A3150: Programmable, Chopper-Stabilized, Hall-Effect Switch

Data Sheet
27621.40
3150
PROGRAMMABLE, CHOPPERSTABILIZED, HALL-EFFECT SWITCH
X
The A3150JLT and A3150JUA programmable switches provide
tooth/valley recognition in large gear-tooth sensing applications. Each
device consists of a single element, chopper-stabilized Hall-effect IC
that can be programmed to the desired magnetic switch point, optimizing device airgap and timing accuracy performance after final
packaging. The small package can be easily assembled and used in
conjunction with a wide variety of gear/target shapes and sizes. The
two devices differ only in package style.
PTCT
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R 0
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S OR 25
I
D F A3
— se
U
1
2
3
GROUND
OUTPUT
CC
SUPPLY
V
Dwg. PH-003-2
PRELIMINARY INFORMATION
(subject to change without notice)
April 12, 1999
ABSOLUTE MAXIMUM RATINGS
at TA = 25°C
Supply Voltage, VCC ........................... 26.5 V
Reverse Supply Voltage, VRCC ............ -30 V
Overvoltage Supply Current, ICC ..... 100 mA
Magnetic Flux Density, B ............ Unlimited
Output Current, IOUT ..... Internally Limited
Output OFF Voltage, VOUT ................. 26.5 V
Reverse Output Current, IROUT ......... -50 mA
Operating Temperature Range,
TA ............................... -40°C to +115°C
Storage Temperature, TS ................... +170°C
The technology used for this deviceis Hall-effect based.
The device incorporates a single-element Hall IC that switches in
response to magnetic signals created by a ferrous target. The programmability of the circuit eliminates magnet and system offsets such as
those caused by tilt yet provides zero-speed detection capabilities
without the associated running jitter inherent in classical digital solutions.
A proprietary dynamic offset cancelation technique, with an
internal high-frequency clock, reduces the residual offset voltage,
which is normally caused by device overmolding, temperature
dependancies, and thermal stress. This technique produces devices that
have an extremely stable quiescent output voltage, are immune to
mechanical stress, and have precise recoverability after temperature
cycling. Many problems normally associated with low-level analog
signals are minimized by having the Hall element and amplifier in a
single chip. Output precision is obtained by internal gain adjustments
during the manufacturing process and operate-point programming in the
user’s application.
This system is ideal for use in gathering speed, position, and
timing information using gear-tooth-based configurations. The
A3150JLT/JUA are particularly suited to those applications that require
accurate duty cycle control or accurate edge detection. The lower
vibration sensitivity also makes these devices extremely useful for
transmission speed sensing applications.
Continued next page
Always order by complete part number: the prefix 'A' + the basic four-digit
part number + a suffix to indicate operating temperature range +
a suffix to indicate package style, e.g., A3150JLT .
3150
PROGRAMMABLE, CHOPPERSTABILIZED, PRECISION,
HALL-EFFECT SWITCH
FUNCTIONAL BLOCK DIAGRAM
1
SUPPLY
REG.
LOW-PASS
FILTER
OFFSET
ADJUST
SAMPLE
& HOLD
X
DYNAMIC
OFFSET CANCELLATION
PROGRAM
LOGIC
POWER-UP
OUTPUT
3
CONTROL
CURRENT
LIMIT
<1Ω
GROUND
2
Dwg. FH-020-3
Two package styles provide a magnetically optimized package for most applications. Suffix ‘–LT’ is a
miniature SOT-89/TO-243AA transistor package for
surface-mount applications; while suffix ‘–UA’ is a
three-lead ultra-mini-SIP for through-hole mounting.
FEATURES AND BENEFITS
■ Chopper Stabilized for
Extremely Low Switch-Point Drift and
Immunity to Mechanical Stress
■ Externally Programmed Switch Point
■ On-Chip Supply-Transient Protection
■ Output Short-Circuit Protection
■ Single-Chip IC for High Reliability
■ Small Mechanical Size
■ <50 µs Power-On Time
■ Wide Operating Voltage Range
■ Defined Power-On State
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2000, Allegro MicroSystems, Inc.
3150
PROGRAMMABLE, CHOPPERSTABILIZED, PRECISION,
HALL-EFFECT SWITCH
ELECTRICAL CHARACTERISTICS over operating voltage and temperature range (unless
otherwise noted).
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Supply Voltage
VCC
Operating, TJ < 165°C
4.25
–
26
V
Power-On State
POS
After programming, VCC = 0 → 5 V
HIGH
HIGH
HIGH
–
Low Output Voltage
VOUT(SAT)
IOUT = 20 mA
–
175
400
mV
Output Current Limit
IOUTM
VOUT = 12 V
65
80
95
mA
Output Leakage Current
IOFF
VOUT = 24 V
–
0.2
10
µA
Supply Current
ICC
Before programming, output OFF
–
4.0
7.0
mA
Before programming, output ON
–
5.0
8.0
mA
VRCC = -30 V
–
–
-5.0
mA
Reverse Supply Current
IRCC
Power-On Delay
ton
VCC > 5 V
–
20
50
µs
Output Rise Time
tr
RL = 820 Ω, CL = 20 pF
–
200
–
ns
Output Fall Time
tf
RL = 820 Ω, CL = 20 pF
–
100
–
ns
Clock Frequency
fC
–
340
–
kHz
Zener Voltage
VZ
IZT = 100 µA, TA = 25°C
27
32
–
V
Zener Impedance
zz
IZT = 10 mA, TA = 25°C
–
50
100
Ω
NOTE: Typical data is at VCC = 5 V and TA = +25°C and is for design information only.
MAGNETIC CHARACTERISTICS over operating supply voltage and temperature ranges.
Limits
Characteristic
Symbol
Operate Point
BOP
∆BOP
Hysteresis
Test Conditions
Min.
Typ.
Max.
Units
Programmable offset range
500
670
850
G
Initial (before programming)
0
20
40
G
Resolution
8.0
11
14
G
VCC = 14 V, after programming, BOP ≈ 500 G
-35
8.0
+35
G
5.0
20
35
G
Bhys
NOTE: Typical data is at VCC = 5 V and TA = +25°C and is for design information only.
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3150
PROGRAMMABLE, CHOPPERSTABILIZED, PRECISION,
HALL-EFFECT SWITCH
TYPICAL ELECTRICAL CHARACTERISTICS
5.0
10
T A = +25°C
SUPPLY CURRENT IN mA
V CC = 5 V
B > B OP
SUPPLY CURRENT IN mA
4.0
3.0
B < B RP
8.0
6.0
B > B OP
4.0
B < B RP
2.0
2.0
1.0
0
-50
-25
0
25
50
75
100
AMBIENT TEMPERATURE IN °C
125
150
Dwg. GH-053-2
0
5
10
15
20
25
SUPPLY VOLTAGE IN VOLTS
Dwg. GH-041-2
300
I OUT = 20 mA
SATURATION VOLTAGE IN mV
V CC = 4.5–24 V
200
100
0
-50
-25
0
25
50
75
100
125
150
AMBIENT TEMPERATURE IN °C
Dwg. GH-040-4
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
3150
PROGRAMMABLE, CHOPPERSTABILIZED, PRECISION,
HALL-EFFECT SWITCH
FUNCTIONAL DESCRIPTION
Chopper-Stabilized Technique. These devices use a
proprietary dynamic offset cancellation technique, with an
internal high-frequency clock to reduce the residual offset
voltage of the Hall element that is normally caused by device
overmolding, temperature dependencies, and thermal stress.
This technique produces devices that have an extremely stable
quiescent Hall output voltage, are immune to thermal stress, and
have precise recoverability after temperature cycling. This
technique will also slightly degrade the device output repeatability.
SAMPLE
& HOLD
REG
X
B
+V
The Hall element can be considered as a resistor array
similar to a Wheatstone bridge. A large portion of the offset is a
result of the mismatching of these resistors. The chopperstabilizing technique cancels the mismatching of the resistors by
changing the direction of the current flowing through the Hall
plate and Hall voltage measurement taps, while maintaining the
Hall-voltage signal that is induced by the external magnetic flux.
The signal is, then, captured by a sample-and-hold circuit.
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+V
OUTPUT VOLTAGE
VCC
B RP
B OP
VOUT(SAT)
0
0
+B
FLUX DENSITY
Dwg. GH-007-2
SUPPLY
3
OUTPUT
2
1
CC
0.1 µF
V
The simplest form of magnet that will operate these devices
is a bar magnet with the south-seeking pole towards the branded
surface of the device. Many other methods of operation are
possible. Extensive applications information on magnets and
Hall-effect devices is also available in the Allegro Electronic
Data Book AMS-702 or Application Note 27701, or
+
Dwg. AH-011-2
PTCT
Applications. It is strongly recommended that an external
bypass capacitor be connected (in close proximity to the Hall
element) between the supply and ground of the device to reduce
both external noise and noise generated by the chopper-stabilization technique.
HALL
VOLTAGE
X
Operation. The output of these devices switches low (turns
ON) when a magnetic field (south pole) perpendicular to the
Hall element exceeds the operate point threshold (BOP). After
turn-ON, the output is capable of sinking 25 mA and the output
voltage is VOUT(SAT). When the magnetic field is reduced below
the release point (BRP), the device output goes high (turns OFF).
The difference in the magnetic operate and release points is the
hysteresis (Bhys) of the device. This built-in hysteresis allows
clean switching of the output even in the presence of external
mechanical vibration and electrical noise.
Dwg. EH-012
—
SUPPLY
Dwg. EH-013
3150
PROGRAMMABLE, CHOPPERSTABILIZED, PRECISION,
HALL-EFFECT SWITCH
PROGRAMMING PROTOCOL
The A3150JLT and A3150JUA operate points are programmed by serially addressing the device through the
supply terminal (pin1). After the correct operate point is
determined, the device programming bits are selected and
then a “lock” set to prevent any further (accidental)
programming.
Program Enable. To program the device, a sequence of
pulses is used to activate/enable the addressing mode as
shown in figure 1. This sequence of a VPP pulse, at least
seven VPH pulses, and a VPP pulse with no supply interruptions, is designed to prevent the device from being programmed accidentally (for example, as a result of noise on
the supply line).
VPP
PROGRAM ENABLE
(AT LEAST 7 PULSES)
VPH
VPL
td(1)
td(1)
td(0)
0
Figure 1 — Program enable
Dwg. WH-013
PROGRAMMING PROTOCOL over operating temperature range.
Limits
Characteristic
Programming Voltage
Symbol
Description
Min.
Typ.
Max.
Units
Minimum voltage during programming
4.5
5.0
5.5
V
VPH
9.0
10
11
V
VPP
20
23
25
V
VPL
Programming Current
IPP
Max. supply current during programming
–
250
–
mA
Pulse Width
td(0)
OFF time between bits
20
–
–
µs
td(1)
Enable, address, program, or lock bit ON time
20
–
–
µs
tdP
Program pulse ON time
100
300
–
µs
Pulse Rise Time
tr
VPL to VPH or VPP
11
–
–
µs
Pulse Fall Time
tf
VPH or VPP to VPL
5.0
–
–
µs
NOTE: Typical data is at TA = +25°C and is for design information only.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
ADDRESS N
(UP TO 63)
ADDRESS N-1
ADDRESS N-2
ADDRESS 2
ADDRESS 0
Address Determination. The operate point is adjustable in 64 increments. With the appropriate target or gear*
in position, the 64 switch points are sequentially selected
(figure 2) until the required operate point is reached. Note
that the difference between the operate point and the
release point (hysteresis) is a constant for all addresses.
ADDRESS 1
3150
PROGRAMMABLE, CHOPPERSTABILIZED, PRECISION,
HALL-EFFECT SWITCH
VPH
VPL
td(1)
td(0)
0
Dwg. WH-014
Set-Point Programming. After the desired set-point
address is determined (0 through 63), each bit of the
equivalent binary address is programmed individually. For
example, as illustrated in figure 3, to program address code
5 (binary 000101), bits 1 and 3 need to be programmed.
Each bit is programmed during the
wide VPP pulse and is not reversible.
Figure 2 — Address determination
VPP
PROGRAM ENABLE
BIT 3 PROGRAM
(000100)
ADDRESS 4
BIT 1 PROGRA
Lock Programming. After the desired set point is
programmed, the program lock is then activated (figure 4)
to prevent further programming of the device.
PROGRAM ENABLE
VPH
VPL
td(1)
td(1)
td(0)
tdP
0
Dwg. WH-015
Figure 3 — Set-point programming
VPP
PROGRAM ENABLE
LOCK PROGRAM
(65 PULSES)
VPH
VPL
td(1)
td(1)
td(0)
tdP
0
Dwg. WH-016
Figure 4 — Lock programming
* In application, the terms “gear” and “target” are often
interchanged. However, “gear” is preferred when motion
is transferred.
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3150
PROGRAMMABLE, CHOPPERSTABILIZED, PRECISION,
HALL-EFFECT SWITCH
CRITERIA FOR DEVICE QUALIFICATION
All Allegro products are subjected to stringent qualification requirements prior to being released to production.
To become qualified, except for the destructive ESD tests, no failures are permitted.
Qualification Test
Test Method and Test Conditions
Test Length
Samples
Biased Humidity (HAST)
T A = 130°C, RH = 85%
50 hrs
77
V CC = VOUT = 5 V
High-Temperature
Operating Life (HTOL)
JESD22-A108,
T A = 150°C, TJ = 165°C
408 hrs
77
VCC = 24 V,
VOUT = 20 V
Accelerated HTOL
JESD22-A108,
TA = 175°C, TJ = 190°C
504 hrs
77
VCC = 24 V,
VOUT = 20 V
Autoclave, Unbiased
JESD22-A102, Condition C,
TA = 121°C, 15 psig
96 hrs
77
High-Temperature
(Bake) Storage Life
MIL-STD-883, Method 1008,
T A = 170°C
1000 hrs
77
Temperature Cycle
MIL-STD-883, Method 1010,
-65°C to +150°C
500 cycles
77
Latch-Up
—
Pre/Post
Reading
6
Electro-Thermally
Induced Gate Leakage
—
Pre/Post
Reading
6
ESD,
Human Body Model
CDF-AEC-Q100-002
Pre/Post
Reading
x per
test
Electrical Distributions
Per Specification
—
30
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Comments
Test to failure,
All leads > TBD
3150
PROGRAMMABLE, CHOPPERSTABILIZED, PRECISION,
HALL-EFFECT SWITCH
ELEMENT LOCATIONS
(±0.005” [0.13 mm] die placement)
Package Designator “LT”
ACTIVE AREA DEPTH
0.030"
0.76 mm
NOM
0.088"
2.24 mm
0.045"
1.14 mm
A
1
2
3
Dwg. MH-008-8
Package Designators “UA” and "UA-TL"
ACTIVE AREA DEPTH
0.018"
0.46 mm
NOM
0.080"
2.04 mm
0.056"
1.44 mm
A
BRANDED
SURFACE
1
2
3
Dwg. MH-011-9A
Although element location is accurate to three sigma for a
particular design, product improvements may result in small
changes to element location.
Allegro
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3150
PROGRAMMABLE, CHOPPERSTABILIZED, PRECISION,
HALL-EFFECT SWITCH
PACKAGE DESIGNATOR 'LT'
(SOT-89/TO-243AA)
Dimensions in Inches
(for reference only)
0.181
0.173
0.072
0.064
0.167
0.155
2
1
Dimensions in Millimeters
(controlling dimensions)
0.063
0.055
3
0.102
0.090
0.0173
0.0138
0.090
0.084
4.25
3.94
0.0189
0.0142
0.0221
0.0173
0.047
0.035
0.059
BSC
4.60
4.40
1.83
1.62
BSC
3.00
BSC
Dwg. MA-009-3A in
Dwg. MA-009-3A mm
2.5
2.0
B
0.031
A
0.102
0.8
2.6
A
4.6
0.181
1
2
2.29
2.13
0.56
0.44
1.50
0.098
0.079
B
2.60
2.29
3
0.44
0.35
0.48
0.36
1.20
0.89
0.118
BSC
2
1
1.60
1.40
3 0.047
1
2
3
1.2
0.028
0.031
0.7
0.8
TYP
TYP
TYP
TYP
ads 1, 2, 3, and A — Standard SOT-89 Layout
ads 1, 2, 3, and B — Low-Stress Version
ads 1, 2, and 3 only — Lowest Stress, But Not Self Aligning
Pads 1, 2, 3, and A — Standard SOT-89 Layout
Pads 1, 2, 3, and B — Low-Stress Version
Pads 1, 2, and 3 only — Lowest Stress, But Not Self Aligning
Dwg. MA-012-3 in
Dwg. MA-012-3 mm
NOTE: Exact body and lead configuration at vendor’s option within limits shown.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
3150
PROGRAMMABLE, CHOPPERSTABILIZED, PRECISION,
HALL-EFFECT SWITCH
PACKAGE DESIGNATOR 'UA'
Dimensions in Millimeters
(for reference only)
Dimensions in Inches
(controlling dimensions)
4.17
4.04
0.164
0.159
0.062
0.058
45°
1.57
1.47
45°
3.10
2.97
0.122
0.117
45°
45°
0.085
1
2
3
0.031
2.16
1
2
3
0.79
MAX
MAX
0.640
0.600
16.26
15.24
0.0173
0.0138
0.0189
0.0142
SEE NOTE
0.44
0.35
0.48
0.36
SEE NOTE
1.27
0.050
BSC
BSC
Dwg. MH-014E in
Dwg. MH-014E mm
Surface-Mount Lead Form (Suffix '-TL')
2.41
0.095
±0.13
±0.005
0.002
0.051
MAX
MAX
0.004 0°–8°
MAX
0.10
0.020
MIN
FLAT
MAX
Dwg. MH-015 in
0°–8°
0.51
MIN
FLAT
Dwg. MH-015 mm
NOTES: 1. Tolerances on package height and width represent allowable mold offsets. Dimensions given are measured at the widest point (parting line).
2. Exact body and lead configuration at vendor’s option within limits shown.
3. Height does not include mold gate flash.
4. Recommended minimum PWB hole diameter to clear transition area is 0.035” (0.89 mm).
5. Where no tolerance is specified, dimension is nominal.
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3150
PROGRAMMABLE, CHOPPERSTABILIZED, PRECISION,
HALL-EFFECT SWITCH
The products described herein are manufactured under one or more
of the following U.S. patents: 5,045,920; 5,264,783; 5,442,283;
5,389,889; 5,581,179; 5,517,112; 5,619,137; 5,621,319; 5,650,719;
5,686,894; 5,694,038; 5,729,130; 5,917,320; and other patents
pending.
Allegro MicroSystems, Inc. reserves the right to make, from time to
time, such departures from the detail specifications as may be required
to permit improvements in the performance, reliability, or
manufacturability of its products. Before placing an order, the user is
cautioned to verify that the information being relied upon is current.
Allegro products are not authorized for use as critical components
in life-support appliances, devices, or systems without express written
approval.
The information included herein is believed to be accurate and
reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringements of patents or other rights of
third parties that may result from its use.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
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