A1186 Allegro MicroSystems, A1186 Datasheet - Page 8

• Manufacturer Part Number: A1186
• Description: (A1185 / A1186) Unipolar Hall-Effect Switches
• Manufacturer: Allegro MicroSystems

For additional general application information, visit the Allegro
Web site at www. allegromicro.com.
Typical Application and Programming Circuit
The A118x family of devices MUST be protected by an exter-
nal bypass capacitor, C
VCC, and the ground pin, GND, of the device. C
both external noise and the noise generated by the chopper-sta-
bilization function. As shown in figure 3, a 0.01 μF capacitor
is typical. (For programming the device, a 0.1 μF capacitor is
recommended for proper fuse blowing.)
Installation of C
it to the A118x pins are no greater than 5 mm in length. (For
programming the device, the capacitor may be further away from
the device, including mounting on the board used for program-
ming the device.)
C
high-frequency interferences conducted along the supply lines
A1185-DS, Rev. 1
BYP
Ultrasensitive Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall Effect Switches
serves only to protect the A118x internal circuitry. All
BYP
must ensure that the traces that connect
BYP
, connected between the supply pin,
Figure 3. Typical application circuit
BYP
Application Information
A1185 and A1186
V+
reduces
A
GND
A118x
ECU
VCC
R
SENSE
GND
are passed directly to the load through C
load ECU (electronic control unit) must have sufficient protec-
tion, other than C
A series resistor on the supply side, R
tion with C
When determining the minimum V
device, the voltage drops across R
R
R
code and lock-bit programming, should be done with direct
connections to VCC and GND, with the use of a 0.1uF bypass
capacitor. Programming across the series resistor or sense resis-
tor may not allow enough energy to properly blow the fuses
in the device, as required for proper programming. The result
would be incorrect switchpoints.
SENSE
SENSE
A
B
Package UA Only
Maximum separation 5 mm
B
B
, must be taken into consideration. The typical value for
is approximately 100 Ω. (All programming, including
C
0.01 uF
BYP
BYP
, creates a filter for EMI pulses.
BYP
, installed in parallel with the A118x.
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com
S
CC
and the ECU sense resistor,
S
requirement of the A118x
(not shown), in combina-
BYP
. As a result, the
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