A1181 Datasheet, PDF (6/14 Pages) Allegro MicroSystems – Two-Wire, Programmable, Chopper-Stabilized, Unipolar Hall-Effect Switch

TWO-WIRE, PROGRAMMABLE, UNIPOLAR HALL-EFFECT SWITCH FAMILY
(PRELIMINARY INFORMATION – SUBJECT TO CHANGE)
PROGRAMMING PROTOCOL
The operate points are programmed by serially addressing the devices through the supply terminal V_CC (pin 1). After the
correct operate point is determined, the device programming bits are permanently blown, and a locking bit is blown to
prevent any further programming.
Switch Point Program Enable. To program the device, a keying sequence is used to activate / enable the addressing
mode as shown in Figure 1. This sequence consisting of a VPP pulse, one VPH pulse, and a VPP pulse with no supply
interruptions, is designed to prevent the device from being programmed accidentally (e.g., as a result of noise on the
supply line).
Figure 1. Program Enable Pulse Sequence.
Valid over operating temperature range unless otherwise noted.
Part Number
Characteristics
PROGRAMMING PROTOCOL (T_A = +25 °C)
Programming Voltage⁶
Programming Current
A118X Family
Pulse width
Pulse Rise Time
Pulse Fall Time
Symbol
Test Conditions
Min.
V_PL
Minimum voltage range
during programming
4.5
V_PH
11.5
V_PP
25
I_PP
t_r = 11us, 5V→26V,
C_bypass = 0.1uF
-
t_d(0) OFF time between bits
20
Pulse duration for enable
t_d(1) and addressing
20
sequences
t_dP
Pulse duration for fuse
blowing
100
t_r
V_PL to V_PH or V_PP
5
t_f
V_PH or V_PP to V_PL
5
Limits
Typ. Max.
Units
5
5.5
V
12.5 13.5
V
26
27
V
190
-
mA
-
-
µs
-
-
µs
300
-
µs
-
100
µs
-
100
µs
6 _{Programming Voltages are measured at Pin #1 (Vcc) of SIP. A minimum capacitance of 0.1uF must be connected from Vcc to GND of the SIP to}
provide the current necessary to blow the fuse.
Rev. 1.8 25 April 2003
Page 6
115 Northeast Cutoff, Box 15036
Worcester, Massachus etts 01615-0036 [phone]
Copyright © 1993, 1995 Allegro MicroSystems, Inc.