Programmable, Chopper-Stabilized,

Two Wire Hall-Effect Switches

A1190, A1192,

and A1193

11

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Try Mode In Try mode, bit field addressing is accomplished by

shown in figure 6. Each pulse increases the bit field value for the

selected parameter, increasing by one on the falling edge of each

called the code. Addressing activates the corresponding fuse

locations in the given bit field by increasing the binary value of

an internal DAC, up to the maximum possible code. As the value

of the bit field code increases, the value of the programmable

pulse to determine if the required result for the programmable

parameter has been reached. Cycling the supply voltage resets

all the locations in the bit field that have un-blown fuses to their

initial states.

values can be traversed from low to high, or from high to low. To

accommodate this direction selection, the value of the bit field

(and code) defaults to the value 1, on the falling edge of the final

provided in figure 11.

Blow Mode After the required code is determined for a given

parameter, its value can be set permanently by blowing individual

fuses in the appropriate register bit field. Blowing is accom-

plished by selecting the register, then the Blow mode selection

key, followed by the appropriate bit field address, and ending

the sequence with the Blow pulse. The Blow mode selection key

complete example is provided in figure 12.

internal to the device. Due to power requirements, the fuse for

each bit in the bit field must be blown individually. The A119x

family built-in circuitry allows only one fuse at a time to be

blown. During Blow mode, the bit field can be considered a “one-

the binary and decimal values for Blow mode bit field address-

ing. It should be noted that the simple relationship between the

state of decimal code 0 (binary 000000).

Figure 6. Try mode bit field addressing pulses

Figure 7. Example of code 5 broken into its binary components

0

Table 3. Blow Mode Bit Field Addressing

Quantity of

Binary Register

Setting

Equivalent Code

1

000001

1

2

000010

2

3

000100

4

4

001000

8

5

010000

16

6

100000

32

(Decimal Equivalent)

Code 5

Bit Field Selection

Address Code Format

Code in Binary

Fuse Blowing

Target Bits

Fuse Blowing

Address Code Format

(Binary)

1 0 1

Bit 2

Bit 0

Code 4

Code 1

(Decimal Equivalents)

0

Key

Figure 5. Register selection pulse sequence