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3054 MULTIPLEXED TWO-WIRE HALL-EFFECT SENSOR ICs
3054
MULTIPLEXED TWO-WIRE HALL-EFFECT SENSOR ICs
The A3054KU and A3054SU Hall-effect sensors are digital magnetic sensing ICs capable of communicating over a two-wire power/ signal bus. Using a sequential addressing scheme, the device responds 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 switching 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 magneticfield or switch-status sensing, low-noise amplification of the Halltransducer output, and high-density decoding and control logic is made possible by the development of a new sensor DABiCTM (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 temperature ranges; the A3054SU operates within specifications between -20C and +85C, while the A3054KU is rated for operation between -40C and +125C. Alternative magnetic and temperature specifications 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).
Data Sheet 27680.1
LOGIC
1
2
GROUND
BUS
Dwg. PH-005
Pinning is shown viewed from branded side.
SWITCH IN
ABSOLUTE MAXIMUM RATINGS
at TA = +25C
Supply Voltage, V BUS . . . . . . . . . . . . . . 18 V Magnetic Flux Density, B . . . . . . . Unlimited Operating Temperature Range, TA A3054KU . . . . . . . . . . . -40C to +125C A3054SU . . . . . . . . . . . . -20C to +85C Storage Temperature Range, TS . . . . . . . . . . . . . . . . . -55C to +150C Package Power Dissipation, PD . . . . . . . . . . . . . . . . . . . . . . . 635 mW
X
3
FEATURES
s s s s s s s 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 A3054KU-XX A3054SU-XX Operating Temperature Range -40C to +125C -20C to +85C
where XX = address (01, 02, ... 29, 30).
3054 MULTIPLEXED TWO-WIRE HALL-EFFECT SENSOR ICs
ELECTRICAL CHARACTERISTICS over operating temperature range.
Limits Characteristic Power Supply Voltage Signal Current Quiescent Current Symbol VBUS IS IQL IQH IQ Address Range Clock Thresholds Addr VCLH VCHL VCHYS Max. Clock Frequency* Address LOW Voltage Address HIGH Voltage Reset Voltage Propagation Delay* fCLK VL VH VRST tplh tphl Pin 3-2 Resistance RSWH RSWL Pin 3-2 Output Voltage VSWH VSWL LOW to HIGH HIGH to LOW DUT Addressed, B < 5 G DUT Addressed, B > 300 G DUT Addressed, B < 5 G DUT Addressed, B> 300 G DUT Addressed, B > 300 G VBUS = 6 V VBUS = 9 V IQL - IQH Factory Specified LOW to HIGH HIGH to LOW Hysteresis 50% Duty Cycle Test Conditions Min -- 12 -- -- -- 1 -- 6.5 -- 2.5 VRST VCLH 2.5 10 -- -- -- -- -- Typ -- 15 1.5 1.4 100 -- -- -- 0.8 -- 6.0 9.0 3.5 20 5.0 50 200 3.9 30 Max 15 20 2.5 2.5 300 30 8.5 -- -- -- VCHL VBUS 5.5 30 10 -- -- -- -- Units V mA mA mA A -- V V V kHz V V V s s k V mV
MAGNETIC CHARACTERISTICS over operating temperature range.
Limits Characteristic Magnetic Threshold Symbol BOP BRP Hysteresis BHYS Test Conditions Turn-On Turn-Off BOP - BRP Min. 50 5.0 5.0 Typ. 150 100 50 Max. 300 295 -- Units G G G
Typical Data is at TA = +25C 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.
115 Northeast Cutoff, Box 15036 W Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright (c) 1995 Allegro MicroSystems, Inc.
3054 MULTIPLEXED TWO-WIRE HALL-EFFECT SENSOR ICs
SENSOR LOCATION
(0.005" [0.13 mm] die placement)
ACTIVE AREA DEPTH 0.015" 0.38 mm NOM 0.090" 2.29 mm
FUNCTIONAL BLOCK DIAGRAM
1
BUS
REG
0.073" 1.85 mm
COMP
COMP
CLOCK
CMOS LOGIC
RESET
A
BRANDED SURFACE 1 2 3
3
SWITCH IN (OPTIONAL)
2
Dwg. MH-002-10A
GROUND
Dwg. FH-009
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 (VCLH) 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, VBUS. HlGH-to-LOW Threshold (VHL) 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, VBUS. Bus HIGH Voltage (VH) Bus HIGH voltage during addressing. Voltage should be greater than VCLH. Address LOW Voltage (VL) Bus LOW voltage during addressing. Voltage should be greater than VRST and less than VCHL . Bus Reset Voltage (VRST) Voltage level while resetting sensors. Sensor Quiescent Current Drain (IQ) The current drain of bus sensors when active but not addressed. IQH is the quiescent current drain when the sensor is not addressed and is at VH IQL is the quiescent current drain when the sensor is not addressed and is at VL. Note that IQL is greater than IQH . Diagnostic Phase Period on the bus when the address voltage is at VH . 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 VL. During this period, a correctly addressed sensor that detects a magnetic field greater than the magnetic operate point, BOP , responds by maintaining a current drain of IS 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 (IS ) 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
ADDRESSING PROTOCOL
Magnetic Operate Point (BOP ) 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 (BRP) 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 (BHYS) Difference between the BOP and B RP magnetic field thresholds. 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 (VL) and the bus quiescent current is measured. The bus is then toggled between VL and V H (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 ( IS) during the next HIGH portion
FIGURE 1
BUS TIMING
V H V CLH
DIAGNOSTIC ADDRESS 01
DIAGNOSTIC ADDRESS 02
DIAGNOSTIC ADDRESS 03
DIAGNOSTIC ADDRESS 04
DIAGNOSTIC ADDRESS n
DIAGNOSTIC ADDRESS 01
BUS VOLTAGE
V CHL V L
RESET
V RST 0 t plh t phl
RESET
IS
SENSOR 02 -- DIAGNOSTIC CURRENT
SENSOR 02 CURRENT WITH NO MAGNETIC FIELD
I QL I QH 0
IS
SENSOR 03 -- DIAGNOSTIC AND SIGNAL CURRENTS
SENSOR 03 CURRENT WITH MAGNETIC FIELD
I QL I QH 0
I
S
TOTAL BUS CURRENT WITH MAGNETIC FIELD AT SENSOR 03
SENSOR 01 NOT PRESENT
n * I QL n * I QH 0
SENSOR 01 NOT PRESENT
Dwg. WH-005
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
3054 MULTIPLEXED TWO-WIRE 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 diagnostic response. If the sensor detects an ambient magnetic field, it continues with IS 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 IQ. 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 represents 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 * IQ). Bus Issues After a reset, while at the address LOW voltage (VL), and before the first address pulse, bus current calibration may be performed. This feature allows for fail-safe detection of signal current and eliminates detection problems caused by low signal current (IS), 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
2.0
IN Q mA QUIESCENT CURRENT, I
1.5
1.0
T A = +25C
0.5
0 0 3 6 9 12 15
SUPPLY VOLTAGE, V
IN BUS VOLTS
Dwg. GH-045
FIGURE 2
SENSOR CONNECTIONS
POSITIVE BUS SUPPLY
X
X
1
2
3
1
2
3
NC SWITCH
BUS RETURN
Dwg. EH-004
3054 MULTIPLEXED TWO-WIRE HALL-EFFECT SENSOR ICs
FIGURE 3
BUS INTERCONNECTION
MICROPROCESSOR
ADDRESS INTERFACE
(POSITIVE) BUS SUPPLY
RESET
01
02
28
29
30
ANALOG OUT
BUS RETURN
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 VRST. 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 BOP. 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 connected 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 interference, it may be advisable to install a small bypass capacitor (0.01 F for example) between the supply and ground terminals of each sensor instead of using the more expensive wiring.
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
3054 MULTIPLEXED TWO-WIRE 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 diagnostic 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 calibrate 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 amplifiers, 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
+15 V
1 k 10 k R 4 9V Z1 0.001 F 20 k R5 ADDRESS 5 k Q1 RESET 5 k 50 k R8 50 k R7
1 2 3 1 2 3
1 k Q3 OP 1 BUS SUPPLY 50 R 6 Q2
X
X
NC SWITCH
100 k R 9
BUS RETURN
ANALOG OUT OP 2 100 k R 10
Dwg. EH-003A
3054 MULTIPLEXED TWO-WIRE HALL-EFFECT SENSOR ICs
In Figure 4, the ADDRESS input provides a TTL-compatible input to control the bus supply. A HIGH (5 V) input switches Q1 ON and sets the bus voltage to 6 V through the resistor divider R4, R5, and Zener Z1. A LOW input switches Q1 OFF and sets the bus voltage to 9 V (Z1). This voltage is fed into the positive input of the operational amplifier OP1 and is buffered and made available at BUS SUPPLY (or sensor supply). Bus reset control is also available in the form of a TTLcompatible input. When the RESET input is HIGH, Q2 is switched ON and the positive input of the operational amplifier is set to the saturation 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 R6 (which is IBUS * R6). The amplifier, OP2, is a standard differential amplifier of gain R9/R7 (provided that R7 = R8, R9 = R10). The gain of the total transim-pedance amplifier is given by: VOUT = IBUS * R6 * R9/R 7 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.
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
3054 MULTIPLEXED TWO-WIRE HALL-EFFECT SENSOR ICs
Dimensions in Inches
(controlling dimensions)
Dimensions in Millimeters
(for reference only)
0.183 0.178 0.063 0.059
4.65 4.52 1.60 1.50
0.181 0.176 45 0.086
MAX
4.60 4.47 45 2.18
MAX
1
2
3
0.018
1
2
3
0.46
0.600 0.560 0.016
SEE NOTE
0.015
15.24 14.23 0.41
SEE NOTE
0.38
0.050 0.100
Dwg. MH-003D in
1.27 2.54
Dwg. MH-003D mm
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.
3054 MULTIPLEXED TWO-WIRE HALL-EFFECT SENSOR ICs
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115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
3054 MULTIPLEXED TWO-WIRE HALL-EFFECT SENSOR ICs
Allegro MicroSystems, Inc. reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the design of its products. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use.
3054 MULTIPLEXED TWO-WIRE HALL-EFFECT SENSOR ICs
HALL-EFFECT SENSORS SELECTION GUIDE
Partial Part Number 3046 3054 3056 3058 3059 3060 3121 3122 3123 3132 3133 3134 3141 3142 3143 3144 3161 3175 3177 3185 3187 3188 3189 3195 3197 3235 3275 3421 3422 3503 3515 3516 3517 3518 3625 3626 5140 Avail. Oper. Temp. E/L K/S E/L E/L K/S K/S E/L E/L E/L K/L/S K/L/S E/L E/L E/L E/L E/L E S S E/L E/L E/L E/L E/L L S S E/L E/L S E/L E/L L/S L/S S S E Operate Limits Over Temp. BOP max BRP min Bhys min +200 -200 +300 +5 +225 -225 +300 -300 +100 -100 +35 -35 +500 +80 +430 +120 +470 +160 +95 -95 +75 -75 +50 -40 +175 +10 +245 +60 +355 +150 +450 +25 +160 +30 +180 -180 +150 -150 +300 -300 +175 -175 +200 -200 +250 -250 +200 -200 +200 -200 +200 +15 -200 -15 +250 -250 +300 -300 +85 -85 Typ. 1.3 mV/G Typ. 5.0 mV/G Typ. 2.5 mV/G Typ. 5.0 mV/G Typ. 2.5 mV/G +150 -150 +150 -150 +240 +25 15 5.0 15 150 20 10 60 70 70 30 30 10 20 30 30 20 5.0 80 50 280 100 160 100 110 110 15 15 100 240 10 - - - - - 200* 200* 20 Function Notes Gear-Tooth Sensor Unipolar Multiplex 1 Gear-Tooth Sensor Gear-Tooth Sensor AC Gear-Tooth Sensor AC Gear-Tooth Sensor Unipolar Switch Unipolar Switch Unipolar Switch Bipolar Switch Bipolar Switch Bipolar Switch Unipolar Switch Unipolar Switch Unipolar Switch Unipolar Switch 2-Wire Unipolar Switch Bipolar Latch Bipolar Latch Bipolar Latch Bipolar Latch Bipolar Latch Bipolar Latch Bipolar Latch 2, 3 Bipolar Latch 3 Unipolar Switch 4 Unipolar Switch Bipolar Latch 5 Direction Detection Direction Detection Linear Sensor Chopper-Stabilized Linear Sensor Chopper-Stabilized Linear Sensor Chopper-Stabilized Linear Sensor Chopper-Stabilized Linear Sensor 900 mA Bipolar Latch 3, 5, 6 400 mA Bipolar Latch 3, 5, 6 300 mA Unipolar Switch 3, 6
Operating Temperature Ranges: C = 0C to +70C, S = -20C to +85C, E = -40C to +85C, K = -40C to +125C, L = -40C to +150C Notes 1. Multiplexed two-wire sensor; after proper address, power/signal bus current indicates magnetic field condition. 2. Active pull down. 3. Protected. 4. Output 1 switches on south pole, output 2 switches on north pole for 2-phase, bifilar-wound, unipolar-driven brushless dc motor control. 5. Complementary outputs for 2-phase bifilar-wound, unipolar-driven brushless dc motor control. 6. Power driver output. * Typical. Latches will not switch on removal of magnetic field; bipolar switches may switch on removal of field but require field reversal for reliable operation over operating temperature range.
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000

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