A1374EKB - Allegro MicroSystems, Inc.

A1373 and A1374

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

AB SO LUTE MAX I MUM RAT INGS

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.................. –40ºC to 85ºC

Ambient, TA, Range L................ –40ºC to 150ºC

Maximum Junction, TJ(max)........................165ºC

Storage Temperature, TS.................. –65ºC to 170ºC

High Precision, Output Pin Programmable

Linear Hall Effect Sensors

Features and Benefits

Package KB, 3-pin SIP

123

1. VCC

2. GND

3. VOUT (Programming)

The A1373 and A1374 high precision linear Hall effect sensors are sensitive, tem-

perature stable, linear devices with externally programmable features. This device

family incorporates a chopper-stabilized amplifier, voltage regulator, program-

ming 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-potentiom-

eter 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 coef-

ficient, 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 simpli-

fied.

These devices are available in the KB package, a 3-pin SIP (single inline pack-

age). The lead (Pb) free version has a 100% matte tin plated leadframe.

1When blowing fuses during device programming, a

voltage of 28 V may be applied to VOUT.

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

Wide lead-spacing with KB package

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

Product Selection Guide

Functional Block Diagram

Amp Out

VCC

Pin 3

VOUT

GND

Pin 2

Pin 1

Filter

Dynamic Offset

Cancellation

Gain

Temperature

Coefficient

Offset

Voltage

Regulator

Trim Control

To all subcircuits

Hall drive circuit

*Contact Allegro for additional packing options

Part Number

Pb-

free Packing*

Ambient, TA

(ºC)

A1373EKB – Bulk, 500 pcs./bag

A1373EKB–T Yes –40 to 85

A1373EKBTI –

14.24-in. reel, 2000 pcs/reel

A1373EKBTI–T Yes

A1373LKB – Bulk, 500 pcs./bag

A1373LKB–T Yes –40 to 150

A1373LKBTI – 14.24-in. reel, 2000 pcs/reel

A1373LKBTI–T Yes

A1374EKB – Bulk, 500 pcs./bag

A1374EKB–T Yes –40 to 85

A1374EKBTI – 14.24-in. reel, 2000 pcs/reel

A1374EKBTI–T Yes

A1374LKB – Bulk, 500 pcs./bag

A1374LKB–T Yes –40 to 150

A1374LKBTI – 14.24-in. reel, 2000 pcs/reel

A1374LKBTI–T Yes

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

Characteristic Symbol Test Conditions Min. Typ. Max Units

ELECTRICAL CHARACTERISTICS over operating temperature range, VCC= 5.0 V, unless otherwise noted

Supply Voltage VCC

Operation within specification,

Tj < 165°C 4.5 5.0 5.5 V

Supply Current ICC – 8.2 10 mA

Reverse-Supply Current IRCC VCC = –16 V, TA = 25°C – – 16 mA

Power-On Time1tPO CLOAD = 10 nF, 90% full scale VOUT – – 300 µs

Chopping Frequency fC– 200 – kHz

Internal Bandwidth BW A1373 Small signal -3 dB – 2.5 – kHz

A1374 – 20 – kHz

OUTPUT CHARACTERISTICS over operating temperature range, VCC= 5.0 V, unless otherwise noted

Noise2,3 VN

A1373 peak-to-peak, CLOAD > 1 nF,

2.5 mV/G

– 6 16 mV

A1374 – 14 26 mV

Output Capacitance Load CLOAD VOUT pin to GND pin – – 10 nF

Output Resistive Load RLOAD 4700 – – Ω

Phase Shift ∆Φ

A1373 Magnetic signal freq. = 100 Hz – 3 – (°)

A1374 Magnetic signal freq. = 1000 Hz – 3 – (°)

Output Voltage

VOUT(Sat)HIGH

IOUTSINK = 1.2 mA,

B(kG) > (VCC–VOUT(Q)) / Sens (mV/G) 4.65 4.7 – V

VOUT(Sat)LOW

IOUTSOURCE = 1.2 mA,

B(kG) < VOUT(Q) / Sens (mV/G) – 0.2 0.25 V

Output Resistance ROUT – 1.5 – Ω

MAGNETIC CHARACTERISTICS

Magnetic Slew Rate SLR V/ms / Sens – 20 – G/µs

PRE-PROGRAMMING TARGET (Prior to coarse and fine trim) over operating temperature range, VCC= 5.0 V, unless

otherwise noted

Pre-Programming Quiescent

Output Voltage VOUT(Q)PRE B = 0 G, TA = 25°C 1.62 1.80 1.98 V

Pre-Programming Sensitivity SensPRE TA = 25°C 1.05 1.31 1.75 mV/G

Pre-Programming Sensitivity

Temperature Coefficient TCPRE TA relative to 25°C –0.016 0.05 0.104 %/°C

INITIAL COARSE PROGRAMMING over operating temperature range, VCC= 5.0 V, unless otherwise noted

Initial Coarse Quiescent Output

Voltage

VOUT(Q)INITLOW TA = 25°C – 0.55 – V

VOUT(Q)INITMID Reference VOUT(Q)PRE ––- –V

VOUT(Q)INITHIGH TA = 25°C – 3.25 – V

Initial Coarse Sensitivity

SensINITLOW Reference SensPRE – – – mV/G

SensINITMID TA = 25°C – 2.8 – mV/G

SensINITHIGH TA = 25°C – 5.5 – mV/G

CHARACTERISTIC PARAMETERS

Continued on the next page...

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

QUIESCENT OUTPUT VOLTAGE PROGRAMMING over operating temperature range, VCC= 5.0 V, unless otherwise noted

Quiescent Output Voltage Range

VOUT(Q)LOW

B = 0 G, TA = 25°C

0.7 – 1.9 V

VOUT(Q)MID 2.0 – 3.2 V

VOUT(Q)HIGH 3.5 – 4.5 V

Average Quiescent Output Voltage

Step Size4,5,6 StepVOUT(Q) TA = 25°C 3.0 3.275 3.5 mV

Quiescent Output Voltage

Programming Resolution ErrPROGVOUT(Q)

Fine programming value selection

accuracy –±0.5 ×

StepVOUT(Q)

–mV

Quiescent Output Voltage Drift

Over Operating Temperature

Range

∆VOUT(Q)

VOUT(Q) = VOUT(Q)LOW – – ±40 mV

VOUT(Q) = VOUT(Q)MID – – ±40 mV

VOUT(Q) = VOUT(Q)HIGH – – ±55 mV

Quiescent Output Voltage

Programming Bits –Coarse (Range selection) – 2 – Bit

Fine (Value selection) – 9 – Bit

10% Output Clamp Option7

VOUTCLP10HIGH

A1373 High-side output clamp 4.350 – 4.565 V

A1374 4.300 – 4.650 V

VOUTCLP10LOW

A1373 Low-side output clamp 0.4 – 0.6 V

A1374 0.3 – 0.6 V

20% Output Clamp Option7

VOUTCLP20HIGH

A1373 High-side output clamp 3.925 – 4.125 V

A1374 3.900 – 4.200 V

VOUTCLP20LOW

A1373 Low-side output clamp 0.9 – 1.1 V

A1374 0.8 – 1.1 V

Delay to Clamp tCLP

A1373 – – 2 µs

A1374 – – 100 µs

SENSITIVITY PROGRAMMING over operating temperature range, VCC= 5.0 V, unless otherwise noted

Sensitivity Range8

SensLOW

TA = 25°C

1.75 – 3.0 mV/G

SensMID 3.5 – 6.0 mV/G

SensHIGH 7.0 – 11.75 mV/G

Average Sensitivity Step Size4,5,6

StepSENSLOW

TA = 25°C

6 9.5 14 µV/G

StepSENSMID 12 18.7 28 µV/G

StepSENSHIGH 22 37.0 56 µV/G

Sensitivity Programming

Resolution ErrPROGSENS

Fine programming value selection

accuracy –±0.5 ×

StepSENS

– µV/G

Sensitivity Programming Bits –Coarse (Range selection) – 2 – Bit

Fine (Value selection) – 8 – Bit

POLARITY PROGRAMMING

Polarity Programming Bit – Negative Sensitivity – 1 – Bit

CHARACTERISTIC PARAMETERS (continued)

Continued on the next page...

Characteristic Symbol Test Conditions Min. Typ. Max Units

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

CHARACTERISTIC PARAMETERS (continued)

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

–0.07 –%/°C

Sensitivity T/C codes 16 to 27,

minimum (absolute) negative

temperature coefficient attainable

––0.016 – %/°C

Average Sensitivity

Temperature Coefficient Step

Size4,5,6

StepTC TA = 150°C–0.01 –%/°C

Sensitivity Temperature

Coefficient Programming Bits ––

5– Bit

ONE-TIME PROGRAMMING

Device Programming Lock Bit – – 1 – Bit

RATIOMETRY over operating temperature range, VCC= 5.0 V, unless otherwise noted

Quiescent Voltage Error RatVOUT(Q) VCC at VOPERATING –±0.25 –%

Sensitivity Error RatSENS VCC at VOPERATING –±1.0 –%

Clamp Error RatVOUTCLP VCC at VOPERATING –±1.5 –%

LINEARITY over operating temperature range, VCC= 5.0 V, unless otherwise noted

Positive Linearity Error Lin+ VCC at VOPERATING –±0.5 –%

Negative Linearity Error Lin– VCC at VOPERATING –±0.5 –%

SYMMETRY over operating temperature range, VCC= 5.0 V, unless otherwise noted

Symmetry Error Sym VCC at VOPERATING – VCC –±0.35 – %

ADDITIONAL CHARACTERISTICS

Sensitivity Drift9∆Sens – – ±2 %

FAULT CONDITIONS over operating temperature range, VCC= 5.0 V, unless otherwise noted

Shorted Output Wire IOUTSHT

VOUT pin to VCC pin – – 18 mA

VOUT pin to GND pin – – 4 mA

1 tPO does not include tCLP , specified in the Quiescent Programming sectio n of this table.

2 Peak to peak value exceeded: 0.3% (6σ).

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 2× 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 VOUTCLP 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 25°C

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.

Characteristic Symbol Test Conditions Min. Typ. Max Units

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

Typical Characteristics

2.0

2.2

2.4

2.6

2.8

3.0

3.2

3.4

0 5 10 15 20 25 30

Sensitivity TC Code

OUT(Q)

(V)

Temperature Coefficient Code Profile

= 150°C, Magnetically Back-Biased

OUT(Q)

= V

OUT(Q)PRE

, Sens = 5 mV/G

Code Application

0 Initial code

1 – 11 Positive TC codes, use to increase TC value

12 – 15 [Unused, same effect as 4 – 7, respectively]

16 – 27 Negative TC codes, use to decrease TC value

28 – 31 [Unused, same effect as 20 – 23, respectively]

Positive Programming Codes

Negative Programming Codes

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

Sensitivity Temperature Coefficient Range, TC

TC (% / °C)

0.25

–0.25

0.20

–0.20

0.15

–0.15

0.10

–0.10

0.05

–0.05

(typ)

, for positive programming

Typical maximum attainable

positive TC programming range

TCPRE(max)

(typ)

, for negative programming

TCPRE(min)

Typical maximum attainable

negative TC programming range

TC Range Before Programming

Units with a TC in the range TC

(min)

< TC < TC

PRE(max)

before programming may not be programmable

to the maximum attainable negative TC programming value

Extended Range Not Guaranteed

Guaranteed Programmable Range

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

Average Supply Current (Icc) vs Temperature

Vcc = 5V

Temperature (°C)

Average Supply Current (mA)

Temperature (°C)

Average Ratiometry (Voq) (%)

4.5 to 5.0 V

5.5 to 5.0 V

Average Linearity vs Temperature

-50 -25 0 25 50 75 100 125 150

Temperature (°C)

Average Linearity (%)

Linearity +

Linearit

Average Symmetry vs Temperature

-50 -25 0 25 50 75 100 125 150

Temperature (°C)

Average Symmetry (%)

-50-250255075100125150

-50 -25 0 25 50 75 100 125 150

Temperature (°C)

Average Ratiometry (Sens) (%)

4.5 to 5.0 V

5.5 to 5.0 V

-50-250255075100125150

Average Ratiometry, Voq

Average Ratiometry, Sens

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

9.5

10.0

99.0

99.2

99.4

99.6

99.8

100.0

100.2

100.4

100.6

100.8

101.0

99.0

99.2

99.4

99.6

99.8

100.0

100.2

100.4

100.6

100.8

101.0

99.0

99.2

99.4

99.6

99.8

100.0

100.2

100.4

100.6

100.8

101.0

99.0

99.2

99.4

99.6

99.8

100.0

100.2

100.4

100.6

100.8

101.0

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

Average Delta Sensitivity

(percent change relative to 25°C)

-6

-4

-2

-50 -25 0 25 50 75 100 125 150

Temperature (°C)

Average Delta Sensitivity (%)

Sensitivity Low

Sensitivity Mid

Sensitivity High

Average Delta Sensitivity over TC Codes

(percent change relative to 25°C)

Initial Coarse Range

-15

-10

-5

-50 -25 0 25 50 75 100 125 150

Temperature (°C)

Initial Delta Sensitivity (%)

Sensitivity Low - TC Code 0

Sensitivity Low - TC Code 11

Sensitivity Low - TC Code 27

Average Delta Sensitivity

(percent per degree Celsius change relative to 25°C)

-0.08

-0.06

-0.04

-0.02

0.02

0.04

0.06

0.08

-50 -25 0 25 50 75 100 125 150

Temperature (°C)

Average Delta Sensitvity (%/°C)

Sensitivity Low

Sensitivity Mid

Sensitivity High

Average Delta Sensitivity

(percent per degree Celsius change relative to 25°C)

Initial Coarse Low

-50 -25 0 25 50 75 100 125 150

Temperature (°C)

Average Delta Sensitvity (%/°C)

Sensitivity Low - TC Code 0

Sensitivity Low - TC Code 11

Sensitivity Low - TC Code 27

Positive TC Contribution to Delta Sensitivity

-50 -25 0 25 50 75 100 125 150

Temperature (°C)

TC Contribution to

Delta Sensitivity (%)

TC Code 1

TC Code 2

TC Code 4

TC Code 8

TC Code 11

Negative TC Contribution to Delta Sensitivity

-20

-15

-10

-5

-50 -25 0 25 50 75 100 125 150

Temperature (°C)

TC Contribution to Delta

Sensitivity (%)

TC Code 16

TC Code 17

TC Code 18

TC Code 20

TC Code 24

TC Code 27

-0.20

-0.15

-0.10

-0.05

0.05

0.10

0.15

0.20

-10

-5

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

-50 -25 0 25 50 75 100 125 150

Temperature (°C)

Average Vout(q) (V)

Vout(q)Low - Initial

Vout(q)Mid - Initial

Vout(q)High - Initial

Average Quiescent Output Voltage

Max Code (511)

-50 -25 0 25 50 75 100 125 150

Temperature (°C)

Average Vout(q) (max Code - 511) (V)

Vout(q)Low - Max Code

Vout(q)Mid - Max Code

Vout(q)High - Max Code

Relative to 25°C, Initial Sensitivity

-10

-8

-6

-4

-2

-50 -25 0 25 50 75 100 125 150

Temperature (°C)

Average Delta Vout(q) (mV)

Vout(q)Low

Vout(q)Mid

Vout(q)High

Average Quiescent Output Voltage over Sensitivity

1.75

1.77

1.79

1.81

1.83

1.85

-50 -25 0 25 50 75 100 125 150

Temperature (°C)

Average Vout(q) (V)

Vout(q)Mid - SensLow

Vout(q)Mid - SensMid

Vout(q)Mid - SensHigh

Average Initial Quiescent Output Voltage vs Supply Voltage

TA = 25°C

4 4.5 5 5.5 6

Supply Voltage (V)

Average Vout(q) (V)

Vout(q)Low - Initial

Vout(q)Mid - Initial

Vout(q)High - Initial

Average Quiescent Output Voltage

Average Delta Quiescent Output Voltage

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

-50 -25 0 25 50 75 100 125 150

VOUT(sat) (V)

VOUT(sat)+

VOUT(sat)–

-50 -25 0 25 50 75 100 125 150

Temperature (°C)

Average Clamp Voltage (V)

10% High Clamp

10% Low Clamp

20% High Clamp

20% Low Clam

Average Clamp Values

Temperature (°C)

Average Saturation Voltage

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

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 modulation-

demodulation 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 recoverabil-

ity 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-den-

sity logic integration and sample-and-hold circuits.

Amp

Regulator

Clock/Logic

Hall Element

Sample and

Hold

Low-Pass

Filter

Concept of Chopper Stabilization Technique

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

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.

Definitions of Terms

Typical Application Drawing

VCC

VREG

Sensor Output

GND

VOUT

CBYPASS

0.1 µF CLOAD

1nF

RLOAD

4.7 kΩ

A1373

A1374

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

Characteristic Definitions

Quiescent Output Voltage. In the quiescent state (no signifi-

cant 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 compo-

nent tolerances and thermal considerations, however, there is

a tolerance on the quiescent output voltage, ∆V

OUTQ, which is

a function of both ∆V

CC and ∆TA. For purposes of specifica-

tion, the quiescent output voltage as a function of temperature,

∆V

OUTQ(∆TA), is defined as:

where Sens is in mV/G, and the result is the device equivalent

accuracy, in gauss (G), applicable over the entire operating tem-

perature 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:

The stability of the device magnetic sensitivity as a function of

ambient temperature, ∆ Sens (∆TA) (%) is defined as:

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:

and the ratiometric change in sensitivity is defined as:

and the ratiometric change in clamp voltage is defined as:

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:

and output symmetry as:

∆VOUTQ(∆ΤΑ)Sens(25ºC)

VOUTQ(ΤΑ)VOUTQ(25ºC)

–

=(1)

VOUT(–B) VOUT(+B)

Sens

–

∆Sens(∆ΤΑ)

Sens(ΤΑ)Sens(25ºC)

Sens(25ºC)

–

=× 100%

(2)

(3)

OUTQ(V

)

OUTQ(5V)

RAT

VOUT(Q)

=× 100%

(4)

VCC 5V

=× 100%

RATSens

Sens(VCC)Sens(5V)

(5)

=× 100%

Lin+

2 (VOUT(+B½) –V

VOUTQ )

–

VOUT(+B) VOUTQ

(7)

=× 100%

Lin–

2(VOUT(–B½) –V

OUTQ)

–

VOUT(–B) VOUTQ

(8)

–

=× 100%

Sym

VOUT(+B)

VOUTQ –V

OUT(–B)

VOUTQ

(9)

RATVCLP VCC 5V

VCLP(VCC)VCLP(5V)

× 100%

(6)

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

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Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

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 repeat-

edly 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 µs), acting as a strobe to signal the transition

between states, or for long duration (∆tPH ≥ 35 µs) 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 µs. The added time is a buffer to compensate for volt-

age 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 µs is recommended

to allow the signal to decay, for a total of at least 20 µs 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.

1 < ∆tPH < 35 µs ∆tPH > 35 µs

External Pulses

on VOUT Pin

Internal Pulses

Logic 0

Logic 1

Change State

Bit setting pulses = 5 µs

State Change or Blow pulse = ∆tPH +15 µs

Note: Spurious bit-setting pulses are generated on first V > VPL after VR, and at last VPL.

Guard

Band

(20 µs) Guard Band (6 µs)

VPH

VPM

VPL

Blow Fuse

tmin ≥ 50 µs

Blowing fuse

Programming Pulse Waveforms

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

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Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

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 begin-

ning at the leading (falling) edge of a VPL pulse. The duration

of the internal pulse is 5 µs. Before allowing the voltage to

rise again, an additional guard band of 1 µs is recommended to

ensure that the pulse completes, for a total of at least 6 µs 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 µs 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 (nomi-

nally 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 Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

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Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

POWER UP

INITIAL STATE

MODE SELECT

BITFIELD SELECT BITFIELD SELECT

BLOWTRY LOCK

QVO

Fine

SENS.

Coarse

SENS.

Fine

QVO

Coarse CLAMP

TC POLAR

1 20 2^N -1

BLOWING

MODE?

VPH

VPL

12 3

01234 56

VPL

VPH

VPHVPH VPH

VPL

VPHVPH VPH VPH VPHVPHVPH

VPL VPL VPL

VPHVPHVPH

[Optional:

Measure]

[Optional:

Measure]

[Optional:

Measure]

[Write Mode]

VPH

FUSE BLOWING

No Yes

VPL VPL VPL VPL VPL

User generated transition

Internally generated transition

SENS.

Programming State Machine

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

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 regis-

ters 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.

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 program-

ming of any bits in the device.

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

This register wraps by default. This means that sending addi-

tional 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 quan-

tity of VPL pulses, send one VPH pulse on the VOUT pin.

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 operat-

ing 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

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 coef-

ficient 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)

To select a register, increment through the register bitfields by

sending VPL pulses on the VOUT pin. Note that the program-

ming 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.

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 incre-

ments by 1 with each VPL pulse on the VOUT pin. The param-

eter 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.

Programming Protocol and State Machine Description

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

Programming Logic

Binary Bitfield Address Decimal Equivalent Code Description

QVO Coarse register

00 0 VOUT(Q) mid range

01 1 VOUT(Q) low range

10 2 VOUT(Q) high range

11 3 Register wraps to 00

QVO Fine register

000000000 0 Initial value in selected QVO Coarse range

111111111 511 Maximum value in selected QVO Coarse range

Sens. Coarse register

00 0 Sens low range

01 1 Sens mid range

10 2 Sens high range

11 3 Register wraps to 00

Sens. Fine register

00000000 0 Initial value in selected Sens. Coarse range

11111111 255 Maximum value in selected Sens. Coarse range

TC Register register (See also chart Sensitivity Temperature Coefficient Code Profile in Typical Characteristics section)

00000 0 initial TC

00001 through 01011 1 through 11 Positive TC programming range

01100 through 01111 12 through 15 Unused: equal to codes 4 to 7, respectively

10000 through 11011 16 through 27 Negative TC prgramming range; Value for 16 equals 1 step

less than the value for the Initial TC Value (00000)

11100 through 11111 28 through 31 Unused: equal to codes 20 to 23, respectively

Clamp Bit register

00 0 Rail-to-rail output swing

01 1 0.5 V and VCC– 0.5V rails

10 2 1 V and VCC – 1 V rails

00 3 Register wraps to 00

Polarity Bit register

0 0 Positive (VOUT increases when a positive (south) magnetic

field is applied to the device )

1 1 Negative (VOUT increases when a negative (north) magnetic

field is applied to the device )

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

• A bypass capacitor rated at 0.1µF must be mounted between

the VOUT pin and the GND pin during programming. The

power supply used for programming should be capable of deliv-

ering 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

Programming Guidelines

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. Polarity

b. TC Register

c. Sens Coarse

d. QVO Coarse

e. Sens Fine

g. 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 Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

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Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

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.

Programming Example

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.

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

Package KB, 3-Pin SIP

.208

.203

5.28

5.16

.063

.059

1.60

1.50

3.51

3.38

.138

.133

.600

.560

15.25

14.24

.023

.018

0.58

0.46

.0189

.0142

0.48

0.36

.0173

.0138

0.44

0.35

.085

MAX

2.16

.020

REF

0.51

.030

REF

0.75

.075

BSC

1.91

.0165

NOM

.042

.033

REF

0.84

45°

BSC

45°

BSC

Dimensions in inches

Metric dimensions (mm) in brackets, for reference only

231

Dambar removal protrusion

Hall element Active Area Depth

Leads 1 and 3 only

A1373-DS Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

High Precision, Output Pin Programmable, Linear Hall Effect Sensors

A1373 and A1374

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 de par tures from the detail spec i fi ca tions as may be required

to permit improvements in the per for mance, reliability, or manufactur-

ability 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 sys tems without express written approval.

The in for ma tion in clud ed herein is believed to be ac cu rate and reliable.

How ev er, Allegro MicroSystems, Inc. assumes no re spon si bil i ty for its

use; nor for any in fringe ment of patents or other rights of third parties

which may result from its use.