Description
The Allegro® A1101-A1104 and A1106 Hall-effect switches
are next generation replacements for the popular Allegro
312x and 314x lines of unipolar switches. The A110x family,
produced with BiCMOS technology, consists of devices that
feature fast power-on time and low-noise operation. Device
programming is performed after packaging, to ensure increased
switchpoint accuracy by eliminating offsets that can be induced
by package stress. Unique Hall element geometries and low-
offset amplifiers help to minimize noise and to reduce the
residual offset voltage normally caused by device overmolding,
temperature excursions, and thermal stress.
The A1101-A1104 and A1106 Hall-effect switches include
the following on a single silicon chip: voltage regulator,
Hall-voltage generator, small-signal amplifier, Schmitt
trigger, and NMOS output transistor. The integrated voltage
regulator permits operation from 3.8 to 24 V. The extensive
on-board protection circuitry makes possible a ±30 V absolute
maximum voltage rating for superior protection in automotive
and industrial motor commutation applications, without adding
A1101-DS, Rev. 12
Features and Benefits
▪ Continuous-time operation
▫ Fast power-on time
▫ Low noise
▪ Stable operation over full operating temperature range
▪ Reverse battery protection
▪ Solid-state reliability
▪ Factory-programmed at end-of-line for optimum
performance
▪ Robust EMC performance
▪ High ESD rating
▪ Regulator stability without a bypass capacitor
Continuous-Time Switch Family
Continued on the next page…
Packages: 3 pin SOT23W (suffix LH), and
3 pin SIP (suffix UA)
Functional Block Diagram
Not to scale
A1 101, A1102, A1 103, A1104, and A1 106
Amp
Regulator
GND
VCC
VOUT
OffsetGain
Trim
Control
To all subcircuits
Continuous-Time Switch Family
A1 101, A1102, A1 103,
A1104, and A1106
2
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Part Number Packing*Mounting Ambient, TABRP (Min) BOP (Max)
A1101ELHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount –40ºC to 85ºC
10 175
A1101EUA-T Bulk, 500 pieces/bag 3-pin SIP through hole
A1101LLHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount –40ºC to 150ºC
A1101LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole
A1102ELHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount –40ºC to 85ºC
60 245
A1102EUA-T Bulk, 500 pieces/bag 3-pin SIP through hole
A1102LLHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount –40ºC to 150ºC
A1102LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole
A1103ELHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount –40ºC to 85ºC
150 355A1103LLHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount –40ºC to 150ºC
A1103LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole
A1104EUA-T Bulk, 500 pieces/bag 3-pin SIP through hole –40ºC to 85ºC
25 450A1104LLHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount –40ºC to 150ºC
A1104LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole
A1106EUA-T Bulk, 500 pieces/bag 3-pin SIP through hole –40ºC to 85ºC
160 430A1106LLHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount –40ºC to 150ºC
A1106LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole
*Contact Allegro for additional packing options.
Selection Guide
external components. All devices in the family are identical except
for magnetic switchpoint levels.
The small geometries of the BiCMOS process allow these devices
to be provided in ultrasmall packages. The package styles available
provide magnetically optimized solutions for most applications.
Package LH is an SOT23W, a miniature low-profile surface-mount
package, while package UA is a three-lead ultramini SIP for through-
hole mounting. Each package is lead (Pb) free, with 100% matte
tin plated leadframes.
Absolute Maximum Ratings
Characteristic Symbol Notes Rating Units
Supply Voltage VCC 30 V
Reverse Supply Voltage VRCC –30 V
Output Off Voltage VOUT 30 V
Reverse Output Voltage VROUT –0.5 V
Output Current IOUTSINK 25 mA
Magnetic Flux Density B Unlimited G
Operating Ambient Temperature TA
Range E –40 to 85 ºC
Range L –40 to 150 ºC
Maximum Junction Temperature TJ(max) 165 ºC
Storage Temperature Tstg –65 to 170 ºC
Description (continued)
Continuous-Time Switch Family
A1 101, A1102, A1 103,
A1104, and A1106
3
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
ELECTRICAL OPERATING CHARACTERISTICS over full operating voltage and ambient temperature ranges, unless otherwise noted
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Supply Voltage1VCC Operating, TJ < 165°C 3.8 – 24 V
Output Leakage Current IOUTOFF VOUT = 24 V, B < BRP ––10A
Output On Voltage VOUT(SAT) IOUT = 20 mA, B > BOP – 215 400 mV
Power-On Time2tPO
Slew rate (dVCC/dt) < 2.5 V/s, B > BOP + 5 G or
B < BRP – 5 G ––4s
Output Rise Time3trVCC = 12 V, RLOAD = 820 , CS = 12 pF – – 400 ns
Output Fall Time3tfVCC = 12 V, RLOAD = 820 , CS = 12 pF – – 400 ns
Supply Current ICCON B > BOP – 4.1 7.5 mA
ICCOFF B < BRP – 3.8 7.5 mA
Reverse Battery Current IRCC VRCC = –30 V – – –10 mA
Supply Zener Clamp Voltage VZICC = 10.5 mA; TA = 25°C 32 – – V
Supply Zener Current4IZVZ = 32 V; TA = 25°C – – 10.5 mA
1 Maximum voltage must be adjusted for power dissipation and junction temperature, see Power Derating section.
2 For VCC slew rates greater than 250 V/s, and TA = 150°C, the Power-On Time can reach its maximum value.
3 CS =oscilloscope probe capacitance.
4 Maximum current limit is equal to the maximum ICC(max) + 3 mA.
DEVICE QUALIFICATION PROGRAM
Contact Allegro for information.
EMC (Electromagnetic Compatibility) REQUIREMENTS
Contact Allegro for information.
1
3
2
GND
VOUT
VCC
Package UA, 3-pin SIP
Package LH
1
2
3
GND
VOUT
VCC
Terminal List
Name Description Number
Package LH Package UA
VCC Connects power supply to chip 1 1
VOUT Output from circuit 2 3
GND Ground 3 2
Continuous-Time Switch Family
A1 101, A1102, A1 103,
A1104, and A1106
4
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
MAGNETIC OPERATING CHARACTERISTICS1 over full operating voltage and ambient temperature ranges, unless otherwise noted
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Operate Point BOP
A1101 TA = 25°C 50 100 160 G
Operating Temperature Range 30 100 175 G
A1102 TA = 25°C 130 180 230 G
Operating Temperature Range 115 180 245 G
A1103 TA = 25°C 220 280 340 G
Operating Temperature Range 205 280 355 G
A1104 TA = 25°C 70 – 350 G
Operating Temperature Range 35 – 450 G
A1106 TA = 25°C 280 340 400 G
Operating Temperature Range 260 340 430 G
Release Point BRP
A1101 TA = 25°C 10 45 130 G
Operating Temperature Range 10 45 145 G
A1102 TA = 25°C 75 125 175 G
Operating Temperature Range 60 125 190 G
A1103 TA = 25°C 165 225 285 G
Operating Temperature Range 150 225 300 G
A1104 TA = 25°C 50 – 330 G
Operating Temperature Range 25 – 430 G
A1106 TA = 25°C 180 240 300 G
Operating Temperature Range 160 240 330 G
Hysteresis BHYS
A1101 TA = 25°C 20 55 80 G
Operating Temperature Range 20 55 80 G
A1102 TA = 25°C 30 55 80 G
Operating Temperature Range 30 55 80 G
A1103 TA = 25°C 30 55 80 G
Operating Temperature Range 30 55 80 G
A1104 TA = 25°C 20 55 – G
Operating Temperature Range 20 55 – G
A1106 TA = 25°C 70 105 140 G
Operating Temperature Range 70 105 140 G
1 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.
This so-called algebraic convention supports arithmetic comparison of north and south polarity values, where the relative strength of the field is indicated
by the absolute value of B, and the sign indicates the polarity of the field (for example, a –100 G field and a 100 G field have equivalent strength, but
opposite polarity).
Continuous-Time Switch Family
A1 101, A1102, A1 103,
A1104, and A1106
5
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Characteristic Symbol Test Conditions Value Units
Package Thermal Resistance RθJA
Package LH, 1-layer PCB with copper limited to solder pads 228 ºC/W
Package LH, 2-layer PCB with 0.463 in.
2 of copper area each
side connected by thermal vias 110 ºC/W
Package UA, 1-layer PCB with copper limited to solder pads 165 ºC/W
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
Maximum Allowable V
CC
(V)
TJ(max) = 165ºC; ICC = ICC(max)
Power Derating Curve
(R
QJA
= 228 ºC/W)
Package LH, 1-layer PCB
(R
QJA
= 110 ºC/W)
Package LH, 2-layer PCB
(R
QJA
= 165 ºC/W)
Package UA, 1-layer PCB
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)
Power Dissipation versus Ambient Temperature
(R
QJA
= 165 ºC/W)
Package UA, 1-layer PCB
(RQJA = 228 ºC/W)
Package LH, 1-layer PCB
(RQJA = 110 ºC/W)
Package LH, 2-layer PCB
Continuous-Time Switch Family
A1 101, A1102, A1 103,
A1104, and A1106
6
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Characteristic Data
(A1101/02/03/04/06)
T
A
(°C)
Supply Current (On) versus Ambient Temperature
V
CC
(V)
ICCON (mA)
24
3.8
(A1101/02/03/04/06)
T
A
(°C)
Supply Current (Off) versus Ambient Temperature
V
CC
(V)
ICCOFF (mA)
24
3.8
(A1101/02/03/04/06)
T
A
(°C)
Output Voltage (On) versus Ambient Temperature
V
CC
(V)
VOUT(SAT) (mV)
24
3.8
(A1101/02/03/04/06)
Supply Current (On) versus Supply Voltage
T
A
(°C)
ICCON (mA)
V
CC
(V)
–40
25
150
(A1101/02/03/04/06)
Supply Current (Off) versus Supply Voltage
T
A
(°C)
ICCOFF (mA)
V
CC
(V)
–40
25
150
(A1101/02/03/04/06)
Output Voltage (On) versus Supply Voltage
T
A
(°C)
VOUT(SAT) (mV)
V
CC
(V)
–40
25
150
0
1.0
2.0
3.0
4.0
5.0
7.0
6.0
8.0
0
1.0
2.0
3.0
4.0
5.0
7.0
6.0
8.0
0
1.0
2.0
3.0
4.0
5.0
7.0
6.0
8.0
0
1.0
2.0
3.0
4.0
5.0
7.0
6.0
8.0
–50 0 50 100 150 0 5 10 15 20 25
–50 0 50 100 150 0 5 10 15 20 25
–50 0 50 100 150 0 5 10 15 20 25
0
50
100
150
200
250
300
350
400
0
50
100
150
200
250
300
350
400
Continuous-Time Switch Family
A1 101, A1102, A1 103,
A1104, and A1106
7
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Functional Description
OPERATION
The output of these devices switches low (turns on) when a
magnetic field (south polarity) perpendicular to the Hall ele-
ment exceeds the operate 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 device output goes high (turns off). The differ-
ence in the magnetic operate and release points is the hysteresis,
Bhys, of the device. This built-in hysteresis allows clean switch-
ing of the output, even in the presence of external mechanical
vibration and electrical noise.
Powering-on the device in the hysteresis region, less than BOP and
higher than BRP, allows an indeterminate output state. The correct
state is attained after the first excursion beyond BOP or BRP.
CONTINUOUS-TIME BENEFITS
Continuous-time devices, such as the A110x family, offer the
fastest available power-on settling time and frequency response.
Due to offsets generated during the IC packaging process,
continuous-time devices typically require programming after
packaging to tighten magnetic parameter distributions. In con-
trast, chopper-stabilized switches employ an offset cancellation
technique on the chip that eliminates these offsets without the
need for after-packaging programming. The tradeoff is a longer
settling time and reduced frequency response as a result of the
chopper-stabilization offset cancellation algorithm.
The choice between continuous-time and chopper-stabilized
designs is solely determined by the application. Battery manage-
ment is an example where continuous-time is often required. In
these applications, VCC is chopped with a very small duty cycle
in order to conserve power (refer to figure 2). The duty cycle
is controlled by the power-on time, tPO, of the device. Because
continuous-time devices have the shorter power-on time, they
are the clear choice for such applications.
For more information on the chopper stabilization technique,
refer to Technical Paper STP 97-10, Monolithic Magnetic Hall
Sensing Using Dynamic Quadrature Offset Cancellation and
Technical Paper STP 99-1, Chopper-Stabilized Amplifiers with a
Track-and-Hold Signal Demodulator.
Figure 1. Switching Behavior of Unipolar 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). This behavior can
be exhibited when using a circuit such as that shown in Panel B.
BOP
BRP
BHYS
VCC
VOUT
VOUT(SAT)
Switch to Low
Switch to High
B+
B–
V+
00
(A) (B)
VCC
VS
Output
GND
VOUT
RL
A110x
Continuous-Time Switch Family
A1 101, A1102, A1 103,
A1104, and A1106
8
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
ADDITIONAL APPLICATIONS INFORMA TION
Extensive applications information for Hall-effect devices is
available in:
• Hall-Effect IC Applications Guide, Application Note 27701
• Hall-Effect Devices: Gluing, Potting, Encapsulating, Lead
Welding and Lead Forming, Application Note 27703.1
• Soldering Methods for Allegro’s Products – SMT and Through-
Hole, Application Note 26009
All are provided in Allegro Electronic Data Book, AMS-702,
and the Allegro Web site, www.allegromicro.com.
Figure 2. Continuous-Time Application, B < BRP.. This figure illustrates the use of a quick cycle for chopping VCC in order to conserve battery power.
Position 1, power is applied to the device. Position 2, the output assumes the correct state at a time prior to the maximum Power-On Time, tPO(max).
The case shown is where the correct output state is HIGH . Position 3, tPO(max) has elapsed. The device output is valid. Position 4, after the output is
valid, a control unit reads the output. Position 5, power is removed from the device.
VCC
VOUT
Output Sampled
1 5 4
2
t
t
t
PO(max)
3
Continuous-Time Switch Family
A1 101, A1102, A1 103,
A1104, and A1106
9
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Power Derating
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 UA, using
minimum-K PCB.
Observe the worst-case ratings for the device, specifically:
RJA
=
165°C/W, TJ(max) =
165°C, VCC(max)
= 24 V, and
ICC(max) = 7.5 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 ÷ 165 °C/W = 91 mW
Finally, invert equation 1 with respect to voltage:
VCC(est) = PD(max) ÷ ICC(max) = 91 mW ÷ 7.5 mA = 12.1 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.
Continuous-Time Switch Family
A1 101, A1102, A1 103,
A1104, and A1106
10
Allegro MicroSystems, Inc.
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
Standard Branding Reference View
1
Branded Face
N = Last two digits of device part number
T = Temperature code
NNT
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
0.40 ±0.10
For Reference Only; not for tooling use (reference dwg. 802840)
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
D
D
D
1.49
0.96
3
Continuous-Time Switch Family
A1 101, A1102, A1 103,
A1104, and A1106
11
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Package UA, 3-Pin SIP
231
0.79 REF
1.27 NOM
2.16
MAX
0.51
REF
45°
C
45°
B
E
E
E
2.04
1.44
Gate burr area
A
B
C
Dambar removal protrusion (6X)
A
D
E
D
Branding scale and appearance at supplier discretion
Hall element, not to scale
Active Area Depth, 0.50 mm REF
For Reference Only; not for tooling use (reference DWG-9049)
Dimensions in millimeters
Dimensions exclusive of mold flash, gate burrs, and dambar protrusions
Exact case and lead configuration at supplier discretion within limits shown
Standard Branding Reference View
= Supplier emblem
N = Last two digits of device part number
T = Temperature code
NNT
1
Mold Ejector
Pin Indent
Branded
Face
4.09 +0.08
–0.05
0.41 +0.03
–0.06
3.02 +0.08
–0.05
0.43 +0.05
–0.07
15.75 ±0.51
1.52 ±0.05
Copyright ©2006-2009, Allegro MicroSystems, Inc.
Allegro MicroSystems, Inc. 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 per-
mit 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, Inc. 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.
For the latest version of this document, visit our website:
www.allegromicro.com
