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Part: 3055
Category:
Automotive
-> Sensor Interface
Description: Multiplexed Two-wire Hall-effect Sensor Ics
Company: Allegro Micro Systems, Inc.
Datasheet: Download 3055 datasheet File size : 2164 kB
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3055 MULTIPLEXED TWO-WIRE HALL EFFECT SENSOR IC
DISCONTINUED PRODUCT Shown for Reference Only
3055
MULTIPLEXED TWO-WIRE HALL - EFFECT SENSOR ICs
The UGN3055U Hall-effect sensor is a digital magnetic sensing IC 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. The device consists of high-resolution bipolar Hall-effect switching circuitry, the output of which drives high-density CMOS logic stages. These 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 BiMOS fabrication technology. This unique magnetic sensing IC operates within specifications between -20°C and +85°C. Alternate magnetic and temperature specifications are available upon request. It is supplied in a 60 mil (1.54 mm) thick, three-pin plastic SIP. Each package is clearly marked with a two-digit decimal device address (xx).
Data Sheet 27680
LOGIC
1
2
GROUND
BUS
Dwg. PH-005
SWITCH IN
Pinning is shown viewed from branded side.
ABSOLUTE MAXIMUM RATINGS at TA = +25°C
Supply Voltage, VBUS ... 24 V Magnetic Flux Density, B ... Unlimited Operating Temperature Range, TA .. -20°C to +85°C Storage Temperature Range, TS ...... -55°C to +150°C Package Power Dissipation, PD ... 750 mW
X
3
FEATURES
s Complete Multiplexed Hall-Effect IC with Simple Sequential Addressing Protocol s Allows Power and Communication Over a Two-Wire Bus (Supply/Signal and Ground) s Up to 30 Hall-Effect Sensors Can Share a Bus s Sensor Diagnostic Capabilities s Magnetic-Field or Switch-Status Sensing s Low Power of BiMOS Technology Favors Battery-Powered and Mobile Applications s Ideal for Automotive, Consumer, and Industrial Applications
Always order by complete part number:
UGN3055U .
3055 MULTIPLEXED TWO-WIRE HALL EFFECT SENSOR IC
OPERATIONAL CHARACTERISTIC over operating temperature range.
Electrical Characteristics Power Supply Voltage Signal Current Quiescent Current VBUS = 6 V VBUS = 9 V I QHIQL Address Range Clock Thresholds LOW to HIGH HIGH to LOW Hysteresis Clock Period Address LOW Voltage Address HIGH Voltage Power-On Reset Voltage Settling Time VBUS = 9 V VBUS = 6 V Propagation Delay LOW to HIGH HIGH to LOW Pin 3 Input Resistance No Magnetic Field (VOUT = HIGH) Mag. Field Present (VOUT = LOW) Magnetic Characteristics Magnetic Thresholds *Turn-On Turn-Off Hysteresis (BOPB RP) BOP BRP BHYS 50 -25 0 150 100 50 300 300 75 G G G Limits Symbol VBUS IS IQ H IQ L IQ Addr VCLH VC H L VCHYS tC L K VL VH VRST th tl tplh tp h l ROUTH ROUTL Min. -- 12 -- -- -- 1 -- 6.5 -- 0.1 VRST VCLH 2.5 100 100 10 -- 40 -- Typ. -- 15 -- -- -- -- -- -- 0.8 1.0 6 9 3.5 -- -- -- -- -- -- Max. 15 20 2.5 2.5 300 30 8.5 -- -- -- VCHL VBUS 5.5 -- -- -- 10 75 50 Units V mA mA mA µA -- V V V ms V V V µs µs µs µs k
*Alternate magnetic switch point specifications are available on request. Please contact the factory.
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright © 1988, 1991, Allegro MicroSystems, Inc.
3055 MULTIPLEXED TWO-WIRE HALL EFFECT SENSOR IC
(± 0.005" [0.13 mm] die placement)
ACTIVE AREA DEPTH 0.015" 0.38 mm
NOM
SENSOR LOCATION
0.071" 1.80 mm
FUNCTIONAL BLOCK DIAGRAM
1
BUS
REG COMP
0.084" 2.13 mm
COMP
CLOCK
CMOS LOGIC
RESET
A
BRANDED SURFACE 1 2 3
3
SWITCH IN (OPTIONAL)
2
Dwg. MH-002A
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 1 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, which 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 onchip comparator, which monitors the supply voltage, VBUS. Bus HIGH Voltage (VH) Bus HIGH voltage required for addressing. Voltage should be greater than VCLH . Address LOW Voltage (VL) Bus LOW Voltage required for addressing. Voltage should be greater than VRST and less than VCHL. Bus Reset Voltage (VRST) Voltage level required to reset individual sensors. Sensor Quiescent Current Drain (IQ) The current drain of bus sensors when active but not addressed. IQH is the maximum quiescent current drain when the sensor is not addressed and is at VH . IQL is the maximum quiescent current drain when the sensor is not addressed and is at VL. 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 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 increase is called the signal current. Sensor Address Response Current (IS) 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 (BRP) 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 (BHYS) Difference between the BOP and BRP magnetic field thresholds.
3055 MULTIPLEXED TWO-WIRE HALL EFFECT SENSOR IC
ADDRESSING PROTOCOL The device may be addressed by modulating the supply voltage as shown in Figure 1. A preferred addressing protocol is as follows: the bus supply voltage is brought down to 0V so that all devices on the bus may be 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 VH (address HIGH voltage), with each positive transition representing an increment in the bus address. After each voltage transition, the bus current is 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 reFIGURE 1 sponds with an increase in its supply current drain (called IS during the HIGH portion of the address cycle). This response may be used as an indication that the sensor is alive and well on the bus and is also called the diagnostic response. If the sensor detects an ambient magnetic field, it also responds with IS during the low portion of the address cycle. This response from the sensor is called the signal response. When the next positive transition is detected, the sensor becomes disabled, and its contribution to the bus signal current returns to IQ. Bus Current Figure 1 displays the above described addressing protocol. The top trace represents the bus voltage transitions as controlled by the bus driver (see applications note for an optimal bus driver schematic). The second trace represents the bus current contribution of sensor (address 02). The diagnostic response from the sensor indicates that it detected its address on the bus; however, no signal response current is returned, which indicates that sufficient magnetic field is not detected at the chip surface. The third trace represents the current drain of sensor 03 when a magnetic field is detected. Note both the diagnostic and signal response from the sensor. The last trace represents
BUS TIMING D1
V H V CLH V CHL V L
DIAGNOSTIC ADDRESS 01
DIAGNOSTIC ADDRESS 02
DIAGNOSTIC ADDRESS 03
DIAGNOSTIC ADDRESS 04
DIAGNOSTIC ADDRESS n
DIAGNOSTIC ADDRESS 01
BUS VOLTAGE
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
I
SENSOR 03 -- DIAGNOSTIC AND SIGNAL CURRENTS
S
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
3055 MULTIPLEXED TWO-WIRE HALL EFFECT SENSOR IC
the overall bus current drain. When no sensors are addressed, the net bus current drain is the sum of quiescent currents of all sensors on the bus (for `n' sensors, the bus quiescent current drain is n * IQ). Bus Issues At present, a maximum of 30 active sensors can coexist on the same bus, each with a different address. Address 0 is reserved for bus current calibration in software. 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 and replacement of sensors to the bus while in the field. Address 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 feeding it into 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 The third pin of the IC (pin 3) 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' and `closed' (shorted to sensor ground). APPLICATIONS NOTES Magnetic Actuation The left side of Figure 2 shows the wiring of the UGN3055U 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 the UGN3055U when used to detect the status of a mechanical switch. In this case, pin 3 is connected to the positive terminal of the switch. The negative side of the switch is connected to the negative terminal of the bus. When the mechanical switch is closed (shorted to ground) and the correct bus address is detected by the IC, the sensor responds with a signal current. If the switch is open, only a diagnostic current is returned.
FIGURE 2
SENSOR CONNECTIONS
POSITIVE BUS SUPPLY
X
X
1
2
3
1
2
3
NC SWITCH
BUS RETURN
Dwg. EH-004
Others parts begin by 30
30-1 30-2 30-3 30-4 30-5 30-6 30-7 30-8 30-9 30-10 30-11
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