Programmable Linear Hall Effect Sensor ICs with Analog Output

Available in a Miniature Thin Profile Surface Mount Package

A1381, A1382,

A1383, and A1384

11

Allegro MicroSystems, Inc.

115 Northeast Cutoff, Box 15036

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

www.allegromicro.com

Characteristic

Symbol

Notes

Min. Typ. Max. Units

Programming Voltage

Measured at the VOUT pin.

-

-

5.5

V

14

15

16

V

26

27

28

V

Programming Current

Minimum supply current required to ensure proper fuse blowing. In addition, a min-

GND pins during programming to provide the current necessary for fuse blowing.

300

-

-

mA

Pulse Width

30

-

-

μs

5

-

-

μs

30

-

-

μs

15

-

-

μs

30

-

-

μs

Pulse Rise Time

1

-

100

μs

Pulse Fall Time

1

-

100

μs

Overview

Programming is accomplished by sending a series of input volt-

age pulses serially through the VOUT pin of the device. A unique

combination of different voltage level pulses controls the internal

programming logic of the device to select a desired program-

mable parameter and change its value. There are two program-

The 138x features Try mode, Blow mode, and Lock mode:

In Try mode, the value of a single programmable parameter may

•

be set and measured. The parameter value is stored temporar-

ily, and resets after cycling the supply voltage. Note that other

parameters cannot be accessed simultaneously in this mode.

In Blow mode, the value of a single programmable parameter

•

may be permanently set by blowing solid-state fuses internal to

the device. Additional parameters may be blown sequentially.

In Lock mode, a device-level fuse is blown, blocking the fur-

•

ther programming of all parameters.

The programming sequence is designed to help prevent the

device from being programmed accidentally; for example, as a

result of noise on the supply line.

Although any programmable variable power supply can be

used to generate the pulse waveforms, Allegro highly recom-

mends using the Allegro Sensor IC 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.

Definition of Terms

Register. The section of the programming logic that controls the

choice of programmable modes and parameters.

Bit Field. The internal fuses unique to each register, represented

as a binary number. Incrementing the bit field of a particular

register causes its programmable parameter to change, based on

the internal programming logic.

a value expressed as the decimal equivalent of the binary value.

The LSB of a register is denoted as key 1, or bit 0.

Code. The number used to identify the combination of fuses

activated in a bit field, expressed as the decimal equivalent of the

binary value. The LSB of a bit field is denoted as code 1, or bit 0.

Addressing. Incrementing the bit field code of a selected register

by serially applying a pulse train through the VOUT pin of the

device. Each parameter can be measured during the addressing

process, but the internal fuses must be blown before the program-

ming code (and parameter value) becomes permanent.

blowing a fuse internal to the device. Once a bit (fuse) has been

blown, it cannot be reset.

Cycling the Supply. Powering-down, and then powering-up the

supply voltage. Cycling the supply is used to clear the program-

ming settings in Try mode.

Programming Guidelines