3055 Datasheet, PDF (3/8 Pages) Allegro MicroSystems – MULTIPLEXED TWO-WIRE HALL-EFFECT SENSOR ICs

3055
MULTIPLEXED
TWO-WIRE HALL EFFECT
SENSOR IC
SENSOR LOCATION
(±0.005” [0.13 mm] die placement)
ACTIVE AREA DEPTH
0.015"
0.38 mm
NOM
0.071"
1.80 mm
0.084"
2.13 mm
A
FUNCTIONAL BLOCK DIAGRAM
1 _BUS
COMP
REG
COMP
CLOCK
CMOS LOGIC
RESET
3
SWITCH IN
(OPTIONAL)
BRANDED
SURFACE 1
2
3
Dwg. MH-002A
DEFINITION OF TERMS
2 GROUND
Dwg. FH-009
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_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, which
monitors the supply voltage, V_BUS.
HlGH-to-LOW Threshold (V_HL)
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_H)
Bus HIGH voltage required for addressing. Voltage
should be greater than V_CLH.
Address LOW Voltage (V_L)
Bus LOW Voltage required for addressing. Voltage
should be greater than V_RST and less than V_CHL.
Bus Reset Voltage (V_RST)
Voltage level required to reset individual sensors.
Sensor Quiescent Current Drain (I_Q)
The current drain of bus sensors when active but not
addressed. I_QH is the maximum quiescent current drain
when the sensor is not addressed and is at V_H. I_QL is the
maximum quiescent current drain when the sensor is not
addressed and is at V_L.
Diagnostic Phase
Period on the bus when the address voltage is at V_H.
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_L. During
this period, a correctly addressed sensor that detects a
magnetic field greater than magnetic Operate Point, B_OP,
responds by maintaining a current drain of I_S on the bus.
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_S)
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_OP)
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_RP)
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_HYS)
Difference between the B_OP and B_RP magnetic field thresh-
olds.