A1421 View Datasheet(PDF) - Allegro MicroSystems
Part Name
Description
MFG CO.
A1421
Allegro MicroSystems
'A1421' PDF : 15 Pages View PDF
A1421, A1422,
and A1423
High Precision Hall Effect AC-Coupled Differential
Sensor IC with Integrated Filter Capacitor
in the Characteristic Data section quantify the effect of the input
signal amplitude on the phase shift of the output. Positive values
of delay indicate a lagging output, while negative values indicate
a leading output.
AC-Coupled Operation
Steady-state magnet and system offsets are eliminated using an
on-chip differential bandpass filter. The upper and lower cut-off
frequencies of this patented filter are set using an internal inte-
grated capacitor. The differential structure of this filter improves
the ability of the IC to reject single-ended noise on the GND
or VCC lines and, as a result, makes the device more resistant
to EMI (electromagnetic interference) typically seen in hostile
remote-sensing environments.
Power Supply Protection
The device contains an on-chip voltage regulator and can operate
over a wide supply voltage range. In applications that operate the
device from an unregulated power supply, transient protection
must be added externally. For applications using a regulated line,
EMI/RFI protection may still be required. The circuit shown
in figure 3 is the most basic configuration required for proper
device operation.
Typical Circuit
A pull-up resistor, RPU, is required between the supply and out-
put terminals, as shown in figure 3. Also, the auxilliary terminal,
TEST, must be connected externally to the GND terminal.
0.1 uF
1
VCC
A1421, A1422
4
or A1423
2
GND
VOUT
TEST
3
RPU
VS
VOUT
Figure 3. Basic application circuit. A pull-up resistor, RPU, is required
with the output driver.
65.0
Applied Magnetic 15.0
Field, Bdiff
0.0
–15.0
–65.0
BRP(typ)1421
B RP(typ)1422
B RP(typ)1423
B OP(typ)1423
BOP(typ)1421, 1422
1421 Switching State
and Output Signal, VOUT
Off
On
Off
1422 Switching State
and Output Signal, VOUT
On
Off
On
1423 Switching State
and Output Signal, VOUT
On
Off
On
t+
Figure 2. Comparative typical output characteristics. This chart illustrates the switchpoints and the output polarities of the A1421,
A1422, and the A 1423. Characteristics shown without delay, see characteristic data charts for delay and phase shift contributions.
Allegro MicroSystems, Inc.
13
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
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