A3982SLBTR-TM24 - ALLEGRO MICROSYSTEMS

Description

The A3280, A3281, and A3283 Hall-effect latches are

ex treme ly temperature-stable and stress-resistant sensors

especially suited for operation over extended temperature

ranges to +150°C. Superior high-temperature per for mance

is made possible through dynamic offset cancellation,

which reduces the residual offset voltage normally caused

by device overmolding, temperature dependencies, and

thermal stress. The three devices are iden ti cal except for

mag net ic switch points.

Each device includes on a single silicon chip a voltage

regulator, Hall-voltage generator, small-signal amplifier,

chopper sta bi li za tion, Schmitt trigger, and a short-circuit

protected open-collector output to sink up to 25 mA.

A south pole of sufficient strength will turn the output

on. A north pole is necessary to turn the output off. An

on-board regulator permits operation with supply voltages

of 4.2 to 24 volts.

Three package styles provide a magnetically op ti mized

pack age for most ap pli ca tions. Package type LH is a

modified SOT23W surface-mount package, LT is a

miniature SOT89/TO-243AA transistor package for

surface-mount applications; while UA is a three-lead

ultra-mini-SIP for through-hole mounting. Each package

type is lead (Pb) free (suffix, –T), with 100% matte tin

leadframe plating.

27609.20-DS, Rev. H

Features and Benefits

▪ Symmetrical switch points

▪ Resistant to physical stress

▪ Superior temperature stability

▪ Output short-circuit protection

▪ Operation from unregulated supply

▪ Reverse battery protection

▪ Sol id-state reliability

▪ Small size

Chopper-Stabilized, Precision

Hall-Ef fect Latches

Packages:

Functional Block Diagram

Not to scale

A3280, A3281, and A3283

Package LH

Package LT Package UA

Chopper-Stabilized, Precision

Hall-Effect Latches

A3280, A3281

and A3283

Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Selection Guide

Part Number Packing1Mounting Ambient, TA

(°C)

BRP(MIN)

(TA = 25°C)

(G)

BOP(MAX)

(TA = 25°C)

(G)

A3280ELHLT-T 7-in. reel, 3000 pieces/reel SOT23W Surface Mount –40 to 85

–40 40

A3280EUA-T Bulk, 500 pieces/bag 3-pin SIP through hole

A3280LLHLT-T 7-in. reel, 3000 pieces/reel SOT23W Surface Mount

–40 to 150

A3280LLT-T2Bulk, 500 pieces/bag SOT89 Surface Mount

A3280LLTTR-T 7-in. reel, 1000 pieces/reel

A3280LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole

A3281ELHLT-T 7-in. reel, 3000 pieces/reel SOT23W Surface Mount –40 to 85

–90 90

A3281EUA-T3Bulk, 500 pieces/bag 3-pin SIP through hole

A3281LLHLT-T 7-in. reel, 3000 pieces/reel SOT23W Surface Mount

–40 to 150

A3281LLT-T2Bulk, 500 pieces/bag SOT89 Surface Mount

A3281LLTTR-T 7-in. reel, 1000 pieces/reel

A3281LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole

A3283ELHLT-T37-in. reel, 3000 pieces/reel SOT23W Surface Mount

–40 to 85

–180 180

A3283ELTTR-T 7-in. reel, 1000 pieces/reel SOT89 Surface Mount

A3283EUA-T Bulk, 500 pieces/bag 3-pin SIP through hole

A3283LLHLT-T 7-in. reel, 3000 pieces/reel SOT23W Surface Mount

–40 to 150

A3283LLT-T2Bulk, 500 pieces/bag SOT89 Surface Mount

A3283LLTTR-T 7-in. reel, 1000 pieces/reel

A3283LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole

1Contact Allegro for additional packing options.

2Variant is in production but has been determined to be LAST TIME BUY. This classification indicates that the variant is obsolete

and notice has been given. Sale of the variant is currently restricted to existing customer applications. The variant should not

be purchased for new design applications because of obsolescence in the near future. Samples are no longer available. Status

date change November 1, 2008. Deadline for receipt of LAST TIME BUY orders is May 1, 2008.

3Variant is in production but has been determined to be NOT FOR NEW DESIGN. This classification indicates that sale of the

variant is currently restricted to existing customer applications. The variant should not be purchased for new design applications

because obsolescence in the near future is probable. Samples are no longer available. Status change: November 1, 2008.

Absolute Maximum Ratings

Characteristic Symbol Notes Rating Units

Supply Voltage VCC 26.5 V

Reverse Battery Voltage VRCC –30 V

Magnetic Flux Density B Unlimited G

Output Off Voltage VOUT 26 V

Continuous Output Current IOUT

Internal current limiting is intended to protect

the device from output short circuits. 25 mA

Reverse Output Currrent IROUT –50 mA

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

Chopper-Stabilized, Precision

Hall-Effect Latches

A3280, A3281

and A3283

Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Sufﬁ x ‘–LH’ Pinning

(SOT23W)

Suffix '–LT' & '–UA' Pinning

(SOT89/TO-243AA & ultra-mini SIP)

Dwg. PH-003-2

SUPPLY

VCC

GROUND

OUTPUT

PTCT

Chopper-Stabilized, Precision

Hall-Effect Latches

A3280, A3281

and A3283

Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

ELECTRICAL CHARACTERISTICS over operating temperature range.

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Units

Supply Voltage Range VCC Operating, TJ < 170°C1 4.2 – 24 V

Output Leakage Current IOFF V

OUT = 24 V, B < BRP – – 10 μA

Output Saturation Voltage VOUT(SAT) I

OUT = 20 mA, B > BOP – 185 500 mV

Output Current Limit IOM B > BOP 30 – 60 mA

Power-On Time tpo V

CC > 4.2 V – – 50 μs

Chopping Frequency fC – 340 – kHz

Output Rise Time tr R

L = 820 , CL = 20 pF – 0.2 2.0 μs

Output Fall Time tf R

L = 820 , CL = 20 pF – 0.1 2.0 μs

Supply Current ICC B < BRP

, VCC = 12 V – 3.0 8.0 mA

B > BOP

, VCC = 12 V – 4.0 8.0 mA

Reverse Battery Current ICC V

RCC = -30 V – – -5.0 mA

Zener Voltage VZ + VD I

CC = 15 mA, TA = 25°C 28 32 37 V

Zener Impedance zz + zD I

CC = 15 mA, TA = 25°C – 50 – 

NOTES: 1. Maximum voltage must be adjusted for power dissipation and junction temperature.

2. BOP = operate point (output turns on); BRP = release point (output turns off).

3. Typical Data is at TA = +25°C and VCC = 12 V and is for design information only.

Part Numbers1

A3280 A3281 A3283

Characteristic Test Conditions Min. Typ. Max. Min. Typ. Max. Min. Typ. Max. Units

Operate Point, BOP at TA = +25°C and TA = max. 5.0 22 40 15 50 90 100 150 180 G

at TA = -40°C 5.0 – 40 15 – 90 100 – 200 G

Release Point, BRP at TA = +25°C and TA = max. -40 -23 -5.0 -90 -50 -15 -180 -150 -100 G

at TA = -40°C -40 – -5.0 -90 – -15 -200 – -100 G

Hysteresis, Bhys at TA = +25°C and TA = max. 10 45 80 30 100 180 – 300 360 G

(BOP - BRP) at TA = -40°C – – 80 – – 180 – – 360 G

NOTES: 1. Complete part number includes a sufﬁ x to identify operating temperature range (E or L) and package type (LH, LT, or UA).

2. As used here, negative ﬂ ux densities are deﬁ ned as less than zero (algebraic convention) and -50 G is less than +10 G.

3. Typical Data is at TA = +25°C and VCC = 12 V and is for design information only.

4. 1 gauss (G) is exactly equal to 0.1 millitesla (mT).

MAGNETIC CHARACTERISTICS over operating voltage range.

Chopper-Stabilized, Precision

Hall-Effect Latches

A3280, A3281

and A3283

Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

TYPICAL OPERATING CHARACTERISTICS

as a function of temperature

Chopper-Stabilized, Precision

Hall-Effect Latches

A3280, A3281

and A3283

Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

TYPICAL OPERATING CHARACTERISTICS

as a function of temperature (cont'd)

SUPPLY CURRENT

OUTPUT SATURATION VOLTAGE

4.0 4.5 5.0

SUPPLY VOLTAGE IN VOLTS

3.0

Dwg. GH-021-1

3.5

RELEASE POINT

-40

-80

OPERATE POINT

TA = 150°C

TA = -40°C

4.0 4.5 5.0

SUPPLY VOLTAGE IN VOLTS

3.0

Dwg. GH-021-3

3.5

RELEASE POINT

-20

-40

OPERATE POINT

= 150°C

= -40°C

0 25 50 75 100

300

AMBIENT TEMPERATURE IN °C

200

100

-50

Dwg. GH-029-4

150-25 125

OUT

= 20 mA

= 12 V

6.0

5.0

4.0

3.0

2.0

0 255075100

AMBIENT TEMPERATURE IN °C

-50

Dwg. GH-028-5

125-25 150

OUTPUT ON, B > B OP

OUTPUT OFF, B < B RP

VCC = 12 V

A3280* SWITCH POINTS A3281* SWITCH POINTS

TYPICAL OPERATING CHARACTERISTICS

as a function of supply voltage

Chopper-Stabilized, Precision

Hall-Effect Latches

A3280, A3281

and A3283

Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

TYPICAL OPERATING CHARACTERISTICS

as a function of supply voltage (cont’d)

4.0 4.5 5.0

SUPPLY VOLTAGE IN VOLTS

3.0

Dwg. GH-055-1

3.5 24

= 150°C

= +25°C

= -40°C

OUT

= 20 mA

250

150

200

225

175

4.0 6.0 9.0

SUPPLY VOLTAGE IN VOLTS

3.0

Dwg. GH-058-4

5.0 12

= 150°C

= +25°C

= -40°C

7.0

5.0

3.0

1.0

6.0

4.0

2.0

8.0

OUTPUT ON

10 118.07.0

SUPPLY CURRENT

OUTPUT SATURATION VOLTAGE

Chopper-Stabilized, Precision

Hall-Effect Latches

A3280, A3281

and A3283

Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

FUNCTIONAL DESCRIPTION

Chopper-Stabilized Technique. The Hall element can be

considered as a resistor array similar to a Wheatstone bridge. A

large portion of the offset is a result of the mismatching of these

resistors. These devices use a proprietary dynamic offset cancel-

lation technique, with an internal high-frequency clock to reduce

the residual offset voltage of the Hall element that is normally

caused by device overmolding, temperature de pen den cies, and

thermal stress. The chopper-stabilizing technique cancels the

mismatching of the resistor circuit by changing the direction of

the current ﬂ owing through the Hall plate using CMOS switches

and Hall voltage measurement taps, while maintaing the Hall-

voltage signal that is induced by the external magnetic ﬂ ux. The

signal is then captured by a sample-and-hold circuit and further

processed using low-offset bipolar circuitry. This technique

produces devices that have an extremely stable quiescent Hall

output voltage, are immune to thermal stress, and have precise

recoverability after temperature cycling. This technique will

also slightly degrade the device output repeatability. A relatively

high sampling frequency is used in order that faster signals can

be processed.

More detailed descriptions of the circuit operation can be

found in: Technical Paper STP 97-10, Monolithic Magnetic Hall

Sensor Using Dynamic Quadrature Offset Cancellation and

Technical Paper STP 99-1, Chopper-Stabilized Ampliﬁ ers With A

Track-and-Hold Signal Demodulator.

Operation. The output of these devices switch es low (turns

on) when a magnetic ﬁ eld perpendicular to the Hall sensor

exceeds the operate point threshold (BOP). After turn-on, the

output is capable of sinking 25 mA and the output voltage is

VOUT(SAT). Note that the de vice latch es; that is, a south pole of

sufﬁ cient strength towards the branded surface of the device

will turn the device on; removal of the south pole will leave

the device on. When the magnetic ﬁ eld is reduced below the

release point (BRP), the device output goes high (turns off).

The dif fer ence in the magnetic operate and release points is the

hysteresis (Bhys) of the device. This built-in hysteresis allows

clean switching of the output even in the presence of external

mechanical vibration and electrical noise.

Powering up in the absence of a magnetic ﬁ eld (less than

BOP and higher than BRP) will allow an indeterminate output

state. The correct state is warranted after the ﬁ rst excursion

beyond BOP or BRP.

It is strongly recommended that an external bypass ca pac i tor

Chopper-Stabilized, Precision

Hall-Effect Latches

A3280, A3281

and A3283

Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

be con nect ed (in close proximity to the Hall sensor) between the supply and ground of the device to reduce both external noise and

noise generated by the chopper-sta bi li za tion tech nique.

The sim plest form of magnet that will op er ate these devices is a ring magnet. Oth er meth ods of operation, such as linear magnets,

are possible.

Extensive applications information for Hall-effect sensors is available in:

• Hall-Effect IC Applications Guide, Application Note 27701;

• Guidelines for Designing Subassemblies Using Hall-Effect Devices, Application Note 27703.1

More detailed descriptions of the chopper-stabilized circuit operation can be found in:

• Monolithic Magnetic Hall Sensor Using Dynamic Quadrature Offset Cancelation, Technical Paper STP 97-10; and

• Chopper-Stabilized Ampliﬁ ers With A Track-and-Hold Signal Demodulator, Technical Paper STP 99-1.

All are provided at

www.allegromicro.com

APPLICATIONS INFORMATION

SUPPLY

OUTPUT

Dwg. EH-013

0.1 MF

SUPPLY

PTCT

Chopper-Stabilized, Precision

Hall-Effect Latches

A3280, A3281

and A3283

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

AActive Area Depth, 0.28 mm REF

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

PCB Layout Reference View

Standard Branding Reference View

Branded Face

N = Last two digits of device part number

T = Temperature code

NNT

2.90 +0.10

–0.20

4° +4°

–0°

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

1.49

0.96

Chopper-Stabilized, Precision

Hall-Effect Latches

A3280, A3281

and A3283

Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Package LT, 3-Pin SOT89

Parting

Line

2.24

1.14

321

AActive Area Depth, 0.78 mm REF

2X 1.50 BSC

4.50±0.10

1.50±0.10

0.50±0.06

0.42±0.06

1.73 +0.10

–0.11

2.20 +0.09

–0.07

2.45 +0.15

–0.16

4.10 +0.15

–0.16

1.00 +0.20

–0.11

0.40 +0.04

–0.05

Branding scale and appearance at supplier discretion

Hall element, not to scale

Reference land pattern layout (reference IPC7351 SOT89N);

All pads a minimum of 0.20 mm from all adjacent pads;

adjust as necessary to meet application process

requirements and PCB layout tolerances

Standard Branding Reference View

NNT

= Supplier emblem

N = Last two digits of device part number

T = Temperature code

For Reference Only; not for tooling use (reference JEDEC. TO-243AA)

Dimensions in millimeters

Dimensions exclusive of mold flash, gate burrs, and dambar protrusions

Exact case and lead configuration at supplier discretion within limits shown

1.50

1.00

0.80

2.60

2.00

2.50

0.70

4.60

BPCB Layout Reference View

Basic pads for low-stress, not self-aligning

Additional pad for low-stress, self-aligning

Additional area for IPC reference layout

Chopper-Stabilized, Precision

Hall-Effect Latches

A3280, A3281

and A3283

Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; 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 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

Package UA, 3-Pin SIP

231

1.27 NOM

2.16

MAX

0.51

REF

45°

0.79 REF

2.06

1.45

Gate burr area

Dambar removal protrusion (6X)

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

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