DESCRIPTION
New applications for linear output Hall-effect sensors, such
as displacement and angular position, require higher accuracy
and smaller package sizes. The Allegro A1308 and A1309
linear Hall-effect sensor ICs have been designed specifically
to meet both requirements. These temperature-stable devices
are available in both surface-mount and through-hole packages.
The accuracy of each device is enhanced via end-of-line
optimization. Each device features nonvolatile memory to
optimize device sensitivity and the quiescent voltage output
(QVO: output in the absence of a magnetic field) for a given
application or circuit. This A1308 and A1309 optimized
performance is sustained across the full operating temperature
range by programming the temperature coefficient for both
sensitivity and QVO at Allegro end-of-line test.
These ratiometric Hall-effect sensor ICs provide a voltage
output that is proportional to the applied magnetic field. The
quiescent voltage output is adjusted around 50% of the supply
voltage.
The features of these linear devices make them ideal for use in
automotive and industrial applications requiring high accuracy,
and they operate across an extended temperature range,
–40°C to 150°C (SOT-23W) or –40°C to 125°C (SIP).
Each BiCMOS monolithic circuit integrates a Hall element,
temperature-compensating circuitry to reduce the intrinsic
A1308-9-DS, Rev. 7
FEATURES AND BENEFITS
5 V supply operation
QVO temperature coefficient programmed at Allegro for
improved accuracy
Miniature package options
High-bandwidth, low-noise analog output
High-speed chopping scheme minimizes QVO drift across
operating temperature range
Temperature-stable quiescent voltage output and sensitivity
Precise recoverability after temperature cycling
Output voltage clamps provide short-circuit diagnostic
capabilities
Undervoltage lockout (UVLO)
Wide ambient temperature range:
–40°C to 150°C (SOT-23W), –40°C to 125°C (SIP)
Immune to mechanical stress
Enhanced EMC performance for stringent automotive
applications
Linear Hall-Effect Sensor ICs with Analog Output
Available in a Miniature, Low-Profile Surface-Mount Package
Continued on the next page…
Functional Block Diagram
A1308 and A1309
V+
Offset and
Offset TC
Sensitivity and
Dynamic Offset
Cancellation
Tuned Filter
Sensitivity TC
VCC
CBYPASS
GND
VOUT
PACKAGES:
Not to scale
3-pin SOT-23W
2 mm × 3 mm × 1 mm
(suffix LH)
3-pin ultramini SIP
1.5 mm × 4 mm × 3 mm
(suffix UA)
January 4, 2017
Linear Hall-Effect Sensor ICs with Analog Output
Available in a Miniature, Low-Profile Surface-Mount Package
A1308 and
A1309
2
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
DESCRIPTION (continued)
ABSOLUTE MAXIMUM RATINGS
Characteristic Symbol Notes Rating Unit
Forward Supply Voltage VCC 8 V
Reverse Supply Voltage VRCC –0.1 V
Forward Output Voltage VOUT 7 V
Reverse Output Voltage VROUT –0.1 V
Output Source Current IOUT(SOURCE) VOUT to GND 2 mA
Output Sink Current IOUT(SINK) VCC to VOUT 10 mA
Operating Ambient Temperature TA
Range K –40 to 125 °C
Range L –40 to 150 °C
Maximum Junction Temperature TJ(max) 165 °C
Storage Temperature Tstg –65 to 170 °C
SELECTION GUIDE
Part Number Output
Polarity
Sensitivity
(typ) (mV/G)
Operating Ambient
Temperature Range
(TA) (°C)
Packing
[1] Package
A1308LLHLX-05-T Forward 0.5 –40 to 150 10,000 pieces per reel 3-pin SOT-23W surface mount
A1308KUA-1-T Forward 1.3 –40 to 125 500 pieces per bag 3-pin SIP through hole
A1308LLHLX-1-T Forward 1.3 –40 to 150 10,000 pieces per reel 3-pin SOT-23W surface mount
A1308LLHLX-2-T Forward 2.5 –40 to 150 10,000 pieces per reel 3-pin SOT-23W surface mount
A1308KUA-2-T Forward 2.5 –40 to 125 500 pieces per bag 3-pin SIP through hole
A1308KUA-3-T Forward 3.125 –40 to 125 500 pieces per bag 3-pin SIP through hole
A1308LLHLX-3-T Forward 3.125 –40 to 150 10,000 pieces per reel 3-pin SOT-23W surface mount
A1308KUA-5-T Forward 5 –40 to 125 500 pieces per bag 3-pin SIP through hole
A1308LLHLX-5-T Forward 5 –40 to 150 10,000 pieces per reel 3-pin SOT-23W surface mount
A1309LLHLX-9-T Forward 9 –40 to 150 10,000 pieces per reel 3-pin SOT-23W surface mount
A1309KUA-9-T Forward 9 –40 to 125 500 pieces per bag 3-pin SIP through hole
A1309LLHLX-RP9-T Reverse –9 –40 to 150 10,000 pieces per reel 3-pin SOT-23W surface mount
1 Contact Allegro for additional packing options.
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.
The A1308 and A1309 sensor ICs are offered in two package styles.
The LH is a SOT-23W style, miniature, low-profile package for
surface-mount applications. The UA is a 3-pin, ultramini, single
inline package (SIP) for through-hole mounting. Both packages are
lead (Pb) free, with 100% matte-tin leadframe plating.
Linear Hall-Effect Sensor ICs with Analog Output
Available in a Miniature, Low-Profile Surface-Mount Package
A1308 and
A1309
3
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
PINOUT DIAGRAMS AND TERMINAL LIST TABLE
2
1
3
2 31
THERMAL CHARACTERISTICS: May require derating at maximum conditions; see application information
Characteristic Symbol Test Conditions Value Units
Package Thermal Resistance RθJA
Package LH, 1-layer PCB with copper limited to solder pads 228 °C/W
Package LH, 2-layer PCB with 0.463 in.
2 of copper area each side
connected by thermal vias 110 °C/W
Package UA, 1-layer PCB with copper limited to solder pads 165 °C/W
Terminal List Table
Name Number Description
LH UA
VCC 1 1 Input power supply; tie to GND
with bypass capacitor
VOUT 2 3 Output signal
GND 3 2 Ground
LH Package
Pinout
UA Package
Pinout
Linear Hall-Effect Sensor ICs with Analog Output
Available in a Miniature, Low-Profile Surface-Mount Package
A1308 and
A1309
4
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
OPERATING CHARACTERISTICS: Valid through TA , CBYPASS = 0.1 µF, VCC = 5 V, unless otherwise noted
Characteristics Symbol Test Conditions Min. Typ. Max. Unit [1]
Continued on the next page…
ELECTRICAL CHARACTERISTICS
Supply Voltage VCC 4.5 5.0 5.5 V
Undervoltage Threshold
[2]
VUVLOHI
K temp. option tested at TA = 25°C to 125°C
(device powers on); L temp. option tested at TA =
25°C to 150°C (device powers on)
3 V
VUVLOLO
K temp. option tested at TA = 25°C to 125°C
(device powers off); L temp. option tested at TA =
25°C to 150°C (device powers off)
2.5 V
Supply Current ICC No load on VOUT 9 11.5 mA
Power-On Time
[3][4] tPO TA = 25°C, CL(PROBE) = 10 pF 50 µs
VCC Ramp Time
[3][4] tVCC TA = 25°C 0.005 100 ms
VCC Off Level
[3][4] VCCOFF TA = 25°C 0 0.55 V
Delay to Clamp
[3][4] tCLP TA = 25°C, CL = 10 nF 30 µs
Supply Zener Clamp Voltage VZTA = 25°C, ICC = 14.5 mA 6 7.3 V
Internal Bandwidth
[3] BWiSmall signal –3 dB 20 kHz
Chopping Frequency
[3][5] fCTA = 25°C 400 kHz
OUTPUT CHARACTERISTICS
Output Referred Noise
[3][6] VN
VCC = 5 V, TA = 25°C, CBYPASS = open,
Sens≥1.3mV/G,noloadonVOUT 1.7 G
VCC = 5 V, TA = 25°C, CBYPASS = open,
Sens = 0.5 mV/G, no load on VOUT 2.8 G
Input Referred RMS Noise Density
[3] VNRMS
VCC = 5 V, TA = 25°C, CBYPASS = open,
Sens≥1.3mV/G,noloadonVOUT 1.5 mG/√Hz
VCC = 5 V, TA = 25°C, CBYPASS = open,
Sens = 0.5 mV/G, no load on VOUT 2.5 mG/√Hz
DC Output Resistance
[3] ROUT 3 Ω
Output Load Resistance
[3] RLVOUT to GND 4.7
Output Load Capacitance
[3] CLVOUT to GND 10 nF
Output Voltage Clamp
[7][8] VCLPHIGH TA = 25°C, RL=10kΩ(VOUTtoGND) 4.35 4.5 4.65 V
VCLPLOW TA = 25°C, RL=10kΩ(VOUTtoVCC) 0.40 0.55 0.70 V
Sensitivity Sens
A1308LLHLX-05-T
TA = 25°C
0.43 0.5 0.57 mV/G
A1308KUA-1-T 1.17 1.3 1.43 mV/G
A1308LLHLX-1-T 1.17 1.3 1.43 mV/G
A1308LLHLX-2-T 2.4 2.5 2.6 mV/G
A1308KUA-2-T 2.4 2.5 2.6 mV/G
A1308KUA-3-T 3.025 3.125 3.225 mV/G
A1308LLHLX-3-T 3.025 3.125 3.225 mV/G
A1308KUA-5-T 4.85 5 5.15 mV/G
A1308LLHLX-5-T 4.85 5 5.15 mV/G
A1309LLHLX-9-T 8.73 9 9.27 mV/G
A1309KUA-9-T 8.73 9 9.27 mV/G
A1309LLHLX-RP9-T –9.27 –9 –8.73 mV/G
Quiescent Voltage Output (QVO) VOUT(Q) TA = 25°C 2.488 2.5 2.512 V
Sensitivity Temperature Coefficient TCSens
Programmed at TA = 125°C (K temp. option) or
150°C (L temp. option), calculated relative to
Sens at 25°C
0.08 0.12 0.16 %/°C
Linear Hall-Effect Sensor ICs with Analog Output
Available in a Miniature, Low-Profile Surface-Mount Package
A1308 and
A1309
5
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
OPERATING CHARACTERISTICS (continued): Valid through TA , CBYPASS = 0.1 µF, VCC = 5 V, unless otherwise noted
Characteristics Symbol Test Conditions Min. Typ. Max. Unit [1]
ERROR COMPONENTS
Linearity Sensitivity Error LinERR ±1.5 %
Symmetry Sensitivity Error SymERR ±1.5 %
Ratiometry Quiescent Voltage
Output Error
[9] RatVOUT(Q) Across supply voltage range (relative to VCC = 5 V) ±1.5 %
Ratiometry Sensitivity Error
[9] RatSens Across supply voltage range (relative to VCC = 5 V) ±1.5 %
Ratiometry Clamp Error
[10] RatVOUTCLP
TA = 25°C, across supply voltage range (relative
to VCC = 5 V) ±1.5 %
DRIFT CHARACTERISTICS
Typical Quiescent Voltage Output Drift
Across Temperature Range VOUT(Q)
A1308KUA-1-T
TA = 125°C
–15 0 15 mV
A1308KUA-2-T –10 0 10 mV
A1308KUA-3-T –10 0 10 mV
A1308KUA-5-T –20 0 10 mV
A1309KUA-9-T –20 0 10 mV
A1308LLHLX-05-T
TA = 150°C
–15 0 15 mV
A1308LLHLX-1-T –15 0 15 mV
A1308LLHLX-2-T –20 0 mV
A1308LLHLX-3-T –20 0 mV
A1308LLHLX-5-T –30 0 mV
A1309LLHLX-9-T –30 0 mV
A1309LLHLX-RP9-T –30 0 mV
Sensitivity Drift Due to
Package Hysteresis
[11] SensPKG TA = 25°C, after temperature cycling ±2 %
1
1 G (gauss) = 0.1 mT (millitesla),
2 On power-up, the output of the device is held low until VCC exceeds VUVLOHI. After the device is powered, the output remains valid until VCC drops
below VUVLOLO , when the output is pulled low.
3 Determined by design and characterization, not evaluated at final test.
4 See the Characteristic Definitions section.
5 fC varies as much as approximately ±20% across the full operating ambient temperature range and process.
6 Output Referred Noise is calculated as 6 sigma (6 standard deviations) from characterization of a small sample of devices. Conversion of noise from
gauss to mV(P-P) can be done by: Noise (G) × Sensitivity (mV/G) = Noise (mV(P-P)).
7 VCLPLOW and VCLPHIGH scale with VCC due to ratiometry.
8 Parameter is tested at wafer probe only.
9 Percent change from actual value at VCC = 5 V, for a given temperature.
10 Percent change from actual value at VCC = 5 V, TA = 25°C.
11 Sensitivitydriftthroughthelifeofthepart,ΔSensLIFE
, can have a typical error value ±3% in addition to package hysteresis effects.
Linear Hall-Effect Sensor ICs with Analog Output
Available in a Miniature, Low-Profile Surface-Mount Package
A1308 and
A1309
6
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
CHARACTERISTIC DEFINITIONS
Power-On Time. When the supply is ramped to its operating
voltage, the device output requires a finite time to react to an
input magnetic field. Power-On Time, tPO , is defined as the time
it takes for the output voltage to begin responding to an applied
magnetic field after the power supply has reached its minimum
specified operating voltage, VCC(min), as shown in Figure 1.
Delay to Clamp. A large magnetic input step may cause the
clamp to overshoot its steady-state value. The Delay to Clamp,
tCLP , is defined as the time it takes for the output voltage to settle
within 1% of its steady-state value, after initially passing through
its steady-state voltage, as shown in Figure 2.
Quiescent Voltage Output. In the quiescent state (no signifi-
cant magnetic field: B = 0 G), the output, VOUT(Q), is at a con-
stant ratio to the supply voltage, VCC, across the entire operating
ranges of VCC and Operating Ambient Temperature, TA.
Quiescent Voltage Output Drift Across Temperature
Range. Due to internal component tolerances and thermal
considerations, the Quiescent Voltage Output, VOUT(Q), may
drift due to temperature changes within the Operating Ambient
Temperature, TA. For purposes of specification, the Quiescent
Voltage Output Drift Across Temperature Range, ∆VOUT(Q) (mV),
is defined as:
VOUT(Q) VOUT(Q)(TA) VOUT(Q)(25°C)
=
(1)
Sensitivity. The amount of the output voltage change is propor-
tional to the magnitude and polarity of the magnetic field applied.
This proportionality is specified as the magnetic sensitivity,
Sens (mV/G), of the device and is defined as:
V
OUT(B+)
V
OUT(B–)
(B+) – (B–)
Sens = (2)
where B+ is the magnetic flux density in a positive field (south
polarity) and B– is the magnetic flux density in a negative field
(north polarity).
Sensitivity Temperature Coefficient. The device sensitiv-
ity changes as temperature changes, with respect to its Sensitiv-
ity Temperature Coefficient, TCSENS. TCSENS is programmed
at 150°C (L temperature device) or at 125°C (K temperature
device), and calculated relative to the baseline sensitivity pro-
gramming temperature of 25°C. TCSENS is defined as:
SensT2 – SensT1
SensT1 T2–T1
1
TCSens =×
100 (%/°C)
(3)
where T1 is the baseline Sens programming temperature of 25°C,
and T2 is the TCSENS programming temperature of 150°C (L
temperature device) or 125°C (K temperature device).
The ideal value of Sens across the full ambient temperature
range, SensIDEAL(TA), is defined as:
SensT1 × [100 (%) + TCSENS (TA T1
)]
SensIDEAL(TA) =
(4)
Sensitivity Drift Across Temperature Range. Second-
order sensitivity temperature coefficient effects cause the
magnetic sensitivity, Sens, to drift from its ideal value across the
operating ambient temperature range, TA. For purposes of specifi-
cation, the Sensitivity Drift Across Temperature Range, ∆SensTC,
V
+t
VCC
VCC(min)
VOUT
90% VOUT
0
t1= time at which power supply reaches
minimum specified operating voltage
t2=
time at which output voltage settles
within ±10% of its steady-state value
under an applied magnetic field
t1t2
tPO
V
CC
(typ)
time (µs)
Magnetic Input Signal
Magnetic Input Signal
t1= time at which output voltage initially
reaches steady-state clamp voltage
t2= time at which output voltage settles to
within 1% of steady-state clamp voltage
V
CLPHIGH
t1t2
tCLP
VOUT
Device Output, VOUT (V)
Figure 1: Denition of Power-On Time, tPO
Figure 2: Denition of Delay to Clamp, tCLP
Linear Hall-Effect Sensor ICs with Analog Output
Available in a Miniature, Low-Profile Surface-Mount Package
A1308 and
A1309
7
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
is defined as:
Sens
TA
– Sens
IDEAL(TA)
SensIDEAL(TA)
SensTC =×
100 (%)
(5)
Sensitivity Drift Due to Package Hysteresis. Package
stress and relaxation can cause the device sensitivity at TA = 25°C
to change during and after temperature cycling. This change in
sensitivity follows a hysteresis curve. For purposes of specifica-
tion, the Sensitivity Drift Due to Package Hysteresis, ∆SensPKG,
is defined as:
Sens
(25°C)(2)
– Sens
(25°C)(1)
Sens(25°C)(1)
SensPKG =×
100 (%) (6)
where Sens(25°C)(1) is the programmed value of sensitivity
at TA = 25°C, and Sens(25°C)(2) is the value of sensitivity at
TA = 25°C after temperature cycling TA up to 150°C (L tempera-
ture device) or 125°C (K temperature device), down to –40°C,
and back up to 25°C.
Linearity Sensitivity Error. The A1308 and A1309 are
designed to provide linear output in response to a ramping
applied magnetic field. Consider two magnetic fields, B1 and B2.
Ideally, the sensitivity of a device is the same for both fields, for
a given supply voltage and temperature. Linearity error is present
when there is a difference between the sensitivities measured at
B1 and B2.
Linearity Sensitivity Error, LINERR , is calculated separately for
positive (LinERR+) and negative (LinERR– ) applied magnetic
fields. LINERR (%) is measured and defined as:
Sens(B+)(2)
Sens(B+)(1)
Sens(B–)(2)
Sens(B–)(1)
1–
LinERR+ =×
100 (%)
×
100 (%)
1–
LinERR=
(7)
where:
|VOUT(Bx) VOUT(Q)|
Bx
SensBx= (8)
and Bx are positive and negative magnetic fields, with respect to
the quiescent voltage output, such that
|B(+)(2)| > |B(+)(1)| and |B(–)(2)| > |B(–)(1)|
The effective linearity error is:
max(|LinERR+| , |LinERR– |)
LinERR =
(9)
The output voltage clamps, VCLPHIGH and VCLPLOW
, limit the
operating magnetic range of the applied field in which the device
provides a linear output. The maximum positive and negative
applied magnetic fields in the operating range can be calculated:
VCLPHIGHVOUT(Q)
Sens
BMAX(+)
=
VOUT(Q)VCLPLOW
Sens
BMAX(–)
=
(10)
Symmetry Sensitivity Error. The magnetic sensitivity of the
device is constant for any two applied magnetic fields of equal
magnitude and opposite polarities. Symmetry error, SymERR (%),
is measured and defined as:
Sens(B+)
Sens(B–)
1–
SymERR =×
100 (%)
(11)
where SensBx is as defined in equation 10, and B+ and B– are
positive and negative magnetic fields such that |B+| = |B–|.
Ratiometry Error. The A1308 and A1309 provide 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)
VCC / 5 (V)
1–
RatVOUT(Q) =×
100 (%)
(12)
The ratiometric error in magnetic sensitivity, RatSens (%), for a
given supply voltage, VCC, is defined as:
Sens(VCC) / Sens(5V)
VCC / 5 (V)
1–
RatSens =×
100 (%)
(13)
The ratiometric error in the clamp voltages, RatVOUTCLP (%), for
a given supply voltage, VCC, is defined as:
VCLP(VCC) / VCLP(5V)
VCC / 5 (V)
1–
RatVOUTCLP =×
100 (%)
(14)
where VCLP is either VCLPHIGH or VCLPLOW
.
Linear Hall-Effect Sensor ICs with Analog Output
Available in a Miniature, Low-Profile Surface-Mount Package
A1308 and
A1309
8
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Undervoltage Lockout. The A1308 and A1309 provide an
undervoltage lockout feature which ensures that the device out-
puts a VOUT signal only when VCC is above certain thresholds
.
The undervoltage lockout feature provides a hysteresis of opera-
tion to eliminate indeterminate output states.
The output of the A1308 and A1309 is held low (GND) until
VCC exceeds VUVLOHI . After VCC exceeds VUVLOHI , the device
VOUT output is enabled, providing a ratiometric output voltage
that is proportional to the input magnetic signal and VCC . If VCC
should drop back down below VUVLOLO for longer than tUVLO
after the device is powered up, the output would be pulled low
(see Figure 3) until VUVLOHI is reached again and VOUT would
be reenabled.
VCC Ramp Time. The time taken for VCC to ramp from 0 V to
VCC(typ), 5 V (see Figure 4).
VCC Off Level. For applications in which the VCC pin of the
A1308 or A1309 is being power-cycled (for example using a
multiplexer to toggle the part on and off), the specification of
VCC Off Level, VCCOFF , determines how high a VCC off voltage
can be tolerated while still ensuring proper operation and startup
of the device (see Figure 4).
Figure 3: Denition of Undervoltage Lockout
VOUT
tUVLO
VCC
VUVLOHI
VUVLOLO
time
time
V
CC
(typ)
V
CCOFF
0
tVCC
Supply Voltage, VCC (V)
Figure 4: Denition of VCC Ramp Time, tVCC
Linear Hall-Effect Sensor ICs with Analog Output
Available in a Miniature, Low-Profile Surface-Mount Package
A1308 and
A1309
9
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
A1308
A1309
VOUT
GND
0.1
5 V µF
RL
VCC
4.7 nF
APPLICATION INFORMATION
Figure 5: Typical Application Circuit
Figure 6: Chopper Stabilization Technique
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 sensor
IC. This makes it difficult to process the signal while maintain-
ing 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 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 sup-
pressed. In addition to the removal of the thermal and mechanical
stress-related offset, this novel technique also reduces the amount
of thermal noise in the Hall sensor 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 high-
density logic integration and sample-and-hold circuits.
Amp
Regulator
Clock/Logic
Hall Element
Tuned
Filter
Anti-aliasing
LP Filter
Linear Hall-Effect Sensor ICs with Analog Output
Available in a Miniature, Low-Profile Surface-Mount Package
A1308 and
A1309
10
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Package LH, 3-Pin (SOT-23W)
0.55 REF
Gauge Plane
Seating Plane
0.25 BSC
0.95 BSC
0.95
1.00
0.70
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
Branding Reference View
Branded Face
2.90 +0.10
–0.20
4°±4°
8X 10° REF
0.180+0.020
–0.053
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
1
NNN
0.40 ±0.10
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
DHall element, not to scale
NNN
308
308
308
308
308
309
09R
D
D
D
1.49
0.96
3
Linear Hall-Effect Sensor ICs with Analog Output
Available in a Miniature, Low-Profile Surface-Mount Package
A1308 and
A1309
11
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Package UA, 3-Pin SIP
2 31
1.27 NOM
1.02
MAX
45°
45°
C
1.52 ±0.05
B
Gate and tie bar burr area
A
B
C
Dambar removal protrusion (6X)
A
D
E
E
E
1.44
2.04
E
Active Area Depth, 0.50 mm REF
Branding scale and appearance at supplier discretion
Hall element (not to scale)
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
Mold Ejector
Pin Indent
DStandard Branding Reference View
= Supplier emblem
N = Last three digits of device part number
NNN
1
0.41 +0.03
–0.06
0.43 +0.05
–0.07
14.99 ±0.25
4.09 +0.08
–0.05
3.02 +0.08
–0.05
0.79 REF
10°
Branded
Face
Linear Hall-Effect Sensor ICs with Analog Output
Available in a Miniature, Low-Profile Surface-Mount Package
A1308 and
A1309
12
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
For the latest version of this document, visit our website:
www.allegromicro.com
Revision History
Number Date Description
June 27, 2014 Initial release
1 June 27, 2014 Updated product offerings
2 November 13, 2015 Updated product offerings
3 March 30, 2016 Updated product offerings
4 April 19, 2016 Updated product offerings
5 September 2, 2016 Updated product offerings
6 December 9, 2016 Updated product offerings
7 January 4, 2017 Updated product offerings
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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.
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