A1391SEHLT-T Allegro, A1391SEHLT-T Datasheet - Page 11

• Manufacturer Part Number: A1391SEHLT-T
• Manufacturer: Allegro

A1391, A1392,
A1393, and A1395
Figures 2 and 3 present applications where the VCC pin is con-
nected together with the VREF pin of the A139x. Both of these
pins are connected to the battery, Vbat2. In this case, the device
output will be ratiometric with respect to the battery voltage.
The only difference between these two applications is that the
S ¯ ¯ L ¯ ¯ E ¯ ¯ E ¯ ¯ P ¯ pin in figure 2 is connected to the Vbat2 potential, so the
device is always in the active mode. In figure 3, the S ¯ ¯ L ¯ ¯ E ¯ ¯ E ¯ ¯ P ¯ pin is
toggled by the microprocessor; therefore, the device is selectively
and periodically toggled between active mode and sleep mode.
Figure 2. Application circuit showing sleep mode disabled and output ratiometirc to the
A139x supply.
Figure 3. Application circuit showing microprocessor-controlled sleep mode and output ratiome-
tirc to the A139x supply.
Vbat1
Vbat1
Device Supply Ratiometry Application Circuit
Micro Power 3 V Linear Hall Effect Sensors with
Tri-State Output and User Selectable Sleep Mode
Supply pin
I/O
Supply pin
I/O
processor
Micro-
processor
Micro-
C
I/O
C
I/O
bypass
bypass
Vbat2
Vbat2
In both figures, the device output is connected to the input of an
A-to-D converter. In this configuration, the converter reference
voltage is Vbat1.
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.
GND
GND
VCC
OUT
VCC
OUT
A139x
A139x
SLEEP
SLEEP
GND
VREF
GND
VREF
115 Northeast Cutoff, Box 15036
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com
11