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Teilenummer | A1142LLH |
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Beschreibung | Sensitive Two-Wire Chopper-Stabilized Unipolar Hall-Effect Switches | |
Hersteller | Allegro MicroSystems | |
Logo | ||
Gesamt 11 Seiten A1140/41/42/43
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall-Effect Switches
Package LH, 3-pin SOT
3
1. VCC
2. No connection
3. GND
NC
12
Package UA, 3-pin SIP
1. VCC
2. GND
3. GND
PTCT
123
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC .......................................... 28 V
Reverse-Supply Voltage, VRCC ........................ –18 V
Magnetic Flux Density, B .........................Unlimited
Operating Temperature
Ambient, TA, Range E.................. –40ºC to 85ºC
Ambient, TA, Range L................ –40ºC to 150ºC
Maximum Junction, TJ(max)........................165ºC
Storage Temperature, TS .................. –65ºC to 170ºC
The A1140, A1141, A1142, and A1143 devices are sensitive, two-wire, unipo-
lar, Hall effect switches that are factory-programmed at end-of-line to optimize
magnetic switchpoint accuracy. These devices are produced on the Allegro
MicroSystems advanced BiCMOS wafer fabrication process, which implements a
patented, high-frequency, chopper-stabilization technique that achieves magnetic
stability and eliminates the offsets that are inherent in single-element devices
exposed to harsh application environments. Commonly found in a number of
automotive applications, the A1140-43 family of devices are utilized to sense: seat
track position, seat belt buckle presence, hood/trunk latching, and shift selector
position.
Two-wire unipolar switches are particularly advantageous in price-sensitive appli-
cations, because they require one less wire than the more traditional open-collec-
tor output switches. Additionally, the system designer gains inherent diagnostics
because output current normally flows in either of two narrowly-specified ranges.
Any output current level outside of these two ranges is a fault condition. The
A1140-43 family of devices also features on-chip transient protection, and a Zener
clamp to protect against overvoltage conditions on the supply line.
The output currents of the A1141 and A1143 switch HIGH in the presence of a south
polarity magnetic field of sufficient strength; and switch LOW otherwise, including
when there is no significant magnetic field present. The A1140 and A1142 have
inverted output current levels: switching LOW in the presence of a south polarity
magnetic field of sufficient strength, and HIGH otherwise. The devices also differ in
their specified LOW current supply levels.
All family members are offered in two package styles: SOT-23W, a miniature low-
profile package for surface-mount applications (suffix –LH), and TO-92, three-
lead ultra-mini Single Inline Package (SIP) for through-hole mounting
(suffix –UA).
Field-programmable versions are also available. Refer to: A1180, A1181, A1182,
and A1183.
Features and Benefits
Chopper stabilization
Low switchpoint drift over operating tem-
perature range
Low stress sensitivity
Factory programmed at end-of-line for
optimized switchpoints
On-chip protection
Supply transient protection
Reverse-battery protection
On-board voltage regulator
3.5 V to 24 V operation
A1140-DS
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
A1140/41/42/43
Sensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches
Functional Description
Operation
The output, ICC, of the A1140 and A1142 devices switch low
after the magnetic field at the Hall sensor exceeds the oper-
ate point threshold, BOP. When the magnetic field is reduced to
below the release point threshold, BRP, the device output goes
high. The differences between the magnetic operate and release
point is called the hysteresis of the device, BHYS. This built-
in hysteresis allows clean switching of the output even in the
presence of external mechanical vibration and electrical noise.
The A1141 and A1143 devices switch with opposite polarity for
similar BOP and BRP values, in comparison to the A1140 and
A1142 (see figure 1).
I+
ICC(H)
I+
ICC(H)
0
B–
ICC(L)
B+
0
B–
ICC(L)
B+
BHYS
(A) A1140, A1142
BHYS
(B) A1141, A1143
Figure 1. Alternative switching behaviors are available in the A114x device family. On the horizontal axis, the B+ direction indicates
increasing south polarity magnetic field strength, and the B– direction indicates decreasing south polarity field strength (including the
case of increasing north polarity).
A1140-DS
Allegro MicroSystems, Inc.
6
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
6 Page | ||
Seiten | Gesamt 11 Seiten | |
PDF Download | [ A1142LLH Schematic.PDF ] |
Teilenummer | Beschreibung | Hersteller |
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