DESCRIPTION
The A1160 is a unipolar, Hall-effect switch with an externally
enabled diagnostic function. In normal operating mode, the
A1160 functions as a standard, unipolar Hall-effect switch.
The output transistor turns on (output signal switches low)
in the presence of a sufficient magnetic field (>BOP(max)).
Additionally, the output transistor of the A1160 switches
off (output signal switches high) when the magnetic field is
removed (< BRP(min)).
The A1160 includes conductive coils in close proximity to the
Hall element. When the diagnostic feature is enabled, these
coils are energized. The energized coils generate an internal
magnetic field that can be sensed by the Hall element. While
in Diagnostic mode, the output of the A1160 provides a square
wave output, which confirms the IC is properly sensing the
internally generated magnetic field. The Diagnostic mode
exercises the entire magnetic and electrical signal path internal
to the IC, fully confirming functionality. Therefore, use of the
A1160 either eliminates the need for redundant sensors in safety
critical applications or increases robustness in safety critical
applications that require redundant sensors (drive-by-wire
systems and so forth).
The A1160 Hall-effect sensor IC is extremely temperature-
stable and stress-resistant, especially suited for operation
A1160-DS, Rev. 3
MCO-0000560
FEATURES AND BENEFITS
• AEC-Q100 automotive qualified
• Unipolar switch points
• Externally enabled diagnostics feature
• Diagnostics feature exercises the entire magnetic and
electrical signal path within the IC
• Resistant to physical stress
• Superior temperature stability through advanced chopper
stabilization techniques
• Output short-circuit protection
• Internal regulator enables operation from unregulated
supplies
• Reverse-battery protection
• Solid-state reliability
• Small surface-mount package
Chopper-Stabilized Precision Hall-Effect Switch
with Advanced Diagnostics
Package: 5-pin SOT23W (suffix LH)
Functional Block Diagram
A1160
Continued on the next page…
Approximate footprint
VCC VOUT
To all subcircuits
Regulator
Dynamic Offset
Cancellation
Signal
Recovery
Control
Current
Limit
System Diagnostics
Threshold
Normal
Diagnostic
Hall
Element
VREG
DIAG
GND
Amplifier
February 4, 2020
Chopper-Stabilized Precision Hall-Effect Switch
with Advanced Diagnostics
A1160
2
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
Pinout Diagram
ABSOLUTE MAXIMUM RATINGS
Characteristic Symbol Notes Rating Unit
Forward Supply Voltage VCC 30 V
Reverse Supply Voltage VRCC –18 V
Forward Diagnostic Enable Voltage VDIAG 5.5 V
Reverse Diagnostic Enable Voltage VRDIAG –0.5 V
Output-Off Voltage VOUT 30 V
Continuous Output Current IOUT 25 mA
Reverse Output Current IROUT –50 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
Terminal List
Name Number Function
DIAG 1, 3 Diagnostics enable (use either pin 1 or pin 3)
VCC 2 Connects power supply to chip
GND 4 Ground
VOUT 5 Output from circuit
at temperature ranges up to 150°C. Superior high-temperature
performance is made possible through advanced dynamic offset
cancellation techniques, which reduce the residual offset voltage
normally caused by device overmolding, temperature dependencies,
and thermal stress. This device includes on a single silicon chip:
a voltage regulator, Hall-voltage generator, small-signal amplifier,
chopper stabilization, Schmitt trigger, and a open-drain output able
to sink up to 25 mA. An on-board regulator permits operation with
supply voltages of 3.8 to 24 V.
The A1160 is provided in a 5-pin SOT23W. The package is lead
(Pb) free, with 100% matte-tin leadframe plating.
DESCRIPTION (continued)
SELECTION GUIDE
Part Number Packing*
A1160LLHLX-T 10,000 pieces per 13-in. reel
*Contact Allegro™ for additional packing options.
1
5
Chopper-Stabilized Precision Hall-Effect Switch
with Advanced Diagnostics
A1160
3
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
OPERATING CHARACTERISTICS: Valid across full operating voltage and ambient temperature ranges, unless otherwise specified
Characteristic Symbol Test Conditions Min. Typ. [1] Max. Unit [2]
ELECTRICAL CHARACTERISTICS
Supply Voltage VCC
Operating, TJ < 165°C 3.8 – 24 V
VCC required for diagnostic functionality 3.8 – 24 V
Output Leakage Current IOUTOFF VOUT = 24 V, B < BRP – – 10 µA
Output Saturation Voltage VOUT(SAT) IOUT = 20 mA, B > BOP – 185 400 mV
Output Current Limit IOM B > BOP 30 – 60 mA
Power-On Time [3] tPN
VCC > 3.8 V , B < BRP(min) – 10 G,
B > BOP(max) + 10 G – – 25 µs
Chopping Frequency fC– 400 – kHz
Output Rise Time [3][4] trRLOAD = 820 Ω, CL = 20 pF – 0.2 2 µs
Output Fall Time [3][4] tfRLOAD = 820 Ω, CL = 20 pF – 0.1 2 µs
Supply Current [5]
ICC(ON) B < BRP , VCC = 12 V – – 5 mA
ICC(OFF) B > BOP , VCC = 12 V – – 5 mA
ICC(DIAG) VCC = 12 V, DIAG = 1 – 16 25 mA
Reverse Battery Current IRCC VRCC = –18 V – – –10 mA
Supply Zener Clamp Voltage VZSUP ICC = 8 mA, TA = 25°C 30 – – V
Output Zener Voltage VZOUT IOUT = 3 mA, TA = 25°C 28 – – V
PWM Carrier Frequency fPWMout With Diagnostic mode enabled – 3 – kHz
DIAGNOSTIC CHARACTERISTICS
Duty Cycle (Diagnostic Mode) [6] DFAIL DIAG = 1, device malfunction – ≈ 0 or
≈ 100 – %
DPASS DIAG = 1, device normal 40 50 60 %
DIAG Pin Input Resistance RDIAG Internal pulldown resistor – 1 – MΩ
DIAG Pin Input Low Voltage
Threshold VIL Device in Normal mode – – 0.6 V
DIAG Pin Input High Voltage
Threshold VIH Device in Diagnostic mode 1.5 – 5.0 V
Diagnostic Enable Time tD
Time from VIH reaching 1.5 to 5.0 V until valid
diagnostic output 1 – – ms
Diagnostic Disable Time tDIS
Time from DIAG pin release (high to low
transition) until valid normal sensor IC output – – 25 µs
Continued on the next page…
Chopper-Stabilized Precision Hall-Effect Switch
with Advanced Diagnostics
A1160
4
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
OPERATING CHARACTERISTICS (continued): Valid across full operating voltage and ambient temperature ranges,
unless otherwise specified
Characteristic Symbol Test Conditions Min. Typ. [1] Max. Unit [2]
Magnetic Characteristics [7]
Operate Point BOP 115 180 245 G
Release Point BRP 60 125 190 G
Hysteresis BHYS BOP – BRP 30 55 80 G
Maximum External Field in Diagnostic
Mode [8] BEXT(DIAG) 800 10,000 – G
Drift Detection Threshold
Operate Point Drift BOP(DRIFT) 30 – 420 G
Release Point Drift BRP(DRIFT) 15 – 325 G
[1] Typical data is at TA = 25°C and VCC = 12 V and it is for design information only.
[2] 1 G (gauss) = 0.1 mT (millitesla).
[3] Power-On Time, Output Rise Time, and Output Fall Time are ensured through device characterization and not final test.
[4] CL = oscilloscope probe capacitance.
[5] In Diagnostic mode the supply current level is different from the Normal mode operation current level. This is important when determining the power
derating for Diagnostic mode.
[6] When the A1160 passes the diagnostic tests, it outputs a 50% duty cycle signal. Any other output indicates the test failed. Please see the Diagnostic
Mode of Operation section for more information.
[7] Magnetic flux density, B, is indicated as a negative value for north-polarity magnetic fields, and as a positive value for south-polarity magnetic fields.
[8] 800 G is the maximum test capability due to practical equipment limitations. Design simulations show that a 10,000 G external field will not
adversely affect the A1160 in Diagnostic mode when a 1% sensitivity mismatch between the Hall elements in the IC is assumed.
Chopper-Stabilized Precision Hall-Effect Switch
with Advanced Diagnostics
A1160
5
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
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)
Power Derating Curve
V
CC
(max)
Normal Mode
(I
CC
(max) = 5 mA)
Diagnostic Mode
(I
CC
(max) = 25 mA)
V
CC
(min)
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)
Power Dissipation versus Ambient Temperature
Diagnostic Mode (ICC(max) = 25 mA)
Normal Mode (ICC(max) = 5 mA)
THERMAL CHARACTERISTICS: May require derating at maximum conditions; see application information
Characteristic Symbol Test Conditions* Value Unit
Package Thermal Resistance RθJA On 4-layer PCB based on JEDEC standard 124 °C/W
*Additional thermal information available on the Allegro website
Chopper-Stabilized Precision Hall-Effect Switch
with Advanced Diagnostics
A1160
6
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
CHARACTERISTIC PERFORMANCE
0
5
10
15
20
25
0 5 10 15 20 25 30
Supply Current, ICC(DIAG) (mA)
Supply Voltage, VCC (V)
ICC(DIAG) vs. VCC
-40°C
25°C
150°C
T
A
0
5
10
15
20
25
-50 0 50 100 150 200
Supply Current, I
CC(DIAG)
(mA)
Ambient Temperature, T
A
(°C)
I
CC(DIAG)
vs. T
A
3.8 V
V
CC
12 V
24 V
0 5 10 15 20 25 30
Supply Current, I
CC(OFF)
(mA)
Supply Voltage, V
CC
(V)
I
CC(OFF)
vs. V
CC
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
-40°C
25°C
150°C
T
A
-50 0 50 100 150 200
Supply Current, I
CC(OFF)
(mA)
Ambient Temperature, T
A
(°C)
ICC(OFF) vs. TA
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
3.8 V
V
CC
12 V
24 V
0 5 10 15 20 25 30
Supply Current, I
CC(ON)
(mA)
Supply Voltage, V
CC
(V)
I
CC(ON)
vs. V
CC
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
-40°C
25°C
150°C
T
A
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
-50 0 50 100 150 200
Supply Current, I
CC(ON)
(mA)
Ambient Temperature, T
A
(°C)
ICC(ON) vs. TA
3.8 V
V
CC
12 V
24 V
0
50
100
150
200
250
300
350
400
0 5 10 15 20 25 30
Output Saturaon Voltage, V
OUT(SAT)
(V)
Supply Voltage, V
CC
(V)
VOUT(SAT) vs. VCC
-40°C
25°C
150°C
T
A
0
50
100
150
200
250
300
350
400
-50 0 50 100 150 200
Output Saturaon Voltage, V
OUT(SAT)
(V)
Ambient Temperature, T
A
(°C)
V
OUT(SAT) vs. TA
3.8 V
V
CC
12 V
24 V
Chopper-Stabilized Precision Hall-Effect Switch
with Advanced Diagnostics
A1160
7
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
40
42
44
46
48
50
52
54
56
58
60
0 5 10 15 20 25 30
Normal DIAG Duty Cycle, D
PASS
(%)
Supply Voltage, V
CC
(V)
D
PASS
vs. V
CC
25°C
150°C
T
A
40
42
44
46
48
50
52
54
56
58
60
-50 0 50 100 150 200
Normal DIAG Duty Cycle, D
PASS
(%)
Ambient Temperature, T
A
(°C)
D
PASS
vs. T
A
3.8 V
V
CC
12 V
24 V
0
1
2
3
4
5
6
0 5 10 15 20 25 30
PWM Carrier Frequency, f
PWMout
(kHz)
Supply Voltage, V
CC
(V)
f
PWMout
vs. V
CC
25°C
150°C
T
A
0
1
2
3
4
5
6
-50 0 50 100 150 200
PWM Carrier Frequency, f
PWMout
(kHz)
Ambient Temperature, T
A
(°C)
fPWMout vs. TA
3.8 V
V
CC
12 V
24 V
Chopper-Stabilized Precision Hall-Effect Switch
with Advanced Diagnostics
A1160
8
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
30
35
40
45
50
55
60
65
70
75
80
0 5 10 15 20 25 30
Magnec Hysteresis, B
HYS
(G)
Supply Voltage, V
CC
(V)
B
HYS
vs. V
CC
-40°C
25°C
150°C
T
A
30
35
40
45
50
55
60
65
70
75
80
-50 0 50 100 150 200
Magnec Hysteresis, B
HYS
(G)
Ambient Temperature, T
A
(°C)
B
HYS
vs. T
A
3.8 V
VCC
12 V
24 V
55
75
95
115
135
155
175
195
0 5 10 15 20 25 30
Magnec Release Point, BRP (G)
Supply Voltage, V
CC
(V)
B
RP
vs. V
CC
-40°C
25°C
150°C
T
A
55
75
95
115
135
155
175
195
-50 0 50 100 150 200
Magnec Release Point, B
RP
(G)
Ambient Temperature, T
A
(°C)
B
RP
vs. T
A
3.8 V
VCC
12 V
24 V
110
130
150
170
190
210
230
250
0 5 10 15 20 25 30
Magnec Operate Point, BOP (G)
Supply Voltage, V
CC
(V)
B
OP
vs. V
CC
-40°C
25°C
150°C
T
A
110
130
150
170
190
210
230
250
-50 0 50 100 150 200
Magnec Operate Point, B
OP
(G)
Ambient Temperature, T
A
(°C)
B
OP
vs. T
A
3.8 V
VCC
12 V
24 V
Chopper-Stabilized Precision Hall-Effect Switch
with Advanced Diagnostics
A1160
9
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
FUNCTIONAL DESCRIPTION
Figure 1. Switching behavior of Hall effect switches. On the horizontal
axis, the B+ direction indicates increasing south polarity magnetic field
strength, and the B– direction indicates decreasing south polarity field
strength (including the case of increasing north polarity).
Figure 2. Typical application circuit
Operation
The output of the A1160 switches low (turns on) when a mag-
netic field perpendicular to the Hall element exceeds the oper-
ate point threshold, BOP . After turn-on, the output is capable of
sinking 25 mA and the output voltage is VOUT(SAT) . When the
magnetic field is reduced below the release point, BRP , the output
goes high (turns off). This is illustrated in figure 1.
The difference in the magnetic operate and release points is the
hysteresis, BHYS , of the IC. This built-in hysteresis allows clean
switching of the output, including when in the presence of exter-
nal mechanical vibration and electrical noise.
Powering-on the IC in the hysteresis range (applied magnetic
lower than BOP but also higher than BRP ) results in output at the
high state. The output will not switch until there is a valid transi-
tion beyond BOP or BRP . The correct output state is attained after
the first excursion beyond BOP or BRP .
Applications
It is strongly recommended that an external bypass capacitor be
connected between the supply and ground of the A1160 (in close
proximity to the device) to reduce both external noise and noise
generated by the chopper stabilization technique. As is shown in
figure 2, a 0.1 μF capacitor is typical.
Extensive applications information on magnets and Hall-effect
sensor ICs is available on the Allegro website, including the fol-
lowing application notes:
• Hall-Effect IC Applications Guide, AN27701
• Soldering Methods for Allegro’s Products – SMT and Through-
Hole, AN26009
BOP
BRP
BHYS
VCC
VOUT
VOUT(SAT)
Switch to Low
Switch to High
B+
0
V+
0
C
BYPASS
VCC
A1160
VOUT
GND
V+
C
L
(Optional)
Output
DIAG
From
Controller
R
L
Chopper-Stabilized Precision Hall-Effect Switch
with Advanced Diagnostics
A1160
10
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
Diagnostic Mode of Operation
The Diagnostic mode is accessed by applying a voltage of VIH on
the diagnostic enable pin (DIAG). The Diagnostic mode uses an
internally generated magnetic signal to exercise the signal path.
This signal is compared to two reference signals in the Schmitt
trigger.
If the diagnostic signal is between the two reference signals, the
device is considered to be working within specification and a
50% PWM signal is set at the output pin (VOUT), as shown in
figure 3. If the diagnostic signal is above the upper reference or
below the lower reference, the output PWM is set at a fixed value
that is either at nearly 0% or at nearly 100% duty cycle.
The Diagnostic mode of operation not only detects catastrophic
failures but also identifies drifts in the magnetic switch points. If
BOP or BRP drift to values below or above the values stated in the
Drift Detection Threshold section of the Operating Characteris-
tics table, the output PWM is set at a fixed value that is either at
nearly 0% or at nearly 100% duty cycle.
DIAG
Device OK
Duty = 50%
DIAG
t
t
t
t
Device Failure
VOUTVOUT
Duty or 50%
Duty 50%
Figure 3. Diagnostics Functional Diagram. When the A1160 passes the diagnostic test, a 50% duty cycle signal is
sent out (left panel). In the event of a failure, the output will be forced either high or low (right panel). Diagnostic
mode is only active when the DIAG input pin is pulled high.
Chopper-Stabilized Precision Hall-Effect Switch
with Advanced Diagnostics
A1160
11
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
Chopper Stabilization Technique
When using Hall-effect technology, a limiting factor for
switchpoint accuracy is the small signal voltage developed across
the Hall element. This voltage is disproportionally small relative
to the offset that can be produced at the output of the Hall IC.
This makes it difficult to process the signal while maintaining an
accurate, reliable output across the specified operating tempera-
ture and voltage ranges.
Chopper stabilization is a unique approach used to minimize
Hall offset on the chip. The Allegro technique, namely Dynamic
Quadrature Offset Cancellation, removes key sources of the out-
put drift induced by thermal and mechanical stresses. This offset
reduction technique is based on a signal modulation-demodula-
tion process. The unwanted offset signal is separated from the
magnetic field-induced signal in the frequency domain, through
modulation. The subsequent demodulation acts as a modulation
process for the offset, causing the magnetic field induced signal
to recover its original spectrum at baseband, while the DC offset
becomes a high-frequency signal. The magnetic sourced signal
then can pass through a low-pass filter, while the modulated DC
offset is suppressed. This configuration is illustrated in figure 4.
The chopper stabilization technique uses a 400 kHz, high
frequency clock. For demodulation process, a sample-and-hold
technique is used, where the sampling is performed at twice the
chopper frequency (800 kHz). This high-frequency operation
allows a greater sampling rate, which results in higher accuracy
and faster signal-processing capability. This approach desensi-
tizes the chip to the effects of thermal and mechanical stresses,
and produces devices that have extremely stable quiescent Hall
output voltages and precise recoverability after temperature
cycling. This technique is made possible through the use of a
BiCMOS process, which allows the use of low-offset, low-noise
amplifiers in combination with high-density logic integration and
sample-and-hold circuits.
The repeatability of magnetic field-induced switching is affected
slightly by a chopper technique. However, the Allegro high
frequency chopping approach minimizes the affect of jitter and
makes it imperceptible in most applications. Applications that are
more likely to be sensitive to such degradation are those requiring
precise sensing of alternating magnetic fields; for example, speed
sensing of ring-magnet targets. For such applications, Allegro
recommends its digital sensor IC families with lower sensitivity
to jitter. For more information on those products, contact your
Allegro sales representative.
Figure 4. Chopper stabilization circuit (Dynamic Quadrature Offset Cancellation)
Amp
Regulator
Clock/Logic
Hall Element
Sample and
Hold
Low-Pass
Filter
Chopper-Stabilized Precision Hall-Effect Switch
with Advanced Diagnostics
A1160
12
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
Package LH, 5-Pin SOT23W
SEATING
PLANE
C
0.55 REF
Gauge Plane
Seating Plane
0.25 BSC
0.95 BSC
0.95
1.00
0.70
0.20 MIN
2.40
2
1
AActive Area Depth, 0.28 mm REF
B
C
C
B
Reference land pattern layout
All pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary
to meet application process requirements and PCB layout tolerances
Branding scale and appearance at supplier discretion
A
PCB Layout Reference View
Standard Branding Reference View
1
Branded Face
N = Last three digits of device part number
NNN
2.90 +0.10
–0.20
4°±4°
8X 12° REF
0.18 +0.02
–0.05
0.05 +0.10
–0.05
0.25 MIN
1.91 +0.19
–0.06
2.98 +0.12
–0.08
1.00 ±0.13
0.40 ±0.10
For Reference Only; not for tooling use
Dimensions in millimeters
Dimensions exclusive of mold flash, gate burrs, and dambar protrusions
Exact case and lead configuration at supplier discretion within limits shown
DHall element, not to scale, location application dependant
D
5
Chopper-Stabilized Precision Hall-Effect Switch
with Advanced Diagnostics
A1160
13
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
REVISION HISTORY
Number Date Description
– December 12, 2013 Initial Release
1 September 21, 2015 Added AEC-Q100 qualification under Features and Benefits
2 January 25, 2019 Minor editorial updates
3 February 4, 2020 Minor editorial updates
Copyright 2020, Allegro MicroSystems.
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.