5.0 μs
Output Fall Time3tfRLOAD = 500 Ω, CS = 10 pF – 0.2 5.0 μs
PERFORMANCE CHARACTERISTICS
Operating Air Gap Range AG Operating within specification, Target Speed > 10 rpm 0.4 – 2.5 mm
Operating Magnetic Flux Density
Differential4BAG(p-p) Operating within specification, Target Speed > 10 rpm 60 – – G
Operating Frequency ƒ 10 – 10 000 Hz
Initial Calibration Cycle5ncal Output edges before calibration is completed, at fsig < 100 Hz 1 1 1 Edge
Calibration Mode Disable ndis Output falling edges for startup calibration to be complete 64 64 64 Edge
Relative Timing Accuracy, Sequential Eθ
Target Speed = 1000 rpm, BAG(p-p) > 100 G – ±0.5 ±0.75
Target Speed = 1000 rpm, BAG(p-p) > 60 G – – ±1.5
Allowable User Induced Differential Offset4∆BApp
Output switching only; may not meet data sheet specifica-
tions – – ±50 G
1Typical data is at VCC = 8 V and TA = 25°C. 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 Power Derating section.
3 CS is the probe capacitance of the oscilloscope used to make the measurement.
4 10 G = 1 mT (millitesla), exactly.
5Non-uniform magnetic profiles may require additional edges before calibration is complete.
Dynamic Self-Calibrating Peak-Detecting Dif ferential
Hall Ef fect Gear Tooth Sensor IC
ATS616LSG
4
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
REFERENCE TARGET 60+2
Characteristics Symbol Test Conditions Typ. Unit Symbol Key
Outside Diameter DoOutside diameter of target 120 mm
t,t
SIG
tV
ØD
O
h
t
F
Branded Face
of Package
Air Gap
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
Signature Region Cir-
cular Tooth Length tSIG
Length of signature tooth,
with respect to branded face;
measured at Do
15 mm
Circular Valley Length tv
Length of valley, with respect
to branded face; measured
at Do
3mm
Tooth Whole Depth ht3mm
––leetS nobraC woLlairetaM
Reference Target
Signature Region
60+2
of Package
Branded Face
Pin 4
Pin 1
Reference Target (Gear) Information
For the generation of adequate magnetic field levels, the fol-
lowing recommendations should be followed in the design and
specification of targets:
• 2 mm < tooth width, t < 4 mm
• Valley width, tv > 2 mm
• Valley depth, ht > 2 mm
• Tooth thickness, F ≥ 3 mm
• Target material must be low carbon steel
Although these parameters apply to targets of traditional
geometry (radially oriented teeth with radial sensing, shown in
figure 1), they also can be applied in applications using stamped
targets (an aperture or rim gap punched out of the target mate-
rial) and axial sensing. For stamped geometries with axial sens-
ing, the valley depth, ht, is intrinsically infinite, so the criteria for
tooth width, t, valley width, tv, tooth material thickness, F, and
material specification need only be considered for reference. For
example, F can now be < 3 mm.
Figure 1. Configuration with Radial-Tooth Reference Target
Dynamic Self-Calibrating Peak-Detecting Dif ferential
Hall Ef fect Gear Tooth Sensor IC
ATS616LSG
5
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Characteristic Data
Continued on the next page.
VCC (V)
Supply Current (Off) versus Supply Voltage
T
A
(°C)
ICCOFF (mA)
TA (°C)
Supply Current (Off) versus Ambient Temperature
ICCOFF (mA)
Output Voltage (On) versus Ambient Temperature
I
SINK
(mA)
VOUT(SAT) (mV)
20
V
OUT
(V)
10
Supply Current (On) versus Ambient Temperature
ICCON (mA)
Output Leakage Current versus Ambient Temperature
IOUTOFF (µA)
25
85
150
–40
VCC (V)
Supply Current (On) versus Supply Voltage
ICCON (mA)
V
CC
(V)
3.5
5.0
12
24
TA (°C)
TA (°C) TA (°C)
VCC (V)
T
A
(°C)
25
85
150
–40
V
CC
(V)
3.5
5.0
12
24
0
1
2
3
4
5
7
6
9
8
0
1
2
3
4
5
7
6
9
8
0
1
2
3
4
5
7
6
9
8
010201552530
0
1
2
3
4
5
7
6
9
8
010201552530
–50 0 50 100 150 200
0
50
100
150
200
250
300
350
–50 0 50 100 150 200
–50 0 50 100 150 200 –50 0 50 100 150 200
0
0.2
0.4
0.6
0.8
1.0
1.2
Dynamic Self-Calibrating Peak-Detecting Dif ferential
Hall Ef fect Gear Tooth Sensor IC
ATS616LSG
6
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Characteristic Data (continued)
Relative Timing Accuracy versus Air Gap
Edge Position (°)
Edge Position (°)
Edge Position (°)
TA (°C)
–40
0
25
85
125
150
TA (°C)
–40
0
25
85
125
150
TA (°C)
–40
0
25
85
125
150
Signature Tooth Rising Edge
1000 rpm
AG (mm)
Edge Position (°)
AG (mm)
AG (mm)
Relative Timing Accuracy versus Air Gap Relative Timing Accuracy versus Air Gap
Sequential Tooth Falling Edge
1000 rpm
Signature Tooth Falling Edge
1000 rpm
Relative Timing Accuracy versus Air Gap
Sequential
Tooth Rising Edge
1000 rpm
AG (mm)
TA (°C)
–40
0
25
85
125
150
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
03.02.52.01.51.00.5
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
03.02.52.01.51.00.5
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
03.02.52.01.51.00.5
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
03.02.52.01.51.00.5
Dynamic Self-Calibrating Peak-Detecting Dif ferential
Hall Ef fect Gear Tooth Sensor IC
ATS616LSG
7
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Characteristic Data (continued)
Relative Timing Accuracy versus Ambient Temperature
Edge Position (°)
Edge Position (°)
Edge Position (°)
rpm
rpm rpm
Signature Tooth Rising Edge
0.5 mm
T
A
(°C)
Edge Position (°)
T
A
(°C)
T
A
(°C)
Relative Timing Accuracy versus Ambient Temperature Relative Timing Accuracy versus Ambient Temperature
Sequential Tooth Falling Edge
0.5 mm
Sequential Tooth Rising Edge
0.5 mm
Relative Timing Accuracy versus Ambient Temperature
Signature
Tooth Falling Edge
0.5 mm
T
A
(°C)
rpm
10
100
500
1000
1500
2000
10
100
500
1000
1500
2000
10
100
500
1000
1500
2000
10
100
500
1000
1500
2000
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
–50 200150100500
–50 200150100500
–50 200150100500
–50 200150100500
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
Dynamic Self-Calibrating Peak-Detecting Dif ferential
Hall Ef fect Gear Tooth Sensor IC
ATS616LSG
8
Allegro MicroSystems, LLC
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-sided PCB with copper limited to solder pads 126 ºC/W
Two-sided PCB with copper limited to solder pads and 3.57 in.2
(23.03 cm2) of copper area each side, connected to GND pin 84 ºC/W
*Additional information is available on the Allegro Web site.
6
7
8
9
2
3
4
5
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
20 40 60 80 100 120 140 160 180
Temperature (ºC)
Maximum Allowable V
CC
(V)
TJ(max) = 165ºC; ICC = ICC(max)
Power Derating Curve
(R
θJA
= 126 ºC/W)
(R
θJA
= 84 ºC/W)
VCC(min)
VCC(max)
0
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
D
(mW)
TJ(max) = 165ºC; VCC = VCC(max); ICC = ICC(max)
Maximum Power Dissipation, PD(max)
(R
θJA
= 126 ºC/W)
(RθJA = 84 ºC/W)
Dynamic Self-Calibrating Peak-Detecting Dif ferential
Hall Ef fect Gear Tooth Sensor IC
ATS616LSG
9
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Assembly Description. The ATS616 is a Hall IC/rare earth
pellet configuration that is fully optimized to provide digi-
tal response to gear tooth edges. This device is packaged in a
molded miniature plastic body that has been optimized for size,
ease of assembly, and manufacturability. High operating tem-
perature materials are used in all aspects of construction.
After proper power is applied to the component, the IC is
capable of instantly providing digital information that is repre-
sentative of the profile of a rotating gear. No additional optimi-
zation or processing circuitry is required. This ease of use should
reduce design time and incremental assembly costs for most
applications.
Hall Technology. The package contains a single-chip differential
Hall effect sensor IC, a samarium cobalt pellet, and a flat ferrous
pole piece (figure 2). The Hall IC consists of 2 Hall elements
(spaced 2.2 mm apart) located so as to measure the magnetic
gradient created by the passing of a ferromagnetic object. The
two elements measure the magnetic gradient and convert it to an
analog voltage that is then processed in order to provide a digital
output signal.
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.
Internal Electronics. The processing circuit uses a patented
peak detection scheme to eliminate magnet and system offsets.
This technique allows dynamic coupling and filtering of offsets
without the power-up and settling time disadvantages of classical
high-pass filtering schemes. The peak signal of every tooth and
valley is detected by the filter and is used to provide an instant
reference for the operate and release point comparator. In this
manner, the thresholds are adapted and referenced to individual
signal peaks and valleys, providing immunity to zero line varia-
tion from installation inaccuracies (tilt, rotation, and off-center
placement), as well as for variations caused by target and shaft
eccentricities. The peak detection concept also allows extremely
low speed operation for small value filter capacitors.
The ATS616 also includes self-calibration circuitry that is
engaged at power on. The signal amplitude is measured, and
then the device gain is normalized. In this manner switchpoint
drift versus air gap is minimized, and excellent timing accuracy
can be achieved.
The AGC (Automatic Gain Control) circuitry, in conjunction
with a unique hysteresis circuit, also eliminates the effect of
gear edge overshoot as well as increases the immunity to false
switching caused by gear tooth anomalies at close air gaps. The
Functional Description
Target (Gear)
Back-biasing
rare-earth pellet
South Pole
North Pole Case
(Pin 1 Side)(Pin n >1 Side)
Hall IC
Pole Piece
Element Pitch
(Concentrator)
Dual-Element
Hall Effect Device
Hall Element 1
Hall Element 2
Figure 2. Relative motion of the target is detected by the dual Hall ele-
ments mounted on the Hall IC.
Figure 3. The peaks in the resulting differential signal are used to set the
operate, BOP
, and release, BRP
, switchpoints.
Device Output
V
OUT
B
RP
Differential
Magnetic Flux
B+
B–
0
V
CC
V
OUT(sat)
B
OP
B
RP
B
OP
Dynamic Self-Calibrating Peak-Detecting Dif ferential
Hall Ef fect Gear Tooth Sensor IC
ATS616LSG
10
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
AGC circuit sets the gain of the device after power-on. Up to a
0.25 mm air gap change can occur after calibration is complete
without significant performance impact.
Superior Performance. The ATS616 has several advantages
over conventional Hall-effect devices. The signal-processing
techniques used in the ATS616 solve the catastrophic issues that
affect the functionality of conventional digital gear-tooth sen-
sors, such as the following:
• Temperature drift. Changes in temperature do not greatly
affect this device due to the stable amplifier design and the
offset rejection circuitry.
• Timing accuracy variation due to air gap. The accuracy varia-
tion caused by air gap changes is minimized by the self-cali-
bration circuitry. A 2×-to-3× improvement can be seen.
• Dual edge detection. Because this device switches based on
the positive and negative peaks of the signal, dual edge detec-
tion is guaranteed.
• Tilted or off-center installation. Traditional differential sensor
ICs can switch incorrectly due to baseline changes versus air
gap caused by tilted or off-center installation. The peak detec-
tor circuitry references the switchpoint from the peak and is
immune to this failure mode. There may be a timing accuracy
shift caused by this condition.
• Large operating air gaps. Large operating air gaps are achiev-
able with this device due to the sensitive switchpoints after
power-on (dependent on target dimensions, material, and
speed).
• Immunity to magnetic overshoot. The patented adjustable
hysteresis circuit makes the ATS616 immune to switching on
magnetic overshoot within the specified air gap range.
• Response to surface defects in the target. The gain-adjust
circuitry reduces the effect of minor gear anomalies that would
normally cause false switching.
• Immunity to vibration and backlash. The gain-adjust circuitry
keeps the hysteresis of the device roughly proportional to the
peak-to-peak signal. This allows the device to have good im-
munity to vibration even when operating at close air gaps.
• Immunity to gear run out. The differential chip configuration
eliminates the baseline variations caused by gear run out.
Differential vs. Single-Element Design. The differential chip
configuration is superior in most applications to the classical
single-element design. The single-element configuration com-
monly used (Hall-effect element mounted on the face of a simple
permanent magnet) requires the detection of a small signal (often
<100 G) that is superimposed on a large back-biased field, often
1500 G to 3500 G. For most gear/target configurations, the back-
biased field values change due to concentration effects, resulting
in a varying baseline with air gap, valley widths, eccentricities,
and vibration (figure 4). The differential configuration (figure 5)
cancels the effects of the back-biased field and avoids many of
the issues presented by the single Hall element design.
Peak Detecting vs. AC-Coupled Filters. High-pass filtering
Figure 4. Affect of varying valley widths on single-element circuits.
Figure 4. Affect of varying air gaps on differential circuits.
Dynamic Self-Calibrating Peak-Detecting Dif ferential
Hall Ef fect Gear Tooth Sensor IC
ATS616LSG
11
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
(normal AC coupling) is a commonly used technique for elimi-
nating circuit offsets. However, AC coupling has errors at power-
on because the filter circuit needs to hold the circuit zero value
even though the circuit may power-on over a large signal. Such
filtering techniques can only perform properly after the filter
has been allowed to settle, which typically takes longer than 1s.
Also, high-pass filter solutions cannot easily track rapidly chang-
ing baselines, such as those caused by eccentricities. (The term
baseline refers to a 0 G differential field, where each Hall-effect
element is subject to the same magnetic field strength; see figure
3.) In contrast, peak detecting designs switch at the change in
slope of the differential signal, and so are baseline-independent
both at power-on and while running.
Peak Detecting vs. Zero-Crossing Reference. The usual dif-
ferential zero-crossing sensor ICs are susceptible to false switch-
ing due to off-center and tilted installations that result in a shift
of the baseline that changes with air gap. The track-and-hold
peak detection technique ignores baseline shifts versus air gaps
and provides increased immunity to false switching. In addition,
using track-and-hold peak detection techniques, increased air
gap capabilities can be expected because peak detection utilizes
the entire peak-to-peak signal range, as compared to zero-cross-
ing detectors, which switch at half the peak-to-peak signal.
Power-On Operation. The device powers-on in the Off state
(output voltage high), irrespective of the magnetic field condi-
tion. The power-up time of the circuit is no greater than 500 μs.
The circuit is then ready to accurately detect the first target edge
that results in a high-to-low transition of the device output.
Undervoltage Lockout (UVLO). When the supply voltage, VCC ,
is below the minimum operating voltage, VCC(UV) , the device is
off and stays off, irrespective of the state of the magnetic field.
This prevents false signals, which may be caused by undervolt-
age conditions (especially during power-up), from appearing at
the output.
Output. The device output is an open-collector stage capable of
sinking up to 20 mA. An external pull-up (resistor) must be sup-
plied to a supply voltage of not more than 24 V.
Output Polarity. The output of the unit will switch from low to
high as the leading edge of a tooth passes the branded face of the
package in the direction indicated in figure 6. This means that in
such a configuration, the output voltage will be high when the
package is facing a tooth. If the target rotation is in the oppo-
site direction relative to the package, the output polarity will be
opposite as well, with the unit switching from low to high as the
leading edge passes the unit.
of Package
Rotating Target Branded Face
14
Figure 6. This left-to-right (pin 1 to pin 4) direction of target rotation
results in a high output signal when a tooth of the target gear is nearest
the branded face of the package. A right-to-left (pin 4 to pin 1) rotation
inverts the output signal polarity.
Figure 7. The magnetic profile reflects the geometry of the target, allowing the device to present an accurate digital output response.
Target
Mechanical Profile
Target
Magnetic Profile
IC Output
Electrical Profile
Target Motion from
Pin 1 to Pin 4
IC Output
Electrical Profile
Target Motion from
Pin 4 to Pin 1
Signature Tooth
B+
BIN
V+
VOUT
V+
VOUT
IC Output
Switch State
On Off On Off On Off On Off On OffOn OffOn OffOn Off
Dynamic Self-Calibrating Peak-Detecting Dif ferential
Hall Ef fect Gear Tooth Sensor IC
ATS616LSG
12
Allegro MicroSystems, LLC
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, RJA, 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, RJC, is
relatively small component of RJA. 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 × RJA (2)
TJ = TA + ΔT
(3)
For example, given common conditions such as: TA= 25°C,
VCC = 12 V, ICC = 4 mA, and RJA = 140°C/W, then:
P
D = VCC × ICC = 12 V × 4 mA = 48 mW
T = PD × RJA = 48 mW × 140°C/W = 7°C
T
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 RJA and TA.
Example: Reliability for VCC at TA =
150°C, package SG, using
minimum-K PCB.
Observe the worst-case ratings for the device, specifically:
RJA
=
126°C/W, TJ(max) =
165°C, VCC(max)
=
24 V, and
ICC(max) = 12
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 ÷ RJA = 15°C ÷ 126°C/W = 119 mW
Finally, invert equation 1 with respect to voltage:
VCC(est) = PD(max) ÷ ICC(max) = 119 mW ÷ 12 mA = 9.92 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
RJA. If VCC(est) ≥ VCC(max), then operation between VCC(est) and
VCC(max) is reliable under these conditions.
This value applies only to the voltage drop across the ATS616
chip. If a protective series diode or resistor is used, the effec-
tive maximum supply voltage is increased. For example, when a
standard diode with a 0.7 V drop is used:
V
CC(max) = 9.9 V + 0.7 V = 10.6 V
Dynamic Self-Calibrating Peak-Detecting Dif ferential
Hall Ef fect Gear Tooth Sensor IC
ATS616LSG
13
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Device Evaluation: EMC (Electromagnetic Compatibility)
Characterization Only
Mechanical Information
Test Name* Reference Specification
200-001Q-CEAledoM ydoB namuH – DSE
300-001Q-CEAledoM enihcaM – DSE
1-7367 OSIstneisnarT detcudnoC
7-25411 OSInoitcejnI FR tceriD
4-25411 OSInoitcejnI tnerruC kluB
3-25411 OSIlleC MET
*Please contact Allegro MicroSystems for EMC performance
Component Material Description Value
Package Material Thermoset Epoxy Maximum Temperature 170°Ca
kciht .ni 610.0 reppoCsdaeL
aTemperature excursions of up to 225°C for 2 minutes or less are permitted.
bIndustry accepted soldering techniques are acceptable for this package as long as the indicated maximum temperature is not exceeded.
Additional soldering information is available on the Allegro Web site.
Dynamic Self-Calibrating Peak-Detecting Dif ferential
Hall Ef fect Gear Tooth Sensor IC
ATS616LSG
14
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Package SG, 4-Pin SIP
Copyright ©2005-2013, Allegro MicroSystems, LLC
Allegro MicroSystems, LLC 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
permit 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, LLC 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.
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±0.10 0.71±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
1A
A
D
B
For Reference Only, not for tooling use (reference DWG-9002)
Dimensions in millimeters
A
B
C
C
D
E
F
F
Dambar removal protrusion (16X)
Metallic protrusion, electrically connected to pin 4 and substrate (both sides)
Thermoplastic Molded Lead Bar for alignment during shipment
E
E2E1
Hall elements (E1, E2), not to scale
Active Area Depth, 0.43 mm
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
2.20
For the latest version of this document, visit our website:
www.allegromicro.com
