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Part: A3507
Category:
Analog & Mixed-Signal Processing
Description:
Company: Allegro Micro Systems, Inc.
Datasheet: Download A3507 datasheet File size : 867 kB
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3507 3508
AND
RATIOMETRIC, LINEAR HALL-EFFECT SENSORS FOR HIGH-TEMPERATURE OPERATION
The A3507 and A3508 are sensitive, temperature-stable linear Hall-effect sensors. Ratiometric, linear Hall-effect sensors provide a voltage output that is proportional to the applied magnetic field and have a quiescent output voltage that is approximately 50% of the supply voltage. These magnetic sensors are ideal for use in linear and rotary position sensing systems in the harsh environments of automotive and industrial applications over extended temperatures to -40°C and +150°C. The two devices are similar except for temperature stability over the operating temperature range. See the Magnetic Characteristics table for complete, individual device parametrics. Each monolithic circuit integrates a quadratic Hall element, improved temperature compensating circuitry to reduce the intrinsic sensitivity drift of the Hall element, a small-signal high-gain amplifier, and a rail-to-rail low-impedance output stage. Many problems normally associated with low-level analog signals are minimized by having the Hall element and amplifier in a single chip. Output precision is obtained by internal gain and offset trim adjustments during the manufacturing process. The first character of the part number suffix determines the device operating temperature range: suffix `S' is for -20°C to +85°C, suffix `E' is for -40°C to +85°C, and suffix `L' is for -40°C to +150°C. These devices are supplied in a 3-pin ultra-mini-SIP `UA' package.
Pinning is shown viewed from branded side.
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC . . . . . . . . . . . . 6.0 V Output Voltage, VO . . . . . . . . . . . . . 6.0 V Output Sink Current, IO . . . . . . . . 5.0 mA Magnetic Flux Density, B . . . . Unlimited Package Power Dissipation, PD . . . . . . . . . . . . . . . . . . . . See Graph Operating Temperature Range, TA Suffix `S' . . . . . . . . . . . . -20°C to +85°C Suffix `E' . . . . . . . . . . . . -40°C to +85°C Suffix `L' . . . . . . . . . . . -40°C to +150°C Storage Temperature Range, TS . . . . . . . . . . . . . . . -65°C to +170°C
T C. UY DL ON RO PE DC EN UE IN ER TF NE OR CR IS O DF --
V
CC
Data Sheet 27501.1C
1
X
2
3
GROUND
Dwg. PH-006
OUTPUT
SUPPLY
FEATURES
s Output Voltage Proportional to Applied Magnetic Field s Ratiometric Rail-to-Rail Output s Improved Sensitivity s Superior Temperature Stability s 4.5 V to 5.5 V Operation s Small Package Size s Solid-State Reliability
Always order by complete part number, e.g., A3507EUA .
3507 AND 3508 RATIOMETRIC, LINEAR HALL-EFFECT SENSORS FOR HIGH-TEMP. OPERATION
FUNCTIONAL BLOCK DIAGRAM
ALLOWABLE PACKAGE POWER DISSIPATION in MILLIWATTS
700
600
1 VCC
"U" PACKAGE RJA = 183°C/W
500
400
300 "UA" PACKAGE RJA = 206°C/W 200
X
3
OUTPUT
2 GROUND
100
Dwg. FH-011
0 20 40 60 100 80 AMBIENT TEMPERATURE in ° C 120 140 160
Dwg. GH-046A
noted).
ELECTRICAL CHARACTERISTICS over operating temperature range, at VCC = 5 V (unless otherwise
Limits Characteristic Supply Voltage Supply Current Quiescent Voltage Output Output Voltage Symbol V CC I CC V OQ VOH V OL Bandwidth (-3 dB) Output Resistance Wide-Band Output Noise BW rO eo B = 0, BW = 10 Hz to 10 kHz, TA = 25°C Test Conditions Operating B = 0, VCC = 5.5 V, IO = 0 B = 0, IO = 1 mA, TA = 25°C B = 0, IO = 1 mA B = +X*, IO = 1 mA B = -X*, IO = -1 mA Min. 4.5 2.0 1.8 4.5 20 Typ. 5.0 2.5 2.5 4.8 0.2 2.5 125 Max. 5.5 10 3.0 3.2 0.5 10 Units V mA V V V V kHz µV
Negative current is defined as coming out of (sourcing) the output. * This test requires positive and negative fields sufficient to swing the output driver between fully OFF and saturated (ON), respectively. It is NOT intended to indicate a range of linear operation.
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright © 1994, 2001, Allegro MicroSystems, Inc.
3507 AND 3508 RATIOMETRIC, LINEAR HALL-EFFECT SENSORS FOR HIGH-TEMP. OPERATION
MAGNETIC CHARACTERISTICS over operating temperature range, at VCC = 5 V, IO = 1 mA
(unless otherwise noted). Part Numbers A3507LUA Characteristic* Operating Temp. Range, TA Sensitivity at TA = 25°C over Oper. Temp. Range Sens(T) at TA = Max.
A3507EUA Min. -40 2.0 1.7 -6.3 -8.8 Typ. 2.5 2.5 1.2 -1.3 100 100 100 100 100 Max. +85 3.0 3.3 8.7 6.2 ±3 5 Min. -20 2.0 1.7 -10 -10
A3508SUA Typ. 2.5 2.5 100 100 100 100 100 Max. +85 3.0 3.3 10 10 ±5 0 Units °C mV/G mV/G % % G % % % % %
Min. -40 2.0 1.7 -5.0 -8.8
Typ. 2.5 2.5 2.5 -1.3 100 100 100 100 100
Max. +150 3.0 3.3 10 6.2 ±3 5
at TA = Min. VOQ(T)
Ratiometry, VOQ(V) Ratiometry, Sens(V) Positive Linearity, Lin+ Negative Linearity, Lin Symmetry
Magnetic flux density is measured at most sensitive area of device located 0.018" (0.46 mm) below the branded face of the "UA" package. * See Characteristics Definitions for test conditions. The nominal sensitivity temperature stability is designed to compensate for the temperature coefficient of samarium-cobalt magnets (-0.02%/°C). This calculation (formula 1, next page) yields the device's equivalent accuracy, over the operating temperature range, in gauss.
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3507 AND 3508 RATIOMETRIC, LINEAR HALL-EFFECT SENSORS FOR HIGH-TEMP. OPERATION
CHARACTERISTICS DEFINITIONS
Quiescent Voltage Output. In the quiescent state (no magnetic field), the output is ideally equal to one-half of the supply voltage over the operating voltage and temperature range (VOQ VCC/2). Due to internal component tolerances and thermal considerations, there is a tolerance on the quiescent voltage output and on the quiescent voltage output as a function of supply voltage and ambient temperature. For purposes of specification, the quiescent voltage output as a function of temperature is defined as VOQ(T) = VOQ(TA) VOQ(25°C) Sens(25°C) Ratiometry. The A3507 and A3508 feature a ratiometric output. The quiescent voltage output and sensitivity are proportional to the supply voltage (ratiometric). The per cent ratiometric change in the quiescent voltage output is defined as VOQ(V) = VOQ(VCC) / VOQ(5V) VCC / 5 V
x 100%
(4)
(1)
and the per cent ratiometric change in sensitivity is defined as Sens(V) = Sens(VCC) / Sens(5V) VCC / 5 V
This calculation yields the device's equivalent accuracy, over the operating temperature range, in gauss. Sensitivity. The presence of a south-pole magnetic field perpendicular to the package face (the branded surface) will increase the output voltage from its quiescent value toward the supply voltage rail by an amount proportional to the magnetic field applied. Conversely, the application of a north pole will decrease the output voltage from its quiescent value. This proportionality is specified as the sensitivity of the device and is defined as V O(500G) VO(-500G) 1000 G
x 100%
(5)
Linearity and Symmetry. The on-chip output stage is designed to provide a linear output to within 500 mV of either rail with a supply voltage of 5 V. This is equivalent to approximately ±800 gauss of ambient field. Although application of stronger magnetic fields will not damage these devices, it will force the output into a non-linear region. Linearity in per cent is measured and defined as VO ( 5 0 0 G ) V O Q 2 (VO(250G) VOQ) V O(-500G) VOQ 2 (VO(-250G) VOQ)
Lin+ = (2)
x 100%
(6)
Sens =
The stability of sensitivity as a function of temperature is defined as Sens(T) = Sens(TA) Sens(25°C) Sens(25°C)
Lin =
x 100%
(7)
and output symmetry as x 100% (3) Sym = V O(500G) V OQ VOQ VO(-500G) x 100% (8)
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
3507 AND 3508 RATIOMETRIC, LINEAR HALL-EFFECT SENSORS FOR HIGH-TEMP. OPERATION
APPLICATIONS INFORMATION
Calibrated linear Hall devices, which can be used to determine the actual flux density presented to the sensor in a particular application, are available. For safe, reliable operation, the output should not be pulled above the supply voltage or pulled below the device ground. For optimum performance, a 100 pF capacitor between the output and ground should be added. The nominal sensitivity is factory set to compensate for the temperature coefficient of samarium-cobalt magnets ( - 0 . 0 2 % /° C ) . The ratiometric feature is especially valuable when these devices are used with an analog-to-digital converter. A/D converters typically derive their LSB step size by ratioing off a reference voltage line. If the reference voltage varies, the LSB will vary proportionally. This is a major error source in many sensing systems. The A3507/08 can eliminate this source of error by their ratiometric operation. Because their gain and offsets are proportional to the supply voltage, if they are powered from the A/D reference voltage, the sensor output voltage will track changes in the LSB value. Hall-effect applications information is available in the application note "Linear Hall-Effect Sensors" (AN 27702), which can be found in the latest issue of Allegro Electronic Data Book, AMS-702, or at
BRANDED SURFACE
SENSOR LOCATION
ACTIVE AREA DEPTH 0.0195" 0.50 mm NOM
0.082" 2.07 mm
0.055" 1.40 mm
A
1 2 3
Dwg. MH-011-6B
TYPICAL CURRENT-SENSING APPLICATION
B N x 6.9 G/A
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Dwg. AH-005A
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Others parts begin by a3
A3-1 A3-2 A3-3 A3-4
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