A3340LLHLT-T - Allegro MicroSystems, LLC

NOTE: For detailed information on purchasing options, contact your

local Allegro field applications engineer or sales representative.

Allegro MicroSystems, Inc. reserves the right to make, from time to time, revisions to the anticipated product life cycle plan

for a product to accommodate changes in production capabilities, alternative product availabilities, or market demand. The

information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no respon-

sibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use.

Recommended Substitutions:

Chopper-Stabilized, Precision Hall-Effect Switch

A3340

For existing customer transition, and for new customers or new appli-

cations, refer to the A1125.

Date of status change: November 1, 2010

This device is no longer in production. The device should not be

purchased for new design applications. Samples are no longer available.

Discontinued Product

Description

The A3340 Hall effect switch is an extremely temperature-stable

and stress-resistant sensor IC especially suited for operation

over extended temperature ranges up to 150°C. Superior

high-temperature performance is made possible through

dynamic offset cancellation, which reduces the residual offset

voltage normally caused by device overmolding, temperature

dependencies, and thermal stress.

The device includes on a single silicon chip a voltage regulator,

Hall-voltage generator, small-signal amplifier, chopper

stabilization, 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 off. An on-board regulator

permits operation with supply voltages of 4.2 to 24 volts.

Two package styles provide a magnetically optimized package

for most applications. Suffix LH is an SOT23W surface mount

package and while suffix UA is a three-lead ultramini SIP for

through hole mounting.

The A3340 complements the A3240, which offers the same

features, but with the opposite output polarity.

A3340-DS, Rev. 8

Features and Benefits

▪ 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 Switch

Packages: 3 pin SOT23W (suffix LH),

and 3 pin SIP (suffix UA)

Functional Block Diagram

Not to scale

A3340

Regulator

GND

VCC

VOUT

Control

Current Limit

<17

Dynamic Offset

Cancellation

Sample and Hold

To All Subcircuits

Amp Amp

Chopper-Stabilized, Precision Hall-Ef fect Switch

A3340

Allegro MicroSystems, Inc.

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

www.allegromicro.com

Selection Guide

Part Number Packing1Mounting Ambient, TABRP (Min) BOP (Max)

A3340EUA-T2Bulk, 500 pieces/bag 3-pin SIP through hole –40ºC to 85ºC 550

A3340LUA-T2Bulk, 500 pieces/bag 3-pin SIP through hole –40ºC to 150ºC

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 May 3, 2010. Deadline for receipt of LAST TIME

BUY orders is October 29, 2010.

Absolute Maximum Ratings

Characteristic Symbol Notes Rating Units

Supply Voltage VCC 26.5 V

Reverse Supply Voltage VRCC –30 V

Output Off Voltage VOUT 26 V

Reverse Output Voltage VROUT –0.5 V

Continuous Output Current IOUT

Internal current limiting (intended to protect the

device from output short circuits) 25 mA

Reverse Output Current IROUT –50 mA

Magnetic Flux Density BUnlimited 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

Chopper-Stabilized, Precision Hall-Ef fect Switch

A3340

Allegro MicroSystems, Inc.

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

www.allegromicro.com

Operating Characteristics, valid over TA, unless otherwise noted

Characteristic Symbol Test Conditions Min. Typ.1Max. Units

Electrical Characteristics

Supply Voltage Range2VCC Operating, TJ < 165°C 4.2 – 24 V

Output Leakage Current IOFF VOUT = 24 V, B > BOP ––10μA

Output Saturation Voltage VOUT(SAT) IOUT = 20 mA, B < BRP – 270 500 mV

Output Current Limit IOM B < BRP 30 – 60 mA

Power-On Time tPO VCC > 4.2 V – – 50 μs

Chopping Frequency fC– 340 – kHz

Output Rise Time trRLOAD = 820 Ω, CLOAD = 20 pF – 0.2 2.0 μs

Output Fall Time tfRLOAD = 820 Ω, CLOAD = 20 pF – 0.1 2.0 μs

Supply Current ICC B < BRP

, VCC = 12 V – 3.0 6.0 mA

B > BOP

, VCC = 12 V – 4.0 6.0 mA

Reverse Battery Current IRCC VRCC = –30 V – – -5.0 mA

Zener Voltage VZD VZ + VD, ICC = 15 mA, TA = 25°C 28 32 37 V

Zener Impedance ZZD ZZ + ZD, ICC = 15 mA, TA = 25°C – 50 – Ω

Magnetic Characteristics3

Operate Point4BOP –3550 G

Release Point4BRP 5.0 25 – G

Hysteresis Bhys BOP – BRP –6– G

1Typical data are for initial design estimations only, and assume optimum manufacturing and application conditions, such as TA = 25°C and VCC =

12 V. Performance may vary for individual units, within the specified maximum and minimum limits.

2Maximum voltage must be adjusted for power dissipation and junction temperature.

31 G (gauss) = 0.1 mT (millitesla).

4BOP = operate point (output turns off); BRP = release point (output turns on).

Chopper-Stabilized, Precision Hall-Ef fect Switch

A3340

Allegro MicroSystems, Inc.

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

www.allegromicro.com

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 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

20 40 60 80 100 120 140 160 180

Maximum Allowable V

(V)

TJ(max) = 165ºC; ICC = ICC(max)

Power Derating Curve

QJA

= 228 ºC/W)

Package LH, 1-layer PCB

QJA

= 110 ºC/W)

Package LH, 2-layer PCB

QJA

= 165 ºC/W)

Package UA, 1-layer PCB

VCC(min)

VCC(max)

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

(mW)

Power Dissipation versus Ambient Temperature

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

Chopper-Stabilized, Precision Hall-Ef fect Switch

A3340

Allegro MicroSystems, Inc.

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

www.allegromicro.com

TYPICAL OPERATING CHARACTERISTICS

as a function of temperature

SUPPLY CURRENT

B < BRP

SWITCHPOINTS

VCC = 12 V

050 100

AMBIENT TEMPERATURE IN oo

ooC

-50

SWITCH POINTS IN GAUSS

BOP

BRP

150 150-25 25 75 125

6.0

SUPPLY CURRENT IN mA

5.0

4.0

3.0

2.0

0255075100

AMBIENT TEMPERATURE IN oo

ooC

-50 125 05152-

OUTPUT SATURATION VOLTAGE

025 50 75 100

500

450

400

350

300

250

200

150

100

AMBIENT TEMPERATURE IN oo

ooC

-50

SATURATION VOLTAGE IN mV

52152-

VCC = 12 V, IOUT= 20 mA

SUPPLY CURRENT

B > BOP

6.0

SUPPLY CURRENT IN mA

5.0

4.0

3.0

2.0

0 25 50 75 100

AMBIENT TEMPERATURE IN oo

ooC

-50 125 05152-

VCC = 4.2 V

VCC = 12 V

VCC = 24 V

VCC = 4.2 V

VCC = 12 V

VCC = 24 V

Chopper-Stabilized, Precision Hall-Ef fect Switch

A3340

Allegro MicroSystems, Inc.

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

www.allegromicro.com

SUPPLY CURRENT

B > BOP

TYPICAL OPERATING CHARACTERISTICS

as a function of supply voltage

SUPPLY VOLTAGE IN VOLTS

SUPPLY CURRENT IN mA

SWITCHPOINTS

TA = 25°C

4 6 8 10 12 14 16 18 20 22 24

SUPPLY VOLTAGE IN VOLTS

SWITCH POINTS IN GAUSS

OUTPUT SATURATION VOLTAGE

IOUT = 20 mA

4 6 8 1012141618202224

SUPPLY VOLTAGE IN VOLTS

24 6 8 10121416182022242

SATURATION VOLTAGE IN mV

500

450

400

350

300

250

200

150

100

6.0

5.5

5.0

4.5

4.0

3.5

3.0

2.5

2.0

TA = –40°C

TA = 150°C

TA = 25°C

TA = –40°C

TA = 150°C

TA = 25°C

Chopper-Stabilized, Precision Hall-Ef fect Switch

A3340

Allegro MicroSystems, Inc.

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

www.allegromicro.com

Dwg. EH-012

REG

SAMPLE

& HOLD

–V

HALL

FLUX DENSITY

OPRP

OUTPUT VOLTAGE

OUT(SAT)

SUPPLY

OUTPUT

Dwg. EH-013

0.1 μF

SUPPLY

PTCT

VCC

GND

VOUT

Chopper -Stabilized Technique. The Hall element can be con-

sidered as a resistor array similar to a Wheatstone bridge. A large

portion of the offset is a result of the mismatching of these resis-

tors. These devices use a proprietary dynamic offset cancellation

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 dependencies, and thermal

stress. The chopper-stabilizing technique cancels the mismatch-

ing of the resistor circuit by changing the direction of the current

flowing through the Hall plate using CMOS switches and Hall

voltage measurement taps, while maintaining the Hall-voltage

signal that is induced by the external magnetic flux. The signal

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

cessed using low-offset bipolar circuitry. This technique produces

devices that have an extremely stable quiescent Hall output volt-

age, 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 Sensing

Using Dynamic Quadrature Offset Cancellation and Technical

Paper STP 99-1, Chopper-Stabilized Amplifiers With A Track-and-

Hold Signal Demodulator. Operation. The output of these devices

switches high (turns off) when a magnetic field (south pole) per-

pendicular to the Hall element exceeds the operate point thresh-

old (BOP). When the magnetic field is reduced below the release

point (BRP), the device output goes low (turns on). After turn-on,

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

VOUT(SAT). The difference in the magnetic operate and release

points is the hysteresis (Bhys) of the device. This built-in hyster-

esis allows clean switching of the output even in the presence of

external mechanical vibration and electrical noise. Applications.

It is strongly recommended that an external bypass capacitor be

connected (in close proximity to the Hall element) between the

supply and ground of the device to reduce both external noise and

noise generated by the chopper stabilization technique.

The simplest form of magnet that will operate these devices is a

ring magnet. Other methods of operation, such as linear magnets,

are possible. Extensive applications information on magnets and

Hall-effect devices is also available in Application Note 27701, or

at www.allegromicro.com.

FUNCTIONAL DESCRIPTION

Chopper-Stabilized, Precision Hall-Ef fect Switch

A3340

Allegro MicroSystems, Inc.

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

www.allegromicro.com

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

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

4°±4°

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

Package LH, 3-Pin (SOT-23W)

Pin-out Diagrams

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

Package LH

1 32

PTCT

VCC

GND

VOUT

Package UA

PTCT

GND

Chopper-Stabilized, Precision Hall-Ef fect Switch

A3340

Allegro MicroSystems, Inc.

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

www.allegromicro.com

Package UA, 3-Pin SIP

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

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