A1225, A1227, and A1229
Hall Effect Latch for High Temperature Operation
Features and Benefits
▪
Symmetrical switchpoints
▪
Superior temperature stability
▪
Operation from unregulated supply
▪
Open-drain 25 mA output
▪
Reverse Battery protection
▪
Activate with small, commercially available
permanent magnets
▪
Solid-state reliability
▪
Small size
▪
Resistant to physical stress
▪
Enhanced ESD structures result in 8 kV HBM ESD
performance without external protection components
▪
Internal protection circuits enable 40 V load dump
compliance without external protection components
Description
These Hall-effect latches are extremely temperature-stable
and stress resistant sensor ICs especially suited for operation
over extended temperature ranges to 150°C. Superior high-
temperature performance is made possible through a novel
Schmitt trigger circuit that maintains operate and release
point symmetry by compensating for temperature changes
in the Hall element. Additionally, internal compensation
provides magnetic switchpoints that become more sensitive
with temperature, hence offsetting the usual degradation of
the magnetic field with temperature. The symmetry capability
makes these devices ideal for use in pulse-counting applications
where duty cycle is an important parameter. The three basic
devices (A1225, A1227, and A1229) are identical except for
magnetic switchpoints.
Each device includes on a single silicon chip a voltage regulator,
Hall-voltage generator, temperature compensation circuit,
signal amplifier, Schmitt trigger, and a buffered open-drain
output to sink up to 25 mA. The on-board regulator permits
operation with supply voltages of 3.8 to 24 V.
The first character of the part number suffix determines the
device operating temperature range. Suffix L is for –40°C to
150°C. Two package styles provide a magnetically optimized
package for most applications. Suffix LT is a miniature SOT89/
TO-243AA transistor package for surface-mount applications,
suffix UA is a three-lead ultra-mini-SIP. Both packages are lead
(Pb) free with 100% matte tin leadframe plating.
Packages:
3-pin SIP
(suffix UA)
3-pin SOT89
(suffix LT)
Not to scale
Functional Block Diagram
VCC
Regulator
To All Subcircuits
Clock / Logic
VOUT
Hall Chopping Logic
AMP
Anti-aliasing
LP-Filter
Tuned Filter
GND
A1225-DS, Rev. 1
A1225, A1227
and
A1229
Hall Effect Latch for High Temperature Operation
Selection Guide
Part Number
A1225LLTTR-T
A1225LUA-T
A1227LLTTR-T
A1227LUA-T
A1229LLTTR-T
A1229LUA-T
Packing
*
7-in. reel, 1000 pieces/reel
Bulk, 500 pieces/bag
7-in. reel, 1000 pieces/reel
Bulk, 500 pieces/bag
7-in. reel, 1000 pieces/reel
Bulk, 500 pieces/bag
Package
3-pin SOT89 surface mount
3-pin SIP through hole
3-pin SOT89 surface mount
3-pin SIP through hole
3-pin SOT89 surface mount
3-pin SIP through hole
Ambient
Temperature, T
A
–40°C to 150°C
–40°C to 150°C
–40°C to 150°C
B
RP
(min)
(G)
–300
–175
–200
B
OP
(max)
(G)
300
175
200
*Contact Allegro
®
for additional packaging options.
Absolute Maximum Ratings
Characteristic
Forward Supply Voltage
Reverse Supply Voltage
Output Off Voltage
Reverse Output Voltage
Continuous Output Current
Operating Ambient Temperature
Maximum Junction Temperature
Storage Temperature
Symbol
V
CC
V
RCC
V
OUT
V
ROUT
I
OUT(SINK)
T
A
T
J
(max)
T
stg
Range L
Notes
Rating
30
–30
30
–0.5
25
–40 to 150
165
–65 to 170
Unit
V
V
V
V
mA
ºC
ºC
ºC
Pin-out Diagrams
Package LT
Package UA
Terminal List Table
Number
1
2
3
Name
VCC
GND
VOUT
Function
Input power supply
Ground
Output signal
1
2
3
1
2
3
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
2
A1225, A1227
and
A1229
Hall Effect Latch for High Temperature Operation
ELECTRICAL CHARACTERISTICS
Valid at T
A
= –40°C to 150°C, C
BYPASS
= 0.1
μF,
V
CC
= 12 V; unless otherwise noted
Characteristics
Electrical Characteristics
Supply Voltage
Supply Current
Supply Zener Voltage
Reverse Battery Current
Power-On Time
3
Power-On State
Chopping Frequency
Output Stage Characteristics
Output Saturation Voltage
Output Leakage Current
Output Rise Time
3,4
Output Fall Time
3,4
Output Zener Voltage
Magnetic Characteristics
A1225
Operate Point
B
OP
A1227
A1229
A1225
Release Point
B
RP
A1227
A1229
A1225
Hysteresis (B
OP
– B
RP
)
B
HYS
A1227
A1229
1
Typical
2
1
Symbol
V
CC
I
CC
V
Z(sup)
I
Z(sup)
t
PO
POS
f
chop
V
OUT(sat)
I
OFF
t
r
t
f
V
Z(out)
I
OUT
= 20 mA
B < B
OP
Test Conditions
Operating; T
J
≤
165°C
B < B
RP
(Output off)
B > B
OP
(Output on)
I
CC
= 9 mA, T
A
= 25°C
V
RCC
= –28 V, T
A
= 25°C
Min.
3.8
–
–
28
–5
–
–
–
–
–
–
–
30
170
140
50
50
100
80
–270
–300
–150
–175
–180
–200
340
280
100
100
200
160
Typ.
1
Max.
24
Unit
2
V
mA
mA
V
mA
μs
–
kHz
mV
μA
ns
ns
V
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
–
–
–
–
–
HIGH
400
175
<1
200
200
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
6
6
–
–
12
–
–
400
10
2000
2000
–
270
300
150
175
180
200
–170
–140
–50
–50
–100
–80
540
600
300
350
360
400
V
OUT
= 24 V, B < B
RP
R
L
= 820
Ω,
C
L
= 20 pF
R
L
= 820
Ω,
C
L
= 20 pF
I
OUT
= 3 mA, T
A
= 25°C
T
A
= 25°C
Over operating temperature range
T
A
= 25°C
Over operating temperature range
T
A
= 25°C
Over operating temperature range
T
A
= 25°C
Over operating temperature range
T
A
= 25°C
Over operating temperature range
T
A
= 25°C
Over operating temperature range
T
A
= 25°C
Over operating temperature range
T
A
= 25°C
Over operating temperature range
T
A
= 25°C
Over operating temperature range
data are at T
A
= 25°C and V
CC
= 12 V, and are for design estimations only.
G (gauss) = 0.1 mT (millitesla).
3
Minimum and maximum specifications verified by bench characterization and not guaranteed by Allegro final test.
4
C = oscilloscope probe capacitance.
L
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
3
A1225, A1227
and
A1229
Hall Effect Latch for High Temperature Operation
THERMAL CHARACTERISTICS
may require derating at maximum conditions, see application information
Characteristic
Package Thermal Resistance
Symbol
R
θJA
Test Conditions*
Package LT, 1-layer PCB with copper limited to solder pads
Package LT, 2-layer PCB with 0.94 in
2
copper each side
Package UA, 1-layer PCB with copper limited to solder pads
*Additional thermal information available on Allegro website.
Value
180
78
165
Units
ºC/W
ºC/W
ºC/W
Power Derating Curve
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
20
40
V
CC(max)
Maximum Allowable V
CC
(V)
1-layer PCB, Package LT
(R
θJA
= 180 ºC/W)
1-layer PCB, Package UA
(R
θJA
= 165 ºC/W)
2-layer PCB, Package LT
(R
θJA
= 78 ºC/W)
V
CC(min)
60
80
100
120
140
160
180
T
A
(ºC)
Power Dissipation
1900
1800
1700
1600
1500
1400
1300
1200
1100
1000
900
800
700
600
500
400
300
200
100
0
20
Power Dissipation, P
D
(m W)
2
(R -lay
θ
J
A
1-la
(R yer P
CB
θ
JA
=
165 , Pac
1-la
ºC/ kage
W)
(R yer P
UA
CB
θ
JA
=
, Pa
180
ºC/ ckage
W)
LT
er
= PC
78 B
ºC , Pa
/W ck
) ag
e
LT
40
60
80
100
120
Temperature (°C)
140
160
180
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
4
A1225, A1227
and
A1229
Hall Effect Latch for High Temperature Operation
Characteristic Performance
A1225, A1227, and A1229 Electrical Characteristics
Average Supply Current (On) versus Ambient Temperature
6.0
5.5
5.0
4.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
- 40
- 20
0
20
40
60
80
100 120 140 160
2
6
10
14
18
22
26
Average Supply Current (On) versus Supply Voltage
I
CC(av)
(mA)
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
- 60
V
CC
(V)
3.8
4.5
12
24
I
CC(av)
(mA)
T
A
(°C)
–40
25
150
T
A
(°C)
V
CC
(V)
Average Supply Current (Off) versus Ambient Temperature
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
- 60
- 40
- 20
0
20
40
60
80
100 120 140 160
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
Average Supply Current (Off) versus Supply Voltage
I
CC(av)
(mA)
3.8
4.5
12
24
I
CC(av)
(mA)
V
CC
(V)
T
A
(°C)
–40
25
150
2
6
10
14
18
22
26
T
A
(°C)
V
CC
(V)
Average Output Saturation Voltage versus Ambient Temperature
300
250
Average Output Saturation Voltage versus Supply Voltage
300
250
V
OUT(sat)
(mV)
V
OUT(sat)
(mV)
200
150
100
50
0
- 60
- 40
- 20
0
20
40
60
80
100 120 140 160
V
CC
(V)
3.8
4.5
12
24
200
150
100
50
0
2
6
10
14
18
22
26
T
A
(°C)
–40
25
150
T
A
(°C)
V
CC
(V)
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
5
