3054

3054

MULTIPLEXED

TWO-WIRE

HALL-EFFECT SENSOR ICs

The A3054KU and A3054SU Hall-effect sensors are digital mag-

netic sensing ICs capable of communicating over a two-wire power/

signal bus. Using a sequential addressing scheme, the device re-

sponds to a signal on the bus and returns the diagnostic status of the

IC, as well as the status of each monitored external magnetic field.

As many as 30 sensors can function on the same two-wire bus. This

IC is ideal for multiple sensor applications where minimizing the wiring

harness size is desirable or essential.

Each device consists of high-resolution bipolar Hall-effect switch-

ing circuitry, the output of which drives high-density CMOS logic

stages. The logic stages decode the address pulse and enable a

response at the appropriate address. The combination of magnetic-

field or switch-status sensing, low-noise amplification of the Hall-

transducer output, and high-density decoding and control logic is made

possible by the development of a new sensor DABiC™ (digital analog

bipolar CMOS) fabrication technology. The A3054SU is an improved

replacement for the original UGN3055U.

These unique magnetic sensing ICs are available in two tempera-

ture ranges; the A3054SU operates within specifications between

-20

C and +85

C, while the A3054KU is rated for operation between

-40

C and +125

C. Alternative magnetic and temperature specifica-

tions are available on special order. Both versions are supplied in

0.060" (1.54 mm) thick, three-pin plastic SIPs. Each device is clearly

marked with a two-digit device address (XX).

3054

MULTIPLEXED TWO-WIRE

HALL-EFFECT SENSOR ICs

FEATURES

Complete Multiplexed Hall-Effect ICs with

Simple Sequential Addressing Protocol

Allows Power and Communication Over a

Two-Wire Bus (Supply/Signal and Ground)

Up to 30 Hall-Effect Sensors Can Share a Bus

Sensor Diagnostic Capabilities

Magnetic-Field or Switch-Status Sensing

Low Power of DABiC Technology Favors

Battery-Powered and Mobile Applications

Ideal for Automotive, Consumer, and Industrial Applications

Always order by complete part number:

Part Number

Operating Temperature Range

A3054KU-XX

-40

C to +125

A3054SU-XX

-20

C to +85

where XX = address (01, 02, … 29, 30).

Pinning is shown viewed from branded side.

ABSOLUTE MAXIMUM RATINGS

at T

= +25

Supply Voltage, V

BUS

. . . . . . . . . . . . . . 18 V

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

Operating Temperature Range, T

A3054KU . . . . . . . . . . . -40

C to +125

A3054SU . . . . . . . . . . . . -20

C to +85

Storage Temperature Range,

. . . . . . . . . . . . . . . . . -55

C to +150

Package Power Dissipation,

. . . . . . . . . . . . . . . . . . . . . . . 635 mW

Data Sheet

27680.1

Dwg. PH-005

BUS

GROUND

SWITCH IN

LOGIC

3054

MULTIPLEXED

TWO-WIRE

HALL-EFFECT SENSOR ICs

115 Northeast Cutoff, Box 15036

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

Limits

Characteristic

Symbol

Test Conditions

Min

Typ

Max

Units

Power Supply Voltage

BUS

—

Signal Current

DUT Addressed, B > 300 G

Quiescent Current

BUS

= 6 V

—

1.5

2.5

BUS

= 9 V

—

1.4

2.5

∆

– I

—

100

300

Address Range

Addr

Factory Specified

—

Clock Thresholds

CLH

LOW to HIGH

—

8.5

CHL

HIGH to LOW

6.5

—

CHYS

Hysteresis

—

0.8

—

Max. Clock Frequency*

CLK

50% Duty Cycle

2.5

—

kHz

Address LOW Voltage

RST

6.0

CHL

Address HIGH Voltage

CLH

9.0

BUS

Reset Voltage

RST

2.5

3.5

5.5

Propagation Delay*

plh

LOW to HIGH

phl

HIGH to LOW

—

5.0

Pin 3-2 Resistance

SWH

DUT Addressed, B < 5 G

—

Ω

SWL

DUT Addressed, B > 300 G

—

200

—

Ω

Pin 3-2 Output Voltage

SWH

DUT Addressed, B < 5 G

—

3.9

—

SWL

DUT Addressed, B> 300 G

—

MAGNETIC CHARACTERISTICS over operating temperature range.

Limits

Characteristic

Symbol

Test Conditions

Min.

Typ.

Max.

Units

Magnetic Threshold†

Turn-On

150

300

Turn-Off

5.0

100

295

Hysteresis

HYS

– B

5.0

—

ELECTRICAL CHARACTERISTICS over operating temperature range.

Typical Data is at T

= +25

C and is for design information only.

*This parameter, although warranteed, is not production tested.

†Alternative magnetic switch point specifications are available on special order. Please contact the factory.

3054

MULTIPLEXED

TWO-WIRE

HALL-EFFECT SENSOR ICs

FUNCTIONAL BLOCK DIAGRAM

SENSOR LOCATION

(

0.005” [0.13 mm] die placement)

CLOCK

Dwg. FH-009

BUS

SWITCH IN

(OPTIONAL)

GROUND

CMOS LOGIC

REG

COMP

RESET

Dwg. MH-002-10A

0.015"

0.38 mm

NOM

BRANDED

SURFACE

ACTIVE AREA DEPTH

0.073"

1.85 mm

0.090"

2.29 mm

DEFINITION OF TERMS

Sensor Address

Each bus sensor has a factory-specified predefined

address. At present, allowable sensor addresses are

integers from 01 to 30.

LOW-to-HlGH Clock Threshold (V

CLH

)

Minimum voltage required during the positive-going

transition to increment the bus address and trigger a

diagnostic response from the bus sensors. This is also

the maximum threshold of the on-chip comparator that

monitors the supply voltage, V

BUS

HlGH-to-LOW Threshold (V

)

Maximum voltage required during the negative-going

transition to trigger a

signal current response from the bus

sensors. This is also the maximum threshold of the

on-chip comparator that monitors the supply voltage,

BUS

Bus HIGH Voltage (V

)

Bus HIGH voltage during addressing. Voltage should

be greater than V

CLH

Address LOW Voltage (V

)

Bus LOW voltage during addressing. Voltage should

be greater than V

RST

and less than V

CHL

Bus Reset Voltage (V

RST

)

Voltage level while resetting sensors.

Sensor Quiescent Current Drain (I

)

The current drain of bus sensors when active but not

addressed. I

is the quiescent current drain when the

sensor is not addressed and is at V

is the quiescent

current drain when the sensor is not addressed and is at

. Note that I

is greater than I

Diagnostic Phase

Period on the bus when the address voltage is at V

During this period, a correctly addressed sensor responds

by increasing its current drain on the bus. This response

from the sensor is called the diagnostic response and

the bus current

increase is called the diagnostic current.

Signal Phase

Period on the bus when the address voltage is at V

During this period, a correctly addressed sensor that

detects a magnetic field greater than the magnetic oper-

ate point, B

, responds by maintaining a current drain of

on the bus. This response from the sensor is called the

signal response and the bus current is called the signal

current.

Sensor Address Response Current (I

)

Sensor current during the

diagnostic and the signal

responses of the bus sensor. This is accomplished by

enabling an internal constant-current source.

3054

MULTIPLEXED

TWO-WIRE

HALL-EFFECT SENSOR ICs

115 Northeast Cutoff, Box 15036

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

A device may be addressed by changing the supply

voltage as shown in Figure 1. A preferred addressing

protocol is as follows: the bus supply voltage is brought

low (<2.5 V) so that all devices on the bus are reset. The

voltage is then raised to the address LOW voltage (V

) and

the bus quiescent current is measured. The bus is then

toggled between V

and V

(address HIGH voltage), with

each positive transition representing an increment in the

bus address. After each voltage transition, the bus current

may be monitored to check for diagnostic and signal

responses from sensor ICs.

Sensor Addressing

When a sensor detects a bus address equal to its

factory-programmed address, it responds with an increase

in its supply current drain ( I

) during the next HIGH portion

ADDRESSING PROTOCOL

Magnetic Operate Point (B

)

Minimum magnetic field required to switch ON the

Hall amplifier and switching circuitry of the addressed

sensor. This circuitry is only active when the sensor is

addressed.

Magnetic Release Point (B

)

Magnetic field required to switch OFF the Hall

amplifier and switching circuitry after the output has been

switched ON. When a device is deactivated by changing

the bus address, all magnetic memory is lost.

Magnetic Hysteresis (B

HYS

)

Difference between the B

and B

magnetic field

thresholds.

FIGURE 1

BUS TIMING

SENSOR 03 — DIAGNOSTIC

AND SIGNAL CURRENTS

DIAGNOSTIC

ADDRESS 01

DIAGNOSTIC

ADDRESS 02

DIAGNOSTIC

ADDRESS 04

DIAGNOSTIC

ADDRESS

RESET

DIAGNOSTIC

ADDRESS 01

SENSOR 02 —

DIAGNOSTIC CURRENT

DIAGNOSTIC

ADDRESS 03

SENSOR 01

NOT PRESENT

RST

I QH

n • I QL

n • IQH

t phl

t plh

CLH

CHL

Dwg. WH-005

BUS

VOLTAGE

SENSOR 02

CURRENT

WITH NO

MAGNETIC

FIELD

SENSOR 03

CURRENT

WITH

MAGNETIC

FIELD

TOTAL

BUS CURRENT

WITH

MAGNETIC

FIELD AT

SENSOR 03

RESET

I QH

SENSOR 01

NOT PRESENT

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HALL-EFFECT SENSOR ICs

ofthe address cycle. This response may be

used as an indication that the sensor is "alive

and well" on the bus and is called the

diag-

nostic response. If the sensor detects an

ambient magnetic field, it continues with I

during the low portion of the address cycle.

This response from the sensor is called the

signal response. When the next positive

(address) transition is detected, the sensor

becomes disabled, and its contribution to the

bus signal current returns to I

Bus Current

Figure 1 shows the addressing protocol.

The top trace represents the bus voltage

transitions as controlled by the bus driver

(see Applications Notes for an optimal bus

driver schematic). The second trace repre-

sents the bus current contribution of Sensor

02. The

diagnostic response from the sensor

indicates that it detected its address on the

bus. However, no

signal current is shown,

which indicates that sufficient magnetic field

is not detected at the chip surface and that

pin 3 is open circuited. The third trace

represents the current drain of Sensor 03

when a magnetic field is detected. Note both

the

diagnostic and signal currents from the

sensor. The last trace represents the overall

bus current drain. When no sensors are

addressed, the net bus current is the sum of

quiescent currents of all sensors on the bus

(for 'n' sensors, the bus current drain is

n • I

Bus Issues

After a reset, while at the address LOW

voltage (VL), and before the first address

pulse, bus current calibration may be per-

formed. This feature allows for fail-safe

detection of signal current and eliminates

detection problems caused by low signal

current (I

), the operation of sensors at

various ambient temperatures, lot-to-lot

variation of quiescent current, and the

addition or replacement of sensors to the bus

while in the field. At present, a maximum of

30 active sensors can coexist on the same

bus, each with a different address. Address

TYPICAL DEVICE QUIESCENT CURRENT

FIGURE 2

SENSOR CONNECTIONS

Dwg. EH-004

SWITCH

POSITIVE BUS SUPPLY

BUS RETURN

SUPPLY VOLTAGE, V IN VOLTS

Dwg. GH-045

QUIESCENT CURRENT, I IN mA

0.5

1.0

1.5

2.0

T = +25

BUS

3054

MULTIPLEXED

TWO-WIRE

HALL-EFFECT SENSOR ICs

115 Northeast Cutoff, Box 15036

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

ADDRESS

RESET

ANALOG OUT

(POSITIVE) BUS SUPPLY

BUS RETURN

MICROPROCESSOR

INTERFACE

Dwg. EH-005

31 is designed to be inactive to allow for

further address expansion of the bus (to 62

maximum addresses). In order to repeat the

address cycle, the bus must be reset, as

shown in Figure 1, by bringing the supply

voltage to below V

RST

. Sensors have been

designed not to ‘wrap-around’.

Magnetic Sensing

The sensor IC has been designed to

respond to an external magnetic field whose

magnetic strength is greater than B

. It

accomplishes this by amplifying the output of

an on-chip Hall transducer and applying it to

a threshold detector. In order that bus

current is kept to a minimum, the transducer

and amplification circuitry is kept powered

down until the sensor is addressed. Hence,

the magnetic status is evaluated only when

the sensor is addressed.

External Switch Sensing

Pin 3 of the IC may be used to detect the

status of an external switch when magnetic

field sensing is not desired (and in the

absence of a magnetic field). The allowable

states for the switch are ‘open’ or ‘closed’

(shorted to sensor ground).

APPLICATIONS NOTES

Magnetic Actuation

The left side of Figure 2 shows the wiring of an A3054KU or

A3054SU when used as a magnetic threshold detector. Pin 1 of the

sensor is wired to the positive terminal of the bus, pin 2 is connected to

the bus negative terminal, and

pin 3 has no connection.

Mechanical Actuation

The right side of Figure 2 shows the wiring of an A3054KU or

A3054SU when used to detect the status of a mechanical switch.

In this case, pin 3 is connected to the switch. The other side of the

switch is connected to the bus return (negative bus supply or ground).

When the mechanical switch is closed, and the correct bus address is

detected by the IC, the sensor responds with a signal current. If the

switch is open, only the diagnostic current is returned.

Bus Configuration

A maximum of 30 individually addresable sensors may be con-

nected across the same two-wire bus as shown in Figure 3. It is

recommended that the sensors use a dedicated digital ground wire to

minimize the effects of changing ground potential (as in the case of

chassis ground in the automotive industry).

The bus was not designed to require two-wire twisted pair wiring to

the sensors. However, in areas of extreme electromagnetic interfer-

ence, it may be advisable to install a small bypass capacitor (0.01

for example) between the supply and ground terminals of each sensor

instead of using the more expensive wiring.

FIGURE 3

BUS INTERCONNECTION

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HALL-EFFECT SENSOR ICs

Bus Driver

It is recommended that the bus be controlled

by microprocessor-based hardware for the

following reasons:

• Sensor address information may be stored

in ROM in the form of a look-up table.

• Bus faults can be pinpointed by the

microprocessor by comparing the diagnos-

tic response to the expected response in

the ROM look-up table.

• The microprocessor, along with an A/D

converter, can also be used to self cali-

brate the quiescent currents in the bus and

hence be able to easily detect a signal

response.

• The microprocessor can also be used to filter out random line noise

by digitally filtering the bus responses.

• The microprocessor can easily keep track of the signal responses

and initiate the appropriate action (e.g., light a lamp or sound an

alarm, and also pinpoint the location of the signal).

Optimally, the microprocessor is used to control bus-driving

circuitry that will accept TTL-level inputs to drive the bus and will return

an analog voltage representation of the bus current.

Interface Schematic

The bus driver is easily designed using a few operational amplifi-

ers, resistors, and transistors. Figure 4 shows a schematic of a

recommended bus driver circuit that is capable of providing 6 V to 9 V

transitions, resetting the bus, and providing an analog measurement of

the bus current for the A/D input of the microprocessor.

FIGURE 4

BUS INTERFACE SCHEMATIC

50 k

Ω

Dwg. EH-003A

+15 V

1 k

Ω

10 k

Ω

9 V

20 k

Ω

5 k

Ω

5 k

Ω

ADDRESS

RESET

1 k

Ω

50 k

Ω

100 k

Ω

100 k

Ω

SWITCH

BUS SUPPLY

BUS RETURN

ANALOG OUT

0.001

3054

MULTIPLEXED

TWO-WIRE

HALL-EFFECT SENSOR ICs

115 Northeast Cutoff, Box 15036

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

In Figure 4, the ADDRESS input provides a TTL-compatible input

to control the bus supply. A HIGH (5 V) input switches Q

ON and sets

the bus voltage to 6 V through the resistor divider R

, R

, and Zener

. A LOW input switches Q

OFF and sets the bus voltage to 9 V

). This voltage is fed into the positive input of the operational

amplifier OP

and is buffered and made available at BUS SUPPLY (or

sensor supply). Bus reset control is also available in the form of a TTL-

compatible input. When the RESET input is HIGH, Q

is switched ON

and the positive input of the operational amplifier is set to the satura-

tion voltage of the transistor (approximately 0 V). This resets the bus.

A linear reading of the bus current is made possible by amplifying

the voltage generated across R

(which is I

BUS

• R

). The amplifier,

, is a standard differential amplifier of gain R

(provided that R

= R

, R

= R

). The gain of the total transim-pedance amplifier is

given by:

OUT

= I

BUS

• R

This voltage is available at the ANALOG OUT terminal.

Bus Control Software

The processing of the bus current (available at ANALOG OUT) is

best done by feeding it into the A/D input of a microprocessor. If the

flexibility provided by a microprocessor is not desired, this signal could

be fed into threshold detection circuitry; e.g., comparator, and the

output used to drive a display.

Related References

1. G. AVERY, “Two-Terminal Hall Sensor,”

ASSIGNEE: Sprague

Electric Company, North Adams, MA, United States. Patent number

4,374,333; Feb. 1983.

2. T. WROBLEWSKI and F. MEISTERFIELD, “Switch Status

Monitoring System, Single-Wire Bus, Smart Sensor Arrangement

There Of,”

ASSIGNEE: Chrysler Motor Corporation, Highland Park, Ml,

United States. Patent number 4,677,308; June 1987.

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Dimensions in Inches

(controlling dimensions)

Dimensions in Millimeters

(for reference only)

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.

4. Recommended minimum PWB hole diameter to clear transition area is

0.035” (0.89 mm).

5. Where no tolerance is specified, dimension is nominal.

6. Minimum lead length was 0.500” (12.70 mm). If existing product to the

original specifications is not acceptable, contact sales office before

ordering.

Dwg. MH-003D mm

1.60

1.50

0.46

0.38

0.41

1.27

2.54

SEE NOTE

4.65

4.52

4.60

4.47

15.24

14.23

2.18

MAX

Dwg. MH-003D in

0.063

0.059

0.018

0.015

0.016

0.050

0.100

SEE NOTE

0.183

0.178

0.181

0.176

0.600

0.560

0.086

MAX

3054

MULTIPLEXED

TWO-WIRE

HALL-EFFECT SENSOR ICs

115 Northeast Cutoff, Box 15036

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

HALL-EFFECT SENSORS SELECTION GUIDE

Partial Part

Avail. Oper.

Operate Limits Over Temp.

Number

Temp.

BOP max

BRP min

Bhys min

Function†

Notes

3046

E/L

+200

-200

Gear-Tooth Sensor

3054

K/S

+300

5.0

Unipolar Multiplex

3056

E/L

+225

-225

Gear-Tooth Sensor

3058

E/L

+300

-300

150

Gear-Tooth Sensor

3059

K/S

+100

-100

AC Gear-Tooth Sensor

3060

K/S

+35

-35

AC Gear-Tooth Sensor

3121

E/L

+500

+80

Unipolar Switch

3122

E/L

+430

+120

Unipolar Switch

3123

E/L

+470

+160

Unipolar Switch

3132

K/L/S

+95

-95

Bipolar Switch

3133

K/L/S

+75

-75