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Электронный компонент: A1147ELHLT-T

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A1147 and A1148
A1147-DS, Rev. 6
Worcester, Massachusetts 01615-0036 (508) 853-5000
115 Northeast Cutoff, Box 15036
www.allegromicro.com
Allegro MicroSystems, Inc.
AB SO LUTE MAX I MUM RAT INGS
Supply Voltage, V
CC
..........................................28 V
Reverse-Supply Voltage, V
RCC
........................18 V
Magnetic Flux Density, B .........................Unlimited
Power Dissipation, P
D
............................ Graph, p. 5
Operating Temperature
Ambient, T
A
, Range E.................. 40C to 85C
Ambient, T
A
, Range L................ 40C to 150C
Maximum Junction, T
J(max)
........................165C
Storage Temperature, T
S
.................. 65C to 170C
On-chip protection
Supply transient protection
Reverse-battery protection
On-board voltage regulator
3.5 to 24 V operation
Low Current Ultrasensitive Two-Wire Chopper-Stabilized
Unipolar Hall Effect Switches
Package LH, 3-pin SOT
Features and Benefits
The A1147 and A1148 devices are two-wire, unipolar, Hall effect switches that are
factory-programmed at end-of-line to optimize ultrasensitive magnetic switchpoint
accuracy. These devices use a patented high frequency chopper-stabilization tech-
nique, produced using the Allegro advanced BiCMOS wafer fabrication process,
to achieve magnetic stability and to eliminate offset inherent in single-element
devices exposed to harsh application environments.
Commonly found in a number of automotive applications, these switches are
utilized to sense seat track position, seat belt buckle presence, hood/trunk latch-
ing, and shift selector position. Two-wire unipolar switches, such as the A1147
and A1148, are particularly advantageous in price-sensitive applications because
they require one less wire for operation than do switches with the more traditional
open-collector output. Additionally, the system designer inherently gains diagnos-
tics because there is always output current flowing, which should be in either of
two narrow ranges. Any current level not within these ranges indicates a fault con-
dition. These devices also feature on-chip transient protection and a Zener clamp
to protect against overvoltage conditions on the supply line.
The output currents of the A1148 switches HIGH in the presence of a south (+)
polarity magnetic field of sufficient strength, and switches LOW otherwise, as in
the presence of a weak field or a north () polarity field. The A1147 has an oppo-
site output: the currents switch LOW in the presence of a south-polarity magnetic
field of sufficient strength, and switch HIGH otherwise.
Both versions are offered in two package styles. The LH is a SOT-23W, miniature
low-profile package for surface-mount applications. The UA is a three-lead ultra-
mini SIP for through-hole mounting. Each package is available in a lead (Pb) free
version (suffix, T) with 100% matte tin plated leadframe. Field-programmable
versions also available: A1180 and A1181.
Package UA, 3-pin SIP
Chopper stabilization
Low switchpoint drift over operating
temperature range
Low sensitivity to stress
Factory programmed at end-of-line for
optimized switchpoints
1:1
1:1
2
A1147-DS, Rev. 6
Worcester, Massachusetts 01615-0036 (508) 853-5000
115 Northeast Cutoff, Box 15036
www.allegromicro.com
Allegro MicroSystems, Inc.
Low Current Ultrasensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches
A1147 and A1148
NC
1
2
3
Functional Block Diagram
Amp
Regulator
Low-Pass
Filter
GND
VCC
GND
Package UA Only
0.01 uF
V+
Clock/Logic
Dyna
mic
O
ffse
t
Ca
nce
ll
a
t
i
o
n
Sam
p
le
and
H
old
To All Subcircuits
1. VCC
2. No connection
3. GND
1
2
3
1. VCC
2. GND
3. GND
Package LH, 3-pin SOT
Package UA, 3-pin SIP
3
A1147-DS, Rev. 6
Worcester, Massachusetts 01615-0036 (508) 853-5000
115 Northeast Cutoff, Box 15036
www.allegromicro.com
Allegro MicroSystems, Inc.
Low Current Ultrasensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches
A1147 and A1148
ELECTRICAL CHARACTERISTICS
over the operating voltage and temperature ranges, unless otherwise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Supply Voltage
1
V
CC
3.5
24
V
Supply Current
2
I
CCL
B > B
OP
for A1147; B < B
RP
for A1148
2
5
mA
I
CCH
B > B
OP
for A1148; B < B
RP
for A1147
12
17
mA
Reverse Supply Current
I
RCC

V
RCC
= 18 V
1.6
mA
Supply Zener Clamp Voltage
V
ZSUPPLY
I
CC
= I
CCL(max)
+ 3 mA; T
A
= 25C
28
40
V
Supply Zener Clamp Current
3
I
ZSUPPLY
V
ZSUPPLY
= 28 V
8
mA
Output Slew Rate
4
di/dt
Capacitance of the oscilloscope performing
the measurement = 20 pF
36
mA/s
Chopping Frequency
f
C
200
kHz
Power-On Time
5
t
on
C
BYPASS
= 0.01 F
25
s
Power-On State
6,7
POS
t < t
on
;
V
CC
slew rate > 25 mV/s
HIGH
1
V
CC
represents the generated voltage between the VCC pin and the GND pin.
2
Relative values of B use the algebraic convention, where positive values indicate south magnetic polarity, and negative values indicate north magnetic
polarity; therefore greater B values indicate a stronger south polarity field (or a weaker north polarity field, if present).
3
I
ZSUPPLY(max)
= I
CCL(max)
+ 3 mA.
4
Measured without bypass capacitor between VCC and GND. Use of a bypass capacitor results in slower current change.
5
Measured with and without bypass capacitor of 0.01 F. Adding a larger bypass capacitor causes longer Power-On Time.
6
POS is defined as true only with a V
CC
slew rate of 25 mV / s or greater. Operation with a V
CC
slew rate less than 25 mV / s can permanently harm
device performance.
7
POS is undefined for t > t
on
or B
RP
< B < B
OP
.
MAGNETIC CHARACTERISTICS
over the operating voltage and temperature ranges, unless otherwise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.*
Max.
Units
Operate Point
B
OP
A1147 I
CC
= I
CCL
20
37
80
G
A1148 I
CC
= I
CCH
Release Point
B
RP
A1147 I
CC
= I
CCH
10
22
60
G
A1148 I
CC
= I
CCL
Hysteresis
B
HYS
B
HYS
= B
OP
B
RP
5
15
30
G
*Typical data are for initial design estimations only, and assume optimum manufacturing and application conditions, such as T
A
= 25C and V
CC
= 12 V.
Performance may vary for individual units, within the specified maximum and minimum limits.
4
A1147-DS, Rev. 6
Worcester, Massachusetts 01615-0036 (508) 853-5000
115 Northeast Cutoff, Box 15036
www.allegromicro.com
Allegro MicroSystems, Inc.
Low Current Ultrasensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches
A1147 and A1148
Characteristic Data
Supply Current (High) versus Ambient Temperature
at Various Levels of V
CC
(A1147 and A1148)
Supply Current (Low) versus Ambient Temperature
at Various Levels of V
CC
(A1147 and A1148)
Ambient Temperature, T
A
(C)
Ambient Temperature, T
A
(C)
V
CC
3.5 V
12.0 V
24.0 V
V
CC
3.5 V
12.0 V
24.0 V
I
CCL
(mA)
I
CCH
(mA)
0
2
6
8
10
4
50
0
50
100
150
200
50
0
50
100
150
200
50
0
50
100
150
200
Switchpoint Hysteresis versus Ambient Temperature
at Various Levels of V
CC
(A1147 and A1148)
Operate Point versus Ambient Temperature
at Various Levels of V
CC
(A1147 and A1148)
Ambient Temperature, T
A
(C)
Ambient Temperature, T
A
(C)
V
CC
3.5 V
12.0 V
24.0 V
V
CC
3.5 V
12.0 V
24.0 V
B
OP
(G)
B
HYS
(G)
0
10
20
30
50
60
70
40
10
12
16
18
20
14
50
0
50
100
150
200
5
0
10
15
25
30
40
35
20
5
A1147-DS, Rev. 6
Worcester, Massachusetts 01615-0036 (508) 853-5000
115 Northeast Cutoff, Box 15036
www.allegromicro.com
Allegro MicroSystems, Inc.
Low Current Ultrasensitive Two-Wire Chopper-Stabilized Unipolar Hall Effect Switches
A1147 and A1148
THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information
Characteristic
Symbol
Test Conditions*
Value Units
Package Thermal Resistance
R
JA
Package LH, 1-layer PCB with copper limited to solder pads
228
C/W
Package LH, 2-layer PCB with 0.463 in.
2
of copper area each side
connected by thermal vias
110
C/W
Package UA, 1-layer PCB with copper limited to solder pads
165
C/W
*Additional thermal information available on Allegro Web site.
6
7
8
9
2
3
4
5
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
20
40
60
80
100
120
140
160
180
Temperature (C)
Maximum
Allowable
V
CC
(V)
Power Derating Curve
(R
JA
= 228 C/W)
1-layer PCB, Package LH
(R
JA
= 110 C/W)
2-layer PCB, Package LH
(R
JA
= 165 C/W)
1-layer PCB, Package UA
V
CC(min)
V
CC(max)
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
20
40
60
80
100
120
140
160
180
Temperature (C)
P
o
w
e
r
D
i
s
s
i
pa
ti
on
,
P
D
(m
W)
Power Dissipation versus Ambient Temperature
(R
JA
= 165
C/
W)
1-laye
r PCB,
Packag
e UA
(R
JA
= 228
C/W
)
1-lay
er PCB,
Package
LH
(R
JA
=
110
C/W)
2-layer
PCB,
Package
LH