A1324, A1325, and A1326
Low Noise, Linear Hall Effect Sensor ICs with Analog Output
Features and Benefits
Description
Packages
These ratiometric Hall effect sensor ICs provide a voltage
output that is proportional to the applied magnetic field. They
feature a quiescent voltage output of 50% of the supply voltage.
The A1324/25/26 feature factory programmed sensitivities of
5.0 mV/G, 3.125 mV/G, and 2.5 mV/G, respectively.
• Temperature-stable quiescent output voltage and sensitivity
• Output voltage proportional to magnetic flux density
• Low-noise output increases accuracy
• Precise recoverability after temperature cycling
• Ratiometric rail-to-rail output
• Wide ambient temperature range: –40°C to 150°C
• Immune to mechanical stress
• Solid-state reliability
• Enhanced EMC performance for stringent automotive
applications
3-pin ultramini SIP
1.5 mm × 4 mm × 3 mm
(suffix UA)
3-pin SOT23-W
2 mm × 3 mm × 1 mm
(suffix LH)
New applications for linear output Hall-effect devices, such
as displacement, angular position, and current measurement,
require high accuracy in conjunction with small package size.
The Allegro™ A1324, A1325, and A1326 linear Hall-effect
sensor ICs are designed specifically to achieve both goals. This
temperature-stable device is available in a miniature surface
mount package (SOT23W) and an ultra-mini through-hole
single in-line package.
The features of these linear devices make them ideal for
use in automotive and industrial applications requiring high
accuracy, and operate through an extended temperature range,
–40°C to 150°C.
Each BiCMOS monolithic circuit integrates a Hall element,
temperature-compensating circuitry to reduce the intrinsic
sensitivity drift of the Hall element, a small-signal high-gain
amplifier, a clamped low-impedance output stage, and a
proprietary dynamic offset cancellation technique.
These devices are available in a 3-pin ultra-mini SIP package
(UA), and a 3-pin surface mount SOT-23 style package (LH). Both
are lead (Pb) free, with 100% matte tin leadframe plating.
Approximate footprint
Functional Block Diagram
V+
To All Subcircuits
Tuned Filter
Dynamic Offset
Cancellation
VCC
Sensitivity and
Sensitivity TC
Trim Control
GND
A1324-DS, Rev. 4
VOUT
Offset
A1324, A1325,
and A1326
Linear Hall Effect Sensor ICs with Analog Output
Selection Guide
Part Number
A1324LLHLT-T
Packing1
Sensitivity (Typ.)
(mV/G)
Package
3 000 pieces per reel
3-pin SOT-23W surface mount
A1324LLHLX-T
10 000 pieces per reel
3-pin SOT-23W surface mount
A1324LUA-T2
500 pieces per bag
3-pin ultramini SIP through hole mount
5.000
A1325LLHLT-T
3 000 pieces per reel
3-pin SOT-23W surface mount
A1325LLHLX-T
10 000 pieces per reel
3-pin SOT-23W surface mount
A1325LUA-T2
500 pieces per bag
3-pin ultramini SIP through hole mount
A1326LLHLT-T
3 000 pieces per reel
3-pin SOT-23W surface mount
A1326LLHLX-T
10 000 pieces per reel
3-pin SOT-23W surface mount
A1326LUA-T2
500 pieces per bag
3-pin ultramini SIP through hole mount
3.125
2.500
1Contact Allegro™
2Contact
for additional packing options.
factory for availability.
Absolute Maximum Ratings
Rating
Unit
Forward Supply Voltage
Characteristic
Symbol
VCC
Notes
8
V
Reverse Supply Voltage
VRCC
–0.1
V
Forward Output Voltage
VOUT
15
V
Reverse Output Voltage
VROUT
–0.1
V
Output Source Current
IOUT(SOURCE)
VOUT to GND
2
mA
IOUT(SINK)
VCC to VOUT
10
mA
Output Sink Current
Operating Ambient Temperature
TA
–40 to 150
ºC
Maximum Junction Temperature
TJ(max)
165
ºC
Tstg
–65 to 170
ºC
Storage Temperature
L temperature range
Thermal Characteristics may require derating at maximum conditions, see application information
Characteristic
Symbol
Test Conditions*
RθJA
Package Thermal Resistance
Value
Unit
Package LH, on 4-layer PCB with copper limited to solder pads
228
ºC/W
Package LH, on 2-layer PCB with 0.463 in.2 of copper area each
side, connected by thermal vias
110
ºC/W
Package UA, on 1-layer PCB with copper limited to solder pads
165
ºC/W
*Additional thermal information available on the Allegro website
Pin-out Diagrams
Terminal List Table
Name
3
1
2
LH Package
1
2
3
Number
Function
LH
UA
VCC
1
1
Input power supply; tie to GND with
bypass capacitor
VOUT
2
3
Output signal; also used for
programming
GND
3
2
Ground
UA Package
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
2
A1324, A1325,
and A1326
Linear Hall Effect Sensor ICs with Analog Output
OPERATING CHARACTERISTICS Valid throughout TA range, CBYPASS = 0.1 µF, VCC = 5 V; unless otherwise noted
Characteristics
Symbol
Test Conditions
Min.
Typ.
Max.
Unit1
Electrical Characteristics
Supply Voltage
VCC
4.5
5.0
5.5
V
Supply Current
ICC
No load on VOUT
–
6.9
9
mA
Power-On Time2
tPO
TA = 25°C, CL (PROBE) = 10 pF
–
32
–
µs
Supply Zener Clamp Voltage
VZ
TA = 25°C, ICC = 12 mA
6
8.3
–
V
Internal Bandwidth
Chopping Frequency3
BWi
fC
Small signal, –3 dB
–
17
–
kHz
TA = 25°C
–
400
–
kHz
Output Characteristics
Quiescent Voltage Output
Output Referred Noise
VOUT(Q)
VN
Input Referred RMS Noise Density
VNRMS
DC Output Resistance
ROUT
Output Load Resistance
Output Load Capacitance
Output Saturation Voltage
RL
CL
B = 0 G, TA = 25°C
2.425
2.500
2.575
V
A1324, TA = 25°C, CBYPASS = 0.1 µF
–
7.0
–
mV(p-p)
A1325, TA = 25°C, CBYPASS = 0.1 µF
–
4.4
–
mV(p-p)
A1326, TA = 25°C, CBYPASS = 0.1 µF
–
3.5
–
mV(p-p)
TA = 25°C, CBYPASS = open, no load on VOUT,
f |B(– )| .
SensB(+)
× 100%
SymERR = 1–
SensB(–)
(11)
where SensBx is defined as in equation 9, and B(+), B(–) are positive and negative magnetic fields such that |B(+)| = |B(–)|.
Ratiometry Error The A132x features a ratiometric output.
This means that the quiescent voltage output, VOUT(Q) , magnetic
sensitivity, Sens, and clamp voltages, VCLPHIGH and VCLPLOW ,
are proportional to the supply voltage, VCC. In other words, when
the supply voltage increases or decreases by a certain percentage, each characteristic also increases or decreases by the same
percentage. Error is the difference between the measured change
in the supply voltage, relative to 5 V, and the measured change in
each characteristic.
The ratiometric error in quiescent voltage output, RatVOUT(Q)
(%), for a given supply voltage, VCC, is defined as:
VOUT(Q)VCC ⁄ VOUT(Q)5V
× 100%
RatVOUT(Q) = 1–
VCC ⁄ 5 V
(12)
SensVCC ⁄ Sens5V
× 100%
RatVOUT(Q) = 1–
VCC ⁄ 5 V
(13)
The ratiometric error in magnetic sensitivity, RatSENS (%), for a
given supply voltage, VCC, is defined as:
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
6
A1324, A1325,
and A1326
Linear Hall Effect Sensor ICs with Analog Output
Typical Characteristics
(30 pieces, 3 fabrication lots)
Average Supply Current versus Ambient Temperature
VCC = 5 V
12
11
ICCav (mA)
10
9
8
7
6
5
4
– 40
25
150
TA (°C)
Average Negative Linearity versus Ambient Temperature
VCC = 5 V
105
105
104
104
103
103
102
102
Lin–av (%)
Lin+av (%)
Average Postive Linearity versus Ambient Temperature
VCC = 5 V
101
100
99
101
100
99
98
98
97
97
96
96
95
– 40
25
95
150
– 40
TA (°C)
Average Quiescent Voltage Output Ratiometry versus Ambient Temperature
102.0
100.6
VCC
5.5 to 5.0 V
100.4
4.5 to 5.0 V
100.2
100.0
99.8
99.6
VCC
5.5 to 5.0 V
101.5
RatSens(av) (%)
RatVOUTQ(av) (%)
150
Average Sensitivity Ratiometry versus Ambient Temperature
101.0
100.8
101.0
4.5 to 5.0 V
100.5
100.0
99.5
99.0
99.4
98.5
99.2
99.0
25
TA (°C)
– 40
25
TA (°C)
150
98.0
– 40
25
150
TA (°C)
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
7
A1324, A1325,
and A1326
Linear Hall Effect Sensor ICs with Analog Output
Typical Characteristics, continued
(30 pieces, 3 fabrication lots)
Average Absolute Quiescent Voltage Output versus Ambient Temperature
VCC = 5 V
Quiescent Voltage Output versus Supply Voltage
TA = 25°C
3.0
2.565
2.525
2.9
A1324
A1325
2.8
A1325
A1326
2.7
A1326
2.505
2.485
VOUT(Q) (V)
VOUT(Q)av (V)
2.545
A1324
2.6
2.5
2.4
2.3
2.465
2.2
2.445
2.1
2.0
2.425
– 40
25
150
4.5
TA (°C)
6.0
5.5
A1324
Sensav (mV/G)
Sensav (mV/G)
6.0
5.5
4.5
4.0
3.5
A1325
3.0
2.0
A1324
5.0
4.5
4.0
3.5
A1325
3.0
A1326
2.5
2.0
A1326
2.5
1.5
– 40
25
1.0
150
4.5
TA (°C)
10
8
8
6
6
4
4
∆Sensav (%)
10
2
0
-2
-4
5
VCC (V)
5.5
Average Sensitivity Drift versus Ambient Temperature
∆Sensav values relative to 25°C, VCC = 5 V
Average Quiescent Voltage Output Drift versus Ambient Temperature
∆VOUT(Q)av values relative to 25°C, VCC = 5 V
∆VOUT(Q)av (G)
5.5
Average Sensitivity versus Supply Voltage
TA = 25°C
Average Absolute Sensitivity versus Ambient Temperature
VCC = 5 V
5.0
5
VCC (V)
2
0
-2
-4
-6
-6
-8
-8
-10
-10
– 40
25
TA (°C)
150
– 40
25
150
TA (°C)
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
8
A1324, A1325,
and A1326
Linear Hall Effect Sensor ICs with Analog Output
V+
1[1]
VCC
VOUT
2[3]
VOUT
A132x
CBYPASS
0.1 µF
GND
3[2]
Pin numbers in brackets
refer to the UA package
Typical Application Circuit
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 over the specified operating temperature
and voltage ranges. Chopper stabilization is a unique approach
used to minimize Hall offset on the chip. Allegro employs a
technique to remove key sources of the output drift induced by
thermal and mechanical stresses. This offset reduction technique
is based on a signal modulation-demodulation process. The
undesired offset signal is separated from the magnetic fieldinduced 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. In addition to the removal of the thermal and stress
related offset, this novel technique also reduces the amount of
thermal noise in the Hall IC while completely removing the
modulated residue resulting from the chopper operation. The
chopper stabilization technique uses a high frequency sampling
clock. For demodulation process, a sample-and-hold technique
is used. This high-frequency operation allows a greater sampling
rate, which results in higher accuracy and faster signal-processing
capability. This approach desensitizes 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 highdensity logic integration and sample-and-hold circuits.
Regulator
Clock/Logic
Hall Element
Amp
Anti-Aliasing
LP Filter
Tuned
Filter
Concept of Chopper Stabilization Technique
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
9
A1324, A1325,
and A1326
Linear Hall Effect Sensor ICs with Analog Output
Package LH, 3-Pin SOT23W
+0.12
2.98 –0.08
1.49 D
3
+4°
4° –0°
A
+0.020
0.180–0.053
0.96 D
+0.10
2.90 –0.20
+0.19
1.91 –0.06
2.40
0.70
D
0.25 MIN
1.00
2
1
0.55 REF
0.25 BSC
0.95
Seating Plane
Gauge Plane
8X 10° REF
B
PCB Layout Reference View
Branded Face
1.00 ±0.13
0.95 BSC
+0.10
0.05 –0.05
0.40 ±0.10
NNN
1
C
Standard Branding Reference View
N = Last three digits of device part number
For Reference Only; not for tooling use (reference DWG-2840)
Dimensions in millimeters
Dimensions exclusive of mold flash, gate burrs, and dambar protrusions
Exact case and lead configuration at supplier discretion within limits shown
A
Active Area Depth, 0.28 mm REF
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
C
Branding scale and appearance at supplier discretion
D
Hall element, not to scale
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
10
A1324, A1325,
and A1326
Linear Hall Effect Sensor ICs with Analog Output
Package UA, 3-Pin SIP
+0.08
4.09 –0.05
45°
B
C
E
+0.08
3.02 –0.05
2.05 NOM
1.52 ±0.05
1.44 NOM
E
10°
Mold Ejector
Pin Indent
E
Branded
Face
A
1.02
MAX
45°
NNN
0.79 REF
1
D Standard Branding Reference View
1
2
= Supplier emblem
N = Last three digits of device part number
3
+0.03
0.41 –0.06
14.99 ±0.25
+0.05
0.43 –0.07
For Reference Only; not for tooling use (reference DWG-9065)
Dimensions in millimeters
Dimensions exclusive of mold flash, gate burrs, and dambar protrusions
Exact case and lead configuration at supplier discretion within limits shown
A
Dambar removal protrusion (6X)
B
Gate and tie bar burr area
C
Active Area Depth, 0.50 mm REF
D
Branding scale and appearance at supplier discretion
E
Hall element (not to scale)
1.27 NOM
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
11
A1324, A1325,
and A1326
Linear Hall Effect Sensor ICs with Analog Output
Revision History
Revision
Revision Date
Rev. 3
September 16, 2013
Update product selection
Description of Revision
Rev. 4
September 26, 2013
Fixed UA package drawing
Copyright ©2010-2013, 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 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 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.
For the latest version of this document, visit our website:
www.allegromicro.com
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
12