A1391 ALLEGRO [Allegro MicroSystems], A1391 Datasheet - Page 12

• Manufacturer Part Number: A1391
• Description: Micro Power 3 V Linear Hall Effect Sensors withTri-State Output and User-Selectable Sleep Mode
• Manufacturer: ALLEGRO [Allegro MicroSystems]

A1391, A1392,
A1393, and A1395
In figures 4 and 5, the microprocessor supply voltage determines
the ratiometric performance of the A139x output signal. As in the
circuits shown in figures 2 and 3, the device is powered by the
Vbat2 supply, but in this case, ratiometry is determined by the
microprocessor supply, Vbat1.
The S ¯ ¯ L ¯ ¯ E ¯ ¯ E ¯ ¯ P ¯ pin is triggered by the output logic signal from the
microprocessor in figure 5, while in figure 4, the S ¯ ¯ L ¯ ¯ E ¯ ¯ E ¯ ¯ P ¯ pin is
connected to the device power supply pin. Therefore, the device
as configured in figure 4 is constantly in active mode, while
the device as confiugred in figure 5 can be periodically toggled
Figure 4. Application circuit showing ratiometry of V
pin is tied to the microprocessor supply.
Figure 5. Application circuit showing device reference pin, VREF, tied to microprocessor supply. The device
sleep mode also is controlled by the microprocessor.
C
filter
C
Application Circuit with User-Configurable Ratiometry
filter
Vbat 1
Vbat1
Micro Power 3 V Linear Hall Effect Sensors with
Tri-State Output and User Selectable Sleep Mode
I/O
Supply pin
processor
processor
I/O
Supply pin
Micro-
Micro-
I/O
I/O
C
C
bypass
bypass
Vbat2
between the active and sleep modes.
The capacitor C
sible noise transients from the microprocessor supply reaching
the device reference pin, VREF.
It is strongly recommended that an external bypass capacitor be
connected, in close proximity to the A139x device, between the
VCC and GND pins of the device to reduce both external noise
and noise generated by the chopper-stabilization circuits inside of
the A139x.
Vbat2
REF
. Sleep mode is disabled and the VREF
GND
VCC
OUT
GND
VCC
OUT
filter
A139x
is optional, and can be used to prevent pos-
A139x
SLEEP
GND
VREF
115 Northeast Cutoff, Box 15036
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com
SLEEP
GND
VREF
12