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A1373 and A1374
High Precision, Output Pin Programmable Linear Hall Effect Sensors
The A1373 and A1374 high precision linear Hall effect sensors are sensitive, temperature stable, linear devices with externally programmable features. This device family incorporates a chopper-stabilized amplifier, voltage regulator, programming logic, and an output amplifier on a single IC. The patented dynamic offset cancellation used with a chopper-stabilization technique provides extremely low offset and minimal temperature drift. A high frequency clock is used for chopping, to ensure high frequency signal processing capability. The A1373 and A1374 are ideal for use in automotive and industrial linear position-sensing applications that require increased reliability and accuracy over conventional contacting-potentiometer solutions. Key applications include: throttle position sensors, pedal position sensors, and suspension height sensors. The design and manufacturing flexibility of the A1373 and A1374 complement the Allegro linear Hall effect family of devices by offering programmable gain, quiescent offset voltage for unipolar or bipolar operation, temperature coefficient, clamps, and polarity. The device can be set up in a magnetic circuit and programmed with a train of serial pulses via the output pin. Once the right combination of gain, quiescent output voltage, and temperature coefficient has been selected, the codes can be locked for one-time programming. In this manner, manufacturing tolerances can be reduced and the assembly process can be simplified. These devices are available in the KB package, a 3-pin SIP (single inline package). The lead (Pb) free version has a 100% matte tin plated leadframe.
Package KB, 3-pin SIP
1
2
3
1. VCC 2. GND 3. VOUT (Programming)
Features and Benefits
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC .......................................... 16 V Reverse-Supply Voltage, VRCC ........................ -16 V Output Voltage1, VOUT ....................................... 16 V Reverse-Output Voltage, VROUT ..................... -0.1 V Output Current Source, IOUTSOURCE ................................... 3 mA Sink, IOUTSINK .......................................... 10 mA Operating Temperature Ambient, TA, Range E.................. -40C to 85C Ambient, TA, Range L................ -40C to 150C Maximum Junction, TJ(max)........................165C Storage Temperature, TS .................. -65C to 170C Output pin programming Field-programmable for optimal application integration Selectable coarse and fine gain and quiescent output voltage Selectable sensitivity temperature coefficient Selectable output clamp voltage level Selectable output polarity Unipolar or bipolar operation Ratiometric sensitivity, clamps, and quiescent output voltage Chopper-stabilized Hall technique Wide operating temperature range On-chip regulator for over/under voltage protection On-chip regulator provides EMI robustness
1When
blowing fuses during device programming, a voltage of 28 V may be applied to VOUT.
Wide lead-spacing with KB package
A1373-DS
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors Product Selection Guide
Part Number A1373EKB A1373EKB-T A1373EKBTI A1373EKBTI-T A1373LKB A1373LKB-T A1373LKBTI A1373LKBTI-T A1374EKB A1374EKB-T A1374EKBTI A1374EKBTI-T A1374LKB A1374LKB-T A1374LKBTI A1374LKBTI-T Pbfree - Yes - Yes - Yes - Yes - Yes - Yes - Yes - Yes Packing* Bulk, 500 pcs./bag 14.24-in. reel, 2000 pcs/reel Bulk, 500 pcs./bag 14.24-in. reel, 2000 pcs/reel Bulk, 500 pcs./bag 14.24-in. reel, 2000 pcs/reel Bulk, 500 pcs./bag 14.24-in. reel, 2000 pcs/reel Ambient, TA (C) -40 to 85
-40 to 150
-40 to 85
-40 to 150
*Contact Allegro for additional packing options
Functional Block Diagram
VCC Pin 1
Voltage Regulator To all subcircuits
Dynamic Offset Cancellation
Amp
Filter
Out
VOUT Pin 3
Hall drive circuit Gain Temperature Coefficient
Offset
Trim Control
GND Pin 2
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
2
A1373-DS
A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors
CHARACTERISTIC PARAMETERS
Characteristic Symbol Test Conditions Min. Typ. Max Units
ELECTRICAL CHARACTERISTICS over operating temperature range, VCC= 5.0 V, unless otherwise noted Operation within specification, 4.5 5.0 Supply Voltage VCC Tj < 165C Supply Current Reverse-Supply Current Power-On Time1 Chopping Frequency Internal Bandwidth ICC IRCC tPO fC BW A1373 A1374 Small signal -3 dB VCC = -16 V, TA = 25C CLOAD = 10 nF, 90% full scale VOUT - - - - - - 8.2 - - 200 2.5 20
5.5 10 16 300 - - - 16 26 10 - - - - 0.25 -
V mA mA s kHz kHz kHz mV mV nF () () V V
OUTPUT CHARACTERISTICS over operating temperature range, VCC= 5.0 V, unless otherwise noted A1373 peak-to-peak, CLOAD > 1 nF, - 6 Noise2,3 VN A1374 2.5 mV/G - 14 Output Capacitance Load Output Resistive Load Phase Shift CLOAD RLOAD VOUT(Sat)HIGH Output Voltage VOUT(Sat)LOW Output Resistance MAGNETIC CHARACTERISTICS Magnetic Slew Rate SLR V/ms / Sens - 20 ROUT A1373 A1374 Magnetic signal freq. = 100 Hz Magnetic signal freq. = 1000 Hz VOUT pin to GND pin - 4700 - - 4.65 - - - - 3 3 4.7 0.2 1.5
IOUTSINK = 1.2 mA, B(kG) > (VCC-VOUT(Q)) / Sens (mV/G) IOUTSOURCE = 1.2 mA, B(kG) < VOUT(Q) / Sens (mV/G)
-
G/s
otherwise noted
PRE-PROGRAMMING TARGET (Prior to coarse and fine trim) over operating temperature range, VCC= 5.0 V, unless Pre-Programming Quiescent Output Voltage Pre-Programming Sensitivity Pre-Programming Sensitivity Temperature Coefficient VOUT(Q)PRE SensPRE TCPRE B = 0 G, TA = 25C TA = 25C TA relative to 25C 1.62 1.05 -0.016 1.80 1.31 0.05 1.98 1.75 0.104 V mV/G %/C
INITIAL COARSE PROGRAMMING over operating temperature range, VCC= 5.0 V, unless otherwise noted VOUT(Q)INITLOW Initial Coarse Quiescent Output Voltage VOUT(Q)INITMID VOUT(Q)INITHIGH SensINITLOW Initial Coarse Sensitivity SensINITMID SensINITHIGH TA = 25C Reference VOUT(Q)PRE TA = 25C Reference SensPRE TA = 25C TA = 25C - - - - - - 0.55 -3.25 - 2.8 5.5 - - - - - - V V V mV/G mV/G mV/G
Continued on the next page...
A1373-DS
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
3
A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors
CHARACTERISTIC PARAMETERS (continued)
Characteristic Symbol Test Conditions Min. Typ. Max Units QUIESCENT OUTPUT VOLTAGE PROGRAMMING over operating temperature range, VCC= 5.0 V, unless otherwise noted VOUT(Q)LOW 0.7 - 1.9 V Quiescent Output Voltage Range VOUT(Q)MID B = 0 G, TA = 25C 2.0 - 3.2 V VOUT(Q)HIGH 3.5 - 4.5 V Average Quiescent Output Voltage StepVOUT(Q) TA = 25C 3.0 3.275 3.5 mV Step Size4,5,6 Quiescent Output Voltage Fine programming value selection 0.5 x ErrPROGVOUT(Q) - - mV StepVOUT(Q) Programming Resolution accuracy Quiescent Output Voltage Drift Over Operating Temperature Range Quiescent Output Voltage Programming Bits VOUT(Q) = VOUT(Q)LOW VOUT(Q) VOUT(Q) = VOUT(Q)MID VOUT(Q) = VOUT(Q)HIGH - VOUTCLP10HIGH 10% Output Clamp Option7 VOUTCLP10LOW VOUTCLP20HIGH 20% Output Clamp Option7 VOUTCLP20LOW Delay to Clamp tCLP Coarse (Range selection) Fine (Value selection) A1373 High-side output clamp A1374 A1373 Low-side output clamp A1374 A1373 High-side output clamp A1374 A1373 Low-side output clamp A1374 A1373 A1374 - - - - - 4.350 4.300 0.4 0.3 3.925 3.900 0.9 0.8 - - - - - 2 9 - - - - - - - - - - 40 40 55 - - 4.565 4.650 0.6 0.6 4.125 4.200 1.1 1.1 2 100 3.0 6.0 11.75 14 28 56 - - - - mV mV mV Bit Bit V V V V V V V V s s mV/G mV/G mV/G V/G V/G V/G V/G Bit Bit Bit
SENSITIVITY PROGRAMMING over operating temperature range, VCC= 5.0 V, unless otherwise noted SensLOW 1.75 - Sensitivity Range8 SensMID TA = 25C 3.5 - SensHIGH 7.0 - StepSENSLOW 6 9.5 Average Sensitivity Step Size4,5,6 StepSENSMID TA = 25C 12 18.7 StepSENSHIGH 22 37.0 Sensitivity Programming Resolution Sensitivity Programming Bits POLARITY PROGRAMMING Polarity Programming Bit - Negative Sensitivity - 1 ErrPROGSENS - Fine programming value selection accuracy Coarse (Range selection) Fine (Value selection) - - - 0.5 x
StepSENS
2 8
Continued on the next page...
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
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A1373-DS
A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors
CHARACTERISTIC PARAMETERS (continued)
Characteristic Symbol Test Conditions Min. Typ. Max Units SENSITIVITY TEMPERATURE COEFFICIENT PROGRAMMING over operating temperature range, VCC= 5.0 V, unless
otherwise noted
Sensitivity Temperature Coefficient Range
TC
Sensitivity T/C codes 0 to 11, minimum (absolute) positive temperature coefficient attainable Sensitivity T/C codes 16 to 27, minimum (absolute) negative temperature coefficient attainable
-
0.07
-
%/C
-
-0.016
-
%/C
Average Sensitivity StepTC Temperature Coefficient Step TA = 150C 4,5,6 Size Sensitivity Temperature - Coefficient Programming Bits ONE-TIME PROGRAMMING - Device Programming Lock Bit RATIOMETRY over operating temperature range, VCC= 5.0 V, unless otherwise noted RatVOUT(Q) VCC at VOPERATING Quiescent Voltage Error RatSENS Sensitivity Error VCC at VOPERATING Clamp Error RatVOUTCLP VCC at VOPERATING LINEARITY over operating temperature range, VCC= 5.0 V, unless otherwise noted Positive Linearity Error Lin+ VCC at VOPERATING Lin- Negative Linearity Error VCC at VOPERATING SYMMETRY over operating temperature range, VCC= 5.0 V, unless otherwise noted Sym Symmetry Error VCC at VOPERATING - VCC
ADDITIONAL CHARACTERISTICS Sensitivity Drift9 Sens
- -
0.01 5
1
- -
%/C
Bit
- - - - - - - -
- - - - - -
Bit % % % % % % % mA mA
0.25 1.0 1.5 0.5 0.5 0.35
- - -
-
2 18 4
FAULT CONDITIONS over operating temperature range, VCC= 5.0 V, unless otherwise noted VOUT pin to VCC pin - IOUTSHT Shorted Output Wire VOUT pin to GND pin -
1 2
tPO does not include tCLP , specified in the Quiescent Programming section of this table. Peak to peak value exceeded: 0.3% (6). 3 For A1373, no digital noise is present at the output. 4 Step size is larger than required for the specified range, to take into account manufacturing spread. 5 Individual code step sizes can be greater than 2x larger than the step size at each significant bit rollover. 6 Average fine code step size in a given range = (Output value at highest fine code in the range - Output value at code 0 of the range) / Total quantity of steps (codes) in the range. 7 Values indicated are valid if any additional magnetic field does not exceed B(kG)= 2 (V) / Sens (mv/G), after V OUTCLP is reached. 8 Program the Sensitivity T/C register before programming Sensitivity Coarse and Sensitivity Fine, due to a worst case shift of 3% in sensitivity at 25C at the maximum values for Sensitivity T/C: Positive T/C and Sensitivity T/C: Negative T/C. The Programming Guidelines section in this document lists a complete recommended order for programming individual values. 9Drift due to temperature cycling is due to package effects on the Hall transducer. The stress is reduced when the package is baked. However, it will recover over time after removal from the bake.
A1373-DS
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors
Typical Characteristics
Temperature Coefficient Code Profile
3.4 3.2 Positive Programming Codes 3.0 Negative Programming Codes
TA = 150C, Magnetically Back-Biased VOUT(Q) = VOUT(Q)PRE, Sens = 5 mV/G
VOUT(Q) (V)
2.8 2.6 2.4 2.2 2.0 0 5 10 15 20 25 30
Sensitivity TC Code
Code 0 1 - 11 12 - 15 16 - 27 28 - 31 Application Initial code Positive TC codes, use to increase TC value [Unused, same effect as 4 - 7, respectively] Negative TC codes, use to decrease TC value [Unused, same effect as 20 - 23, respectively]
A1373-DS
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors
Sensitivity Temperature Coefficient Range, TC
0.25
0.20 Typical maximum attainable positive TC programming range
TCPRE(max)
A
0.15
Extended Range Not Guaranteed
0.10
TC(typ), for positive programming
TC (% / C)
0.05 Guaranteed Programmable Range 0 TC Range Before Programming
TC(typ), for negative programming TCPRE(min)
Extended Range Not Guaranteed
-0.05 Typical maximum attainable negative TC programming range
-0.10
-0.15
A
-0.20
Units with a TC in the range TC(min) < TC < TCPRE(max) before programming may not be programmable to the maximum attainable negative TC programming value
-0.25
A1373-DS
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors
Average Supply Current (Icc) vs Temperature Vcc = 5V
10.0
Average Supply Current (mA)
9.5 9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 -50
-25
0
25
50
75
100
125
150
Temperature (C)
Average Ratiometry, Voq
101.0 101.0
Average Ratiometry, Sens
100.8 100.6 100.4 100.2 100.0 99.8 99.6 99.4 99.2 99.0
Average Ratiometry (Voq) (%)
100.8 100.6 100.4 100.2 100.0 99.8 99.6 99.4 99.2 99.0 -50 -25 0 25 50 75 100 125 150 4.5 to 5.0 V 5.5 to 5.0 V
Average Ratiometry (Sens) (%)
4.5 to 5.0 V 5.5 to 5.0 V
-50
-25
0
25
50
75
100
125
150
Temperature (C)
Temperature (C)
Average Symmetry vs Temperature
101.0 100.8 100.6
Average Symmetry (%)
Average Linearity vs Temperature
101.0 100.8
Average Linearity (%)
100.6 100.4 100.2 100.0 99.8 99.6 99.4 99.2 99.0
100.4 100.2 100.0 99.8 99.6 99.4 99.2 99.0
-50 -25 0 25 50 75 100 125 150
Linearity + Linearity -
-50
-25
0
25
50
75
100
125
150
Temperature (C)
Temperature (C)
A1373-DS
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors
Average Delta Sensitivity (percent change relative to 25C)
8
25
Average Delta Sensitivity over TC Codes (percent change relative to 25C) Initial Coarse Range
Average Delta Sensitivity (%)
Sensitivity Low Sensitivity Mid Sensitivity High 4 2 0 -2 -4 -6
Initial Delta Sensitivity (%)
6
20 Sensitivity Low - TC Code 0 15 10 5 0 -5 -10 Sensitivity Low - TC Code 11 Sensitivity Low - TC Code 27
-50
-25
0
25
50 75 Temperature (C)
100
125
150
-15
-50
-25
0
25
50 75 Temperature (C)
100
125
150
Average Delta Sensitivity (percent per degree Celsius change relative to 25C)
0.08
Average Delta Sensitivity (percent per degree Celsius change relative to 25C) Initial Coarse Low
0.20 Sensitivity Low - TC Code 0 Sensitivity Low - TC Code 11 Sensitivity Low - TC Code 27
Average Delta Sensitvity (%/C)
0.06 0.04 0.02 0 -0.02 -0.04 -0.06 -0.08
Average Delta Sensitvity (%/C)
100 125 150
Sensitivity Low Sensitivity Mid Sensitivity High
0.15 0.10 0.05 0 -0.05 -0.10 -0.15
-50
-25
0
25
50 75 Temperature (C)
-0.20 -50
-25
0
25
50 75 Temperature (C)
100
125
150
Positive TC Contribution to Delta Sensitivity 15 10
TC Contribution to Delta Sensitivity (%)
Negative TC Contribution to Delta Sensitivity
10
TC Contribution to Delta Sensitivity (%)
TC Code 1 TC Code 2 TC Code 4 TC Code 8 TC Code 11
5 0 -5 -10 -15 -20
TC Code 16 TC Code 17 TC Code 18 TC Code 20 TC Code 24 TC Code 27
5 0 -5 -10
-50
-25
0
25
50
75
100
125
150
Temperature (C)
-50
-25
0
25 50 75 Temperature (C)
100
125
150
A1373-DS
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors
Average Quiescent Output Voltage
3.5 3.0 Average Vout(q) (V) 2.5 2.0 1.5 1.0 0.5 0 -50
Vout(q)Low - Initial Vout(q)Mid - Initial Vout(q)High - Initial
Average Delta Quiescent Output Voltage Relative to 25C, Initial Sensitivity
6
Average Delta Vout(q) (mV)
4 2 0 -2 -4 -6 -8 -10 Vout(q)Low Vout(q)Mid Vout(q)High -50 -25 0 25 50 75 100 125 150
-25
0
25
50 75 Temperature (C)
100
125
150
Temperature (C)
Average Quiescent Output Voltage Max Code (511)
Average Vout(q) (max Code - 511) (V) 6 5 Average Vout(q) (V) 4 3 2 1 0 -50
Vout(q)Low - Max Code Vout(q)Mid - Max Code Vout(q)High - Max Code
Average Initial Quiescent Output Voltage vs Supply Voltage TA = 25C
4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 150
Vout(q)Low - Initial Vout(q)Mid - Initial Vout(q)High - Initial
-25
0
25
50
75
100
125
4
4.5
Temperature (C)
5 Supply Voltage (V)
5.5
6
Average Quiescent Output Voltage over Sensitivity
1.85
1.83
Average Vout(q) (V)
Vout(q)Mid - SensLow Vout(q)Mid - SensMid Vout(q)Mid - SensHigh
1.81
1.79
1.77
1.75 -50 -25 0 25 50 75 100 125 150
Temperature (C)
A1373-DS
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors
Average Saturation Voltage
5 4
VOUT(sat) (V) Average Clamp Voltage (V) 5 4
Average Clamp Values
3 2 1 0
-50 -25 0 25 50 75 100 125 150 VOUT(sat)+ VOUT(sat)-
10% High Clamp 3 2 1 0 -50 -25 0 25 50 75 100 125 150 10% Low Clamp 20% High Clamp 20% Low Clamp
Temperature (C)
Temperature (C)
A1373-DS
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors
Chopper Stabilization Technique Chopper stabilization is a unique approach used to minimize Hall offset on the chip. The patented Allegro technique, namely Dynamic Quadrature Offset Cancellation, removes key sources of the output drift induced by thermal and mechanical stresses. This offset reduction technique is based on a signal modulationdemodulation process. The undesired offset signal is separated from the magnetic field-induced signal in the frequency domain, through modulation. The subsequent demodulation acts as a modulation process for the offset, causing the magnetic field-induced signal to recover its original spectrum at baseband, while the dc offset becomes a high-frequency signal. The magnetic-sourced signal then can
pass through a low-pass filter, while the modulated dc offset is suppressed. The chopper stabilization technique uses a 200 kHz high frequency clock. For demodulation process, a sample and hold technique is used, where the sampling is performed at twice the chopper frequency (400 kHz). This high-frequency operation allows a greater sampling rate, which results in higher accuracy and faster signal-processing capability. This approach desensitizes the chip to the effects of thermal and mechanical stresses, and produces devices that have extremely stable quiescent Hall output voltages and precise recoverability after temperature cycling. This technique is made possible through the use of a BiCMOS process, which allows the use of low-offset, low-noise amplifiers in combination with high-density logic integration and sample-and-hold circuits.
Regulator
Clock/Logic Hall Element Amp Low-Pass Filter
Concept of Chopper Stabilization Technique
Sample and Hold
A1373-DS
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors Definitions of Terms
Linear: A type of Hall-Effect sensor that produces an analog output voltage proportional to the strength of a sensed magnetic field. Ratiometric: A linear Hall-Effect sensor that, when not subjected to a significant magnetic field, has an output that is a ratio of its supply voltage. A ratiometric performance of 100% indicates the output follows the supply with no percentage error. Gauss: Standard unit of measuring magnetic flux density. 1 gauss is equal to 1 Maxwell per square centimeter or 10-4 tesla. (For reference, the earth's magnetic field is approximately 0.5 gauss.) Blowing: Applying a pulse of sufficient voltage and duration to permanently set a bit, by blowing a fuse internal to the device. Once a bit (fuse) has been blown, it cannot be reset. The terms trimming and programming can be used interchangeably with blowing in this context. Programming modes: Testing the results is the only valid method to guarantee successful programming, and multiple modes are provided to
support this. The programming modes are described in the section Mode Selection State.
Code: The number used to identify the register and the bitfield to be programmed, expressed as the decimal equivalent of the binary value. The LSB of a register is denoted as bit 0.
Typical Application Drawing
VREG 1 VCC A1373 A1374 GND 2 VOUT 3 RLOAD 4.7 k Sensor Output
CBYPASS 0.1 F
CLOAD 1 nF
A1373-DS
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors
Characteristic Definitions
Quiescent Output Voltage. In the quiescent state (no significant magnetic field: B = 0), the output, VOUTQ, equals a ratio of the supply voltage, VCC, throughout the entire operating ranges of VCC and ambient temperature, TA. Due to internal component tolerances and thermal considerations, however, there is a tolerance on the quiescent output voltage, VOUTQ, which is a function of both VCC and TA. For purposes of specification, the quiescent output voltage as a function of temperature, VOUTQ(TA), is defined as:
VOUTQ() = VOUTQ() - VOUTQ(25C) Sens(25C)
Ratiometric. The A1373 and A1374 feature ratiometric output. This means that the quiescent voltage output, VOUTQ, magnetic sensitivity, Sens, and clamp voltage, VOUTCLP , are proportional to the supply voltage, VCC. The ratiometric change in the quiescent output voltage, RATVOUT(Q) (%), is defined as:
RATVOUT(Q) = VOUTQ(VCC) VCC VOUTQ(5V) 5V x 100%
(4)
and the ratiometric change in sensitivity is defined as: (1)
RATSens = Sens(VCC) VCC Sens(5V) 5V x 100%
(5)
where Sens is in mV/G, and the result is the device equivalent accuracy, in gauss (G), applicable over the entire operating temperature range. Sensitivity. The presence of a south-polarity (+B) magnetic field, perpendicular to the branded face of the device package, increases the output voltage, VOUT, in proportion to the magnetic field applied, from VOUTQ toward the VCC rail. Conversely, the application of a north polarity (-B) magnetic field, in the same orientation, proportionally decreases the output voltage from its quiescent value. This proportionality is specified as the magnetic sensitivity of the device and is defined as:
Sens = VOUT(-B) - VOUT(+B) 2B
and the ratiometric change in clamp voltage is defined as:
RATVCLP = VCLP(VCC) VCC VCLP(5V) 5V x 100%
(6)
Linearity and Symmetry. The on-chip output stage is designed to provide linear output at a supply voltage of 5 V. Although the application of very high magnetic fields does not damage these devices, it does force their output into a nonlinear region. Linearity in percent is measured and defined as:
Lin+ = VOUT(+B) - VOUTQ 2 (VOUT(+B1/2) - VVOUTQ ) VOUT(-B) - VOUTQ 2(VOUT(-B1/2) - VOUTQ) VOUT(+B) - VOUTQ VOUTQ - VOUT(-B) x 100%
(7)
(2)
Lin- =
x 100%
(8)
The stability of the device magnetic sensitivity as a function of ambient temperature, Sens (TA) (%) is defined as:
Sens() = Sens() - Sens(25C) Sens(25C) x 100%
and output symmetry as:
Sym = x 100%
(3)
(9)
A1373-DS
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors Pulse Generation
Several parameters can be field-programmed. To do so, a coded series of voltage pulses through the VOUT pin is used to set bitfields in onboard registers. The effect on the device output can be monitored, and the registers can be cleared and set repeatedly until the required output results are achieved. To make the setting permanent, bitfield-level solid state fuses are blown, and finally, a device-level fuse is blown, blocking any further coding. Although any programmable variable power supply can be used to generate the pulsed waveforms, Allegro highly recommends using the Allegro Sensor Evaluation Kit, available on the Allegro Web site On-line Store. The manual for that kit is available for download free of charge, and provides additional information on programming these devices. There are four relative nominal voltage levels that must be taken into account when programming. For purposes of explanation in this document, the signal levels are referred to simply as high programming voltage, VPH, midrange, VPM, and low, VPL. The fourth voltage level, VR, is a very low level, near zero volts, used to reset the bitfields that have not yet been isolated by blown fuses. The high level, VPH, pulse is maintained either for short duration (tPH = 1 to <<35 s), acting as a strobe to signal the transition between states, or for long duration (tPH 35 s) and used for fuse-blowing. The device generates an internal pulse beginning at the leading (rising) edge of a VPH pulse. The duration of the internal pulse is the duration of the external VPH pulse, tPH, plus 15 s. The added time is a buffer to compensate for voltage drop when the high current is sourced, ensuring that there is sufficient power to blow the fuse completely. Before sending another pulse, an additional guard band of 5 s is recommended to allow the signal to decay, for a total of at least 20 s after the end of any VPH pulse. tPH is measured from the time when the external signal voltage rises above 23.6 V to the time when it falls below 19.4 V. The nominal level for VPH is 28 V.
Change State 1 < tPH < 35 s VPH
Blow Fuse tPH > 35 s
External Pulses on VOUT Pin
VPM
VPL Guard Band (20 s)
VR
Guard Band (6 s)
Blowing fuse tmin 50 s
Logic 1
Internal Pulses
Logic 0
Bit setting pulses = 5 s State Change or Blow pulse = tPH +15 s
Note: Spurious bit-setting pulses are generated on first V > VPL after VR, and at last VPL.
Programming Pulse Waveforms
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors
The midrange voltage level, VPM, is a neutral level, used to separate both VPH and VPL pulses from each other. The nominal level for VPM is 15 V. The low level, VPL, pulse is used to indicate bitfield addresses that are to be set. The device generates an internal pulse beginning at the leading (falling) edge of a VPL pulse. The duration of the internal pulse is 5 s. Before allowing the voltage to rise again, an additional guard band of 1 s is recommended to ensure that the pulse completes, for a total of at least 6 s after the start of any VPL pulse. The duration of the VPL pulse, tPL , is measured from the time when the external signal voltage falls into the range 0 to 7.5 V to the time when it rises above 10 V. If the voltage rises above 10 V before the 5 s period expires, then
the VPL pulse will immediately end, with undefined results. The nominal level for VPH is 5 V. VPL must always be maintained high enough above VR (nominally 0 V) to maintain the settings provisionally latched into registers. Note that, when the external voltage rises from VR through the VPL range, a spurious internal pulse is generated, making Code 0 not available in Mode Selection state. A spurious internal pulse also is generated when the external voltage falls through the VPL range at the end of a code sequence. For that reason, it is mandatory to ensure that the voltage is dropped fully to VR, before every Blow Fuse mode operation, to ensure that the spurious pulse does not affect the next code sequence.
A1373-DS
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors Programming State Machine
POWER UP
INITIAL STATE VPH
VPH MODE SELECT VPL TRY 1 VPH VPL BLOW 2 VPH VPL LOCK 3 VPH
VPL
REGISTER SELECT
VPL QVO VPL Coarse 0 VPH QVO Fine 1 VPH VPL SENS. VPL Coarse 2 VPH SENS. Fine 3 VPH VPL SENS. TC 4 VPH VPL CLAMP VPL 5 VPH POLAR 6 VPH
BITFIELD SELECT [Optional: Measure] 0 VPL 1 [Optional: Measure] VPL 2
[Write Mode]
BITFIELD SELECT
[Optional: Measure] VPL 2^N -1
VPL VPL
VPH
VPH
VPH
VPH
VPH
No
BLOWING MODE?
Yes
FUSE BLOWING
User generated transition Internally generated transition
A1373-DS
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors Programming Protocol and State Machine Description
INITIAL STATE
After system power-up, the programming logic is reset to a known state. This is referred to as the Initial state. All the registers that have intact fuses are set to logic 0. While in the Initial state, any VPL pulses on the VOUT pin are ignored. To enter the Mode Selection state, send one VPH pulse on the VOUT pin.
device (2 bits) * Sens. Fine. Register for setting the value within the range set in the Sens. Coarse register (8 bits) * [Sensitivity] TC Register. Register for setting the temperature coefficient for the device (5 bits). * Clamp [VOUTCLP] Bit. Register for setting the clamping voltage of the output (2 bits) * Polarity Bit. Register setting the polarity of the output (1 bit)
MODE SELECTION STATE
This state allows the selection of the programming mode:
* Try Value Mode. In this mode, the user provisionally downloads settings to the device registers, without blowing the bits. The user can increment through the codes of each parameter, and evaluate the results of various code settings. * Blow Fuse Mode. In this mode, after downloading the settings, the user can blow the fuses in specific registers. * Lock Device Mode. This mode is similar to Blow Fuse mode, except that the fuse that is blown permanently prevents any further programming of any bits in the device.
To select a register, increment through the register bitfields by sending VPL pulses on the VOUT pin. Note that the programming of registers should follow the order shown in item 7 in the section Programming Guidelines, not the bitfield selection order shown here. The bitfield selection order is:
0 pulses - QVO Coarse register 1 pulse - QVO Fine register 2 pulses - Sens. Coarse register 3 pulses - Sense Fine register 4 pulses - TC Register register 5 pulses - Clamp Bit register 6 pulses - Polarity Bit register
This register wraps by default. To enter the Register Selection state, send one VPH pulse on the VOUT pin.
To select a mode, increment through the register bitfields by sending VPL pulses on the VOUT pin, as follows:
0 pulses - No effect 1 pulse - Try Value mode 2 pulses - Blow Fuse mode 3 pulses - Lock Device mode
BITFIELD SELECTION STATE (Write Mode)
This state allows the selection of the individual bitfields to be programmed, in the register selected in the Register Selection state. In Try Value mode, the total value of the bitfields selected increments by 1 with each VPL pulse on the VOUT pin. The parameter being programmed changes with each additional pulse, so measurements can be taken after each pulse to determine if the desired result has been acquired. In Blow Fuses mode, each bitfield to be blown must be selected individually. For bit codes and wrapping for these registers, see the section Programming Logic. To leave this state, send one VPH pulse on the VOUT pin. If the current mode is Try Value, the bitfields remain set and the device reverts to the Mode Selection state. If the current mode is Blow Fuse, the selected bitfield fuse is blown, and the device reverts to the Mode Selection state.
This register wraps by default. This means that sending additional VPL pulses traverses the register again. Any VPH pulse sent before a VPL pulse has no effect. To enter the Register Selection state, after sending a valid quantity of VPL pulses, send one VPH pulse on the VOUT pin.
REGISTER SELECTION STATE
This state allows the selection of the register containing the bitfields to be programmed. Selecting the register corresponds to selecting the parameter to be set. For bit codes, see the section Programming Logic.
* QVO [VOUT(Q)] Coarse. Register for setting the range of the operating dc point (2 bits) * QVO Fine. Register for setting the value within the range set in the QVO Coarse register (9 bits) * Sens. [Sensivity] Coarse. Register for setting the overall gain of the
A1373-DS
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors Programming Logic
Binary Bitfield Address QVO Coarse register 00 01 10 11 QVO Fine register 000000000 111111111 Sens. Coarse register 00 01 10 11 Sens. Fine register 00000000 11111111 00000 00001 through 01011 01100 through 01111 10000 through 11011 11100 through 11111 Clamp Bit register 00 01 10 00 Polarity Bit register 0 1
Decimal Equivalent Code 0 1 2 3 0 511 0 1 2 3 0 255 0 1 through 11 12 through 15 16 through 27 28 through 31 0 1 2 3 0 1 VOUT(Q) mid range VOUT(Q) low range VOUT(Q) high range Register wraps to 00
Description
Initial value in selected QVO Coarse range Maximum value in selected QVO Coarse range Sens low range Sens mid range Sens high range Register wraps to 00 Initial value in selected Sens. Coarse range Maximum value in selected Sens. Coarse range initial TC Positive TC programming range Unused: equal to codes 4 to 7, respectively Negative TC prgramming range; Value for 16 equals 1 step less than the value for the Initial TC Value (00000) Unused: equal to codes 20 to 23, respectively Rail-to-rail output swing 0.5 V and VCC- 0.5V rails 1 V and VCC - 1 V rails Register wraps to 00 Positive (VOUT increases when a positive (south) magnetic field is applied to the device ) Negative (VOUT increases when a negative (north) magnetic field is applied to the device )
TC Register register (See also chart Sensitivity Temperature Coefficient Code Profile in Typical Characteristics section)
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Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors Programming Guidelines
* A bypass capacitor rated at 0.1F must be mounted between the VOUT pin and the GND pin during programming. The power supply used for programming should be capable of delivering 28 V and 300 mA. * Before beginning any Blow Fuse mode or Lock Device mode code sequence, the device MUST be reset by cycling VCC power-off and power-on again. Cycling power resets the device by setting all bitfields that have intact fuses to 0. Bitfields with blown fuses are unaffected. In Try Value mode, to retain register settings from previous code sequences, do not cycle power between sequences. When a register is selected in Register Selection mode, when the VPH pulse is sent to enter the Bitfield Selection mode, the bitfields with intact fuses in that register are reset to 0. * In Try Value mode, all bits in the register can be set in one code sequence. For example, setting the binary value 0110 and sending a VPH pulse sets code 6. However, because of the power requirement, blowing fuses must be performed one bitfield at a time. In order to program (blow fuses) for binary 0110, the bitfields MUST be programmed (blown) in two different code sequences:one setting the 0100 bit, and the other setting the 0010 bit (in either order). Power must be cycled before each of the two sequences. * Although a bitfield cannot be reset once its fuse is blown, additional bitfields can be blown at any time, until the device is locked by setting the Lock bit. For example, if bit 1 (0010) has been blown, it is possible to blow bit 0 (0001). Because bit 1 was already blown, the end result will be 0011 (code 3). * Before powering down the device after programming, observe the recommended delay, to ensure that the last VPH pulse has decayed before voltage drops to the VPL voltage. This will avoid the generation of overlapping VPL and VPH pulses. At the end of a Lock Device mode code sequence, the delay is not necessary. * Programming order is important in both Try Value mode and in Blow Fuse mode. There will be a slight parametric shift in sensitivity after programming the temperature coefficient, and a slight quiescent voltage shift with polarity. Subsequent changes to sensitivity can cause a shift in the quiescent output voltage. The following order is recommended:
a. b. c. d. e. g. Polarity TC Register Sens Coarse QVO Coarse Sens Fine QVO Fine
The Clamp Bit register can be programmed at any point in the order, as no parametric shift is observed due to clamps. * The actual distribution of parametric programming ranges are wider than the specified programming ranges, in order to take in to account manufacturing spread. The maximum possible attainable range can be used with the understanding that other specified parameters might be out of datasheet specification in the extended range. (For an example, see the chart Sensitivity Temperature Coefficient Range, in the Typical Characteristics section.)
A1373-DS
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors Programming Example
This example demonstrates the programming of the devices by setting the register for Sensitivity Temperature Coefficient to 00110. 1. Power-on the system. This will reset the unprogrammed bits in all registers to 0. The device enters the Initial state. 2. Send one VPH pulse to enter the Mode Selection state. 3. Send one VPL pulse to select Try Value mode. 4. Send one VPH pulse to enter the Register Selection state. 5. Send four VPL pulses to select the TC register. 6. Send one VPH pulse to enter Bitfield Selection state (Write mode). The TC register is reset to 00000 (assuming all of those bitfields have intact fuses). 7. Send five VPL pulses to set bitfields 0 and 2 (00101). Now we can measure the device output to see if this is the desired value. We may find that the value we programmed is not correct. So we will proceed to change it, as follows: 8. Send one VPL pulse to increase the code to 6 (setting bitfields 1 and 2: 00110). We measure the device and find that this is the correct TC we require. We are finished with trying values, and now want to set the value permanently. In the following steps, remember that blowing fuses is done one bit at a time. 9. Send one VPH pulse to exit Bitfield Selection mode. (The device returns to the Mode Selection state.) 10. RESET the device by powering it off and on. 11. Send one VPH pulse to enter the Mode Selection state. 12. Send two VPL pulses to select Blow Fuse mode.
13. Send one VPH pulse to enter the Register Selection state. 14. Send four VPL pulses to select the TC register. 15. Send one VPH pulse to enter Bitfield Selection state (Write Mode). The TC register is reset to 00000. 16. Send four VPL pulses to set bit 2 (00100, decimal 4). 17. Send one VPH pulse to exit Bitfield Selection state. The bitfield fuse is blown, and the device returns to the Mode Selection state. One of the two bitfields is programmed. Now we program the other bitfield. 18. Repeat steps 10 to 15 to select the TC register again. This time, however, the register resets to 00100, because bit 2 has been permanently set. 19. Send two VPL pulses to set bit 1 (00010, decimal 2). 20. Send one VPH pulse to exit Bitfield Selection state. The bitfield fuse is blown, and the device returns to the Mode Selection state. After repeating the above steps to program all parameters, we can lock the device: 21. RESET the device by powering it off and on. 22. Send one VPH pulse to enter the Mode Selection state. 23. Send three VPL pulses to select Lock Device mode. 24. Send one VPH pulse to enter the Bitfield Selection state. (We do not need to select a register for locking the device). 25. Send one VPL pulse to set the Lock bit to 1. 26. Send one VPH pulse to exit Bitfield Selection state. The bitfield fuse is blown, and the device returns to the Mode Selection state. 27. Programming the device is complete. Optionally, test the results, or power-off the device.
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Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors
Package KB, 3-Pin SIP
.208 5.28 .203 5.16 45 BSC .0165 .042 B NOM .063 1.60 .059 1.50
.138 3.51 .133 3.38
45 BSC .085 2.16 MAX A .0189 0.48 .0142 0.36 C .033 0.84 REF
.600 .560
15.25 14.24
.020 0.51 REF .030 0.75 REF 1 .023 .018 0.58 0.46 2 3
.0173 0.44 .0138 0.35
.075 1.91 BSC
Dimensions in inches Metric dimensions (mm) in brackets, for reference only A Dambar removal protrusion
B Hall element Active Area Depth
C Leads 1 and 3 only
A1373-DS
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
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A1373 and A1374
High Precision, Output Pin Programmable, Linear Hall Effect Sensors
The products described herein are manufactured under one or more of the following U.S. patents: 5,045,920; 5,264,783; 5,442,283; 5,389,889; 5,581,179; 5,517,112; 5,619,137; 5,621,319; 5,650,719; 5,686,894; 5,694,038; 5,729,130; 5,917,320; and other patents pending. 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 performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the information being relied upon is current. Allegro products are not authorized for use as critical components in life-support devices or systems without express written approval. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringement of patents or other rights of third parties which may result from its use. Copyright (c) 2005, Allegro MicroSystems, Inc.
A1373-DS
Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com
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