a1181 Allegro MicroSystems, Inc., a1181 Datasheet - Page 7

• Manufacturer Part Number: a1181
• Description: Two-wire, Programmable, Chopper-stabilized, Unipolar Hall-effect Switch Microsystems
• Manufacturer: Allegro MicroSystems, Inc.

Addressing.
sequentially selected (Figure 2) until the required operate point is reached. Note that the difference between Bop and the
magnetic release point (Brp), the Hysteresis (Hys), is fixed for all addresses.
Code Programming. After the desired switch point address is selected (0 through 31), each bit of the corresponding
binary address should be programmed individually, not at the same time. For example, to program code 5 (binary
000101), bits 1 (code 1) and bit 3 (code 4) need to be programmed. Bit programming is accomplished by addressing the
code and applying a V
in Figure 3.
Lock-Bit Programming. After the desired code is programmed, the lock bit, or code 32, can be programmed (figure 4) to
prevent further programming of the device.
See Allegro website at
programming products. Programming hardware is available for purchase and programming software is available for free.
TWO-WIRE, PROGRAMMABLE, UNIPOLAR HALL-EFFECT SWITCH FAMILY
Rev. 1.8 25 April 2003
The magnetic operate point (Bop) is adjustable using 5 bits or 31 addresses. The 31 addresses are
Page 7
(PRELIMINARY INFORMATION – SUBJECT TO CHANGE)
PP
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pulse, the programming is not reversible. An appropriate sequence for blowing code 5 is shown
…PROGRAMMING PROTOCOL CONT INUED
V
V
0
PL
PH
Figure 2. Sequential selected addresses.
t
d(1)
Figure 4. Lock-bit programming
Figure 3. Bit programming.
for extensive information on device programming as well as
t
d(0)
115 Northeast Cutoff, Box 15036
Worcester, Massachus etts 01615-0036 [phone]
Copyright © 1993, 1995 Allegro MicroSystems, Inc.