Datasheet A3161EUA, A3161ELT Datasheet (Allegro)

27621.30A‡

Data Sheet

3161

HALL-EFFECT SWITCH

FOR 2-WIRE APPLICATIONS

This Hall-effect switch is a monolithic integrated circuit designed to
operate continuously over extended temperatures to +85°C. The unipo­lar switching characteristic makes this device ideal for use with a simple
bar or rod magnet. The A3161ELT and A3161EUA are identical except

X

V

CC

1

32

for package.

Each device includes a voltage regulator for operation with supply
voltages of 3.5 to 25 volts, reverse battery protection diode, quadratic
Hall-voltage generator, temperature compensation circuitry, small-signal
amplifier, Schmitt trigger, and a constant-current open-collector output.
Noise radiation is limited by control of the output current slew rate.

Two package styles provide a magnetically optimized package for
most applications. Suffix ‘LT’ is a miniature SOT-89/TO-243AA
transistor package for surface-mount applications; suffix ‘UA’ is a three­lead ultra-mini SIP for through-hole mounting.

SUPPLY

Pinning is shown viewed from branded side.

ABSOLUTE MAXIMUM RATINGS

at TA = +25°C

Supply Voltage, V

Continuous ................................. 28 V

Surge (tw ≤ 100 ms) .................... 40 V

Reverse Battery Voltage, V

Continuous ................................ -25 V

Surge (tw ≤ 100 ms) ................... -40 V

Magnetic Flux Density, B ....... Unlimited

Output OFF Voltage, V

Operating Temperature Range,

TA............................. -40°C to +85°C

Storage Temperature Range,

TS........................... -65°C to +170°C

GROUND

Dwg. PH-003-3

CC

OUT

OUTPUT

RCC

.............. 28 V

FEATURES and BENEFITS

■ Internal Current Regulator for 2-Wire Operation

■ Output Slew Rate Controlled

■ 3.5 V to 25 V Operation … Needs Only An Unregulated Supply

■ Reverse Battery Protection

■ Excellent Temp. Stability

■ Activate with Small, Commercially Available Permanent Magnets

■ Small Size

■ Solid-State Reliability … No Moving Parts

■ Resistant to Physical Stress

Always order by complete part number, e.g., A3161ELT .

3161

HALL-EFFECT SWITCH
FOR 2-WIRE APPLICATIONS

ELECTRICAL CHARACTERISTICS over operating voltage and temperature ranges.

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Units

Supply Voltage V

Load Current I

OUT

CC

+ I

CC

(2-wire application)

Output Current I

Output Saturation Voltage V

OUT

I

OFF

OUT

Output Slew Rate di/dt CL = 20 pF — 7.0 20 mA/µs

Operating 3.5 — 25 V

3.5 V ≤ V

≥ 12 V, B < B

V

OUT

B > B

OP

B < B

RP

V

= 24 V, B > B

OUT

I

= 5 mA, B < B

OUT

< 12 V, B < B

OUT

RP

OP

RP

RP

12 15 17 mA

12 15 19 mA

—3.55.0 mA

—12— mA

— <1.0 10 µA

–0.91.5 V

Output Settling Time t

sd

CL = 20 pF — — 20 µs

MAGNETIC CHARACTERISTICS over operating supply voltage range.

Limits

At TA = +25°C

Over Oper. Temp. Range

Characteristic Symbol Min. Typ. Max. Min. Typ. Max. Units

Operate Point (output turns OFF) B

Release Point (output turns ON) B

Hysteresis (BOP - BRP)B

OP

RP

hys

– 130 160 – 130 160 G

30 110 – 30 110 – G

5.0 20 – 5.0 20 80 G

NOTE:Typical values are at TA = +25°C and VCC = 12 V.

FUNCTIONAL BLOCK DIAGRAM

1

REG.

V

CC

3

OUTPUT

X

2

GROUND

Dwg. FH-017

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
Copyright © 1998, 1999, Allegro MicroSystems, Inc.

HALL-EFFECT SWITCH

FOR 2-WIRE APPLICATIONS

TYPICAL OPERATING CHARACTERISTICS

SWITCH POINTS TOTAL SUPPLY CURRENT

3161

200

150

OPERATE POINT

100

50

SWITCH POINT in GAUSS

0

-25 25 75 125

-50

0 50 100

AMBIENT TEMPERATURE in °C

OUTPUT SATURATION VOLTAGE SAFE OPERATING AREA

1200

RELEASE POINT

OVER OPER. VOLT. RANGE

Dwg. GH-044-1

150

20

VCC = 25 V

15

) in mA

CC

VCC = 3.5 V

+ I

OUT

10

5.0

VCC = 25 V

TOTAL SUPPLY CURRENT (I

VCC = 3.5 V

0

-50

0 255075100

AMBIENT TEMPERATURE in °C

30

B < B

B > B

RP

OP

125-25 150

Dwg. GH-028-4

1000

800

600

400

SATURATION VOLTAGE in mV

200

0

-50

-25

0 25 50 75

AMBIENT TEMPERATURE in °C

www.allegromicro.com

100

I

OUT

V

= 5 mA

CC

= 10 V

125

Dwg. GH-029-3

150

25

20

PACKAGE SUFFIX

CODE -UA

15

PACKAGE SUFFIX

CODE -LT

10

5

0

MAXIMUM CONTINUOUS SUPPLY VOLTAGE in VOLTS

40 80 120 180

20 60 100

AMBIENT TEMPERATURE in °C

140

160

Dwg. GH-068

3161

HALL-EFFECT SWITCH
FOR 2-WIRE APPLICATIONS

SENSOR LOCATIONS

Suffix “LT”

ACTIVE AREA DEPTH

0.030"

0.76 mm
NOM

A

1 32

Suffix “UA”

ACTIVE AREA DEPTH

0.018"

0.46 mm
NOM

A

BRANDED
SURFACE

1 32

Allegro

0.085"

2.16 mm

0.078"

1.98 mm

0.045"

1.14 mm

Dwg. MH-008-7

0.054"

1.36 mm

Dwg. MH-011-8

OPERATION

The output of these devices (pin 3) switches OFF when the magnetic
field at the Hall sensor exceeds the operate point threshold (BOP). When the
magnetic field is reduced to below the release point threshold (BRP), the
device output switches ON. The difference in the magnetic operate and
release points is called the hysteresis (B

) of the device. This built-in

hys

hysteresis allows clean switching of the output even in the presence of
external mechanical vibration and electrical noise.

15

12

9.0

6.0

TA = +25°C

OUTPUT CURRENT in mA

3.0

0

50250

MAGNETIC FLUX DENSITY in GAUSS

75

100 125 150 175 200

B

OP

B

RP

Dwg. GH-007-1

APPLICATIONS INFORMATION

These devices are normally operated in a 2-wire mode, where the supply
terminal and the output terminal are tied together. An external comparator
detects the change in total supply current by the addition (output off, B > BOP)
or subtraction (output on, B < BRP) of I

Hall effect applications information is available in the “Hall-Effect IC
Applications Guide”, which can be found in the latest issue of the Allegro
MicroSystems Electronic Data Book, AMS-702 or Application Note 27701,
or at www.allegromicro.com.

OUT

.

TYPICAL 2-WIRE APPLICATION

SUPPLY

UT

3

2

X

V

CC

1

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

0.1 µF

0.85 V

Icc + Io

–

+

100 Ω

Dwg. EH-011A

FOR 2-WIRE APPLICATIONS

PACKAGE DESIGNATOR ‘LT’

Dimensions in Inches

(for reference only)

3161

HALL-EFFECT SWITCH

0.167

0.155

0.047

0.035

0.059

BSC

0.181

0.173

0.072

0.064

0.102

1

23

0.090

0.0189

0.0142

0.0221

0.0173

0.118

BSC

Dimensions in Millimeters

(controlling dimensions)

4.60

4.40

1.83

1.62

0.063

0.055

0.090

0.084

1.60

1.40

0.0173

0.0138

Dwg. MA-009-3A in

0.44

0.35

www.allegromicro.com

4.25

3.94

1.20

0.89

1.50

BSC

1

23

3.00

BSC

0.56

0.44

2.60

2.29

0.48

0.36

2.29

2.13

Dwg. MA-009-3A mm

3161

HALL-EFFECT SWITCH
FOR 2-WIRE APPLICATIONS

PACKAGE DESIGNATOR ‘UA’

Dimensions in Inches Dimensions in Millimeters

(controlling dimensions) (for reference only)

SEE NOTE

45°

0.122

0.117

0.640

0.600

0.085

MAX

0.164

0.159

123

0.050

BSC

0.031

0.062

0.058

0.0189

0.0142

0.0173

0.0138

Dwg. MH-014E in

45°

SEE NOTE

45°

3.10

2.97

16.26

15.24

2.16

123

MAX

4.17

4.04

1.27

BSC

1.57

1.47

45°

0.79

0.44

0.35

0.48

0.36

Dwg. MH-014E mm

NOTES: 1. Tolerances on package height and width represent allowable mold offsets.

Dimensions given are measured at the widest point (parting line).

2. Exact body and lead configuration at vendor’s option within limits shown.

3. Height does not include mold gate flash.

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

3161

HALL-EFFECT SWITCH

FOR 2-WIRE APPLICATIONS

www.allegromicro.com

The products described herein are manufactured under one or more
of the following U.S. patents: 5,045,920; 5,264,783; 5,442,283;
5,389,889; 5,581,179; 5,517,112; 5,619,137; 5,621,319; 5,650,719;
5,686,894; 5,694,038; 5,729,130; 5,917,320; and other patents
pending.

Allegro MicroSystems, Inc. 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 products are not authorized for use as critical components
in life-support appliances, devices, or systems without express written
approval.

The information included herein is believed to be accurate and
reliable. However, Allegro MicroSystems, Inc. assumes no responsibil­ity for its use; nor for any infringements of patents or other rights of
third parties that may result from its use.

3161

HALL-EFFECT SWITCH
FOR 2-WIRE APPLICATIONS

HALL-EFFECT SENSORS

Partial Part Avail. Oper. Characteristics at TA = +25°C
Number Temp. B

HALL-EFFECT UNIPOLAR SWITCHES in order of B

3240 E/L +50 +5.0 10 chopper stabilized 1
3209 E ±60 ±5.0 7.7 400 µW, chopper stabilized
3210 E ±60 ±5.0 7.7 25 µW, chopper stabilized
3361 E +110 +55 5.0* 2-wire, chopper stabilized
3362 E +110 +55 5.0* 2-wire, chopper stabilized, inverted output
3161 E +160 +30 20 2-wire
3141 E/L +160 +10 55
3235 S +175 +25 15* output 1 2

5140 E +200 +50 55 300 mA power driver output 1
3142 E/L +230 +75 55
3143 E/L +340 +165 55
3144 E/L +350 +50 55
3122 E/L +400 +140 105
3123 E/L +440 +180 105
3121 E/L +450 +125 105

max B

OP

-25 -175 15* output 2 2

min B

RP

typ Features Notes

hys

and B

OP

hys

HALL-EFFECT LATCHES & BIPOLAR SWITCHES† in order of B

3260 E/L +30 -30 20 bipolar switch, chopper stabilized
3280 E/L +40 -40 45 chopper stabilized
3134 E/L +50 -50 27 bipolar switch
3133 K/L/S +75 -75 52 bipolar switch
3281 E/L +90 -90 100 chopper stabilized
3132 K/L/S +95 -95 52 bipolar switch
3187 E/L [phone]*
3177 S [phone]
3625 S [phone] mA power driver output 1, 3
3626 S [phone] mA power driver output 1, 3
3195 E/L [phone] active pulldown 1
3197 L [phone]
3175 S [phone]
3188 E/L [phone]*
3283 E/L [phone] chopper stabilized
3189 E/L [phone]*
3275 S [phone]* 3
3185 E/L [phone]*

Operating Temperature Ranges:

S = -20°C to +85°C, E = -40°C to +85°C, J = -40°C to +115°C, K = -40°C to +125°C, L = -40°C to +150°C

Notes 1. Protected.

2. Output 1 switches on south pole, output 2 switches on north pole for 2-phase, bifilar-wound, unipolar-driven brushless dc
motor control.

3. Complementary outputs for 2-phase bifilar-wound, unipolar-driven brushless dc motor control.
* Minimum. ‡ Maximum
† Latches will not switch on removal of magnetic field; bipolar switches may switch on removal of field but require field reversal

for reliable operation over operating temperature range.

OP

and B

hys

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]