The A3425LK dual Hall-effect switch is an extremely
temperature-stable and stress-resistant sensor especially suited for use in
digital-encoder systems in the harsh environments of automotive or
industrial applications over extended temperature ranges to +150°C.
Superior high-temperature performance is made possible through
dynamic offset cancellation, which reduces the residual offset voltage
normally caused by device overmolding, temperature dependencies, and
thermal stress. This device also eliminates the major manufacturing
hurdles encountered in fine-pitch direction-detection applications,
namely maintaining accurate mechanical location between the two active
Hall elements. Here, the two Hall elements are photolithographically
aligned to better than 1 µm, as contrasted with 100 µm or worse me-
chanical location tolerance when manufactured discretely. The
A3425LK is an ultra-sensitive device optimized for use with high-
density ring magnets.
The device includes on a single silicon chip a voltage regulator, two
independent chopper-stabilized Hall-voltage generators , two small-
signal amplifiers, two Schmitt triggers, and two short-circuit protected
open-collector outputs to sink up to 30 mA each. An on-board regulator
permits operation with supply voltages of 3.3 to 26.5 volts. With
suitable output pull ups, it can be used directly with bipolar or MOS
logic circuits.
The A3425LK dual Hall-effect switch is supplied in a 4-pin plastic
SIP for operation over a temperature range of -40°C to +150°C. A
similar device, with on-chip logic processing specifically for direction
detection applications, in a 5-pin SIP, is the A3422LKA.
FEATURES
a73 Two Matched Hall Switches On A Single Substrate
a73 1 mm Sensor-to-Sensor Spacing
a73 Superior Temperature Stability
a73 Resistant to Physical Stress
a73 Output Short-Circuit Protection
a73 Operation From Unregulated Supply
a73 Reverse Battery Protection
a73 Solid-State Reliability
a73 Integrated ESD Protection on Outputs and Supply
Data Sheet
27651.20
PRELIMINARY INFORMATION
(subject to change without notice)
August 21, 2000
Pinning is shown viewed from branded side.
DUAL, CHOPPER-STABILIZED, ULTRA-SENSITIVE,
BIPOLAR HALL-EFFECT SWITCH
3425
ABSOLUTE MAXIMUM RATINGS
at T
A
= +25°C
Supply Voltage, V
CC
........................ 26.5 V
Reverse Battery Voltage, V
RCC
.......... -18 V
Zener Current, I
Z
............................ 100 mA
Magnetic Flux Density, B...........Unlimited
Output Off Voltage, V
OUT
.................... V
CC
Output Current, I
OUT
........................ 30 mA
Reverse Output Current, I
OUT
........ -50 mA
Package Power Dissipation, P
D
. See Graph
Junction Temperature, T
J
............... +170°C
Operating Temperature Range,
T
A
, ............................ -40°C to +150°C
Storage Temperature Range,
T
S
.............................. -65°C to +170°C
Always order by complete part number, e.g., A3425LK .
Dwg. PH-017
1
SUPPLY
V
CC
4
GROUND
32
X
OUTPUT
2
OUTPUT
1
X