3055

MULTIPLEXED

TWO-WIRE HALL EFFECT

SENSOR IC

FUNCTIONAL BLOCK DIAGRAM

SENSOR LOCATION

(±0.005” [0.13 mm] die placement)

A

1

3

2

Dwg. MH-002A

0.015"

0.38 mm

NOM

0.071"

1.80 mm

0.084"

2.13 mm

BRANDED

SURFACE

ACTIVE AREA DEPTH

CLOCK

Dwg. FH-009

BUS

SWITCH IN

(OPTIONAL)

GROUND

CMOS LOGIC

REG

COMP

COMP

RESET

1

3

2

DEFINITION OF TERMS

Sensor Address

Each bus sensor has a factory-specified predefined

address. At present, allowable sensor addresses are

integers from 1 to 30.

LOW-to-HlGH Clock Threshold (V

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, which

monitors the supply voltage, V

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, which monitors the supply voltage, V

BUS.

Bus HIGH Voltage (V

Bus HIGH voltage required for addressing. Voltage

should be greater than V

Address LOW Voltage (V

Bus LOW Voltage required for addressing. Voltage

should be greater than V

Bus Reset Voltage (V

Voltage level required to reset individual sensors.

Sensor Quiescent Current Drain (I

The current drain of bus sensors when active but not

addressed. I

when the sensor is not addressed and is at V

I

maximum quiescent current drain when the sensor is not

addressed and is at V

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

this period, a correctly addressed sensor that detects a

magnetic field greater than magnetic Operate Point, B

responds by maintaining a current drain of I

This response from the sensor is called the signal response

and the bus current

increase is called the signal current.

Sensor Address Response Current (I

Current returned by the bus sensors during the

diagnostic and

the

signal responses of the bus sensors. This is accomplished

by enabling the constant current source (CCS).

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 switched ON.

This is due to magnetic memory in the switching circuitry.

However, when a device is deactivated by changing the

current bus address, all magnetic memory is lost.

Magnetic Hysteresis (B

Difference between the B

olds.