A3251EUA-TL [SANKEN]
Analog Circuit, 1 Func, PSSO3, ULTRA MINI, SMT-3;
| 型号： | A3251EUA-TL |
| 厂家： | 
SANKEN ELECTRIC |
| 描述： | Analog Circuit, 1 Func, PSSO3, ULTRA MINI, SMT-3 |
| 文件： | 总12页 (文件大小：155K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
3250
PROGRAMMABLE, CHOPPER-
STABILIZED, HALL-EFFECT SWITCH
The A3250x and A3251x programmable switches provide tooth/
valley recognition in large gear-tooth sensing, high-temperature appli-
cations. Each sensor consists of a single element, chopper-stabilized
Hall-effect IC that can be programmed to the desired magnetic switch
point, optimizing sensor 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
A3250x output turns on in the presence of a sufficiently large south-
pole magnetic field while the A3251x turns off with a sufficiently large
south-pole magnetic field.
PTCT
V
CC
The sensing technology used for these sensors is Hall-effect based.
The sensor incorporates a single-element Hall IC that switches in
response to magnetic signals created by a ferrous target. The program-
mability 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 solu-
tions.
1
2
3
A proprietary dynamic offset cancelation technique, with an
internal high-frequency clock, minimizes 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.
Dwg. PH-003-2
PRELIMINARY INFORMATION
(subject to change without notice)
March 20, 2000
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC ........................ 26.5 V*
Reverse Supply Voltage, VRCC ............ -18 V
Output OFF Voltage, VOUT ..................... VCC
Output Current, IOUT ..... Internally Limited
Over-Voltage Supply Current, ICC ... 100 mA
Magnetic Flux Density, B ............ Unlimited
Operating Temperature Range, TA
Suffix ‘E–’.................... -40°C to +85°C
Suffix ‘L–’.................. -40°C to +150°C
Storage Temperature Range,
These sensor systems are ideal for use in gathering speed, position,
and timing information using gear-tooth-based configurations. They are
particularly suited to those applications that require accurate duty cycle
control or accurate edge detection. The lower vibration sensitivity also
Continued next page
TS ................................ -65°C to +170°C
*Fault conditions that produce supply voltage
transients will be clamped by an internal Zener
diode. These conditions can be tolerated but
should be avoided.
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., A3250LLT .
3250
PROGRAMMABLE, CHOPPER-
STABILIZED, PRECISION,
HALL-EFFECT SWITCH
FUNCTIONAL BLOCK DIAGRAM
1
SUPPLY
REG.
PROGRAM
LOGIC
OFFSET
ADJUST
POWER-UP
CONTROL
OUTPUT
X
3
CURRENT
LIMIT
<1Ω
GROUND
2
Dwg. FH-020-3
makes these devices extremely useful for transmission
speed sensing.
FEATURES AND BENEFITS
■ Chopper Stabilized for
The first character of the part number suffix deter-
mines the device operating temperature range. Suffix
‘E–’ is for the automotive and industrial temperature
range of -40°C to +85°C. Suffix ‘L–’ is for the auto-
motive and military temperature range of -40°C to
+150°C. 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.
Extremely Low Switch-Point Drift and
Immunity to Mechanical Stress
■ Externally Programmed Switch Point
■ On-Chip Supply-Transient Protection
■ Output Short-Circuit Protection
■ Reverse Battery Protection
■ 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.
2
3250
PROGRAMMABLE, CHOPPER-
STABILIZED, PRECISION,
HALL-EFFECT SWITCH
ELECTRICAL CHARACTERISTICS over operating voltage and temperature range (unless
otherwise noted).
Limits
Characteristic
Supply Voltage
Power-On State
Symbol
VCC
Test Conditions
Min.
Typ. Max.
26.5
Units
Operating
4.25
—
V
POS
After programming, VCC = 0 ■ 5 V:
A3250x, B < BOP
HIGH HIGH HIGH
LOW LOW LOW
—
—
A3251x, B < BRP
Low Output Voltage
Output Current Limit
Output Leakage Current
Supply Current
VOUT(SAT)
IOUTM
IOFF
Output on, IOUT = 20 mA
—
175
m
400
A
mV
OutpVut 1o2n, =VOUT
65
80
95
Output off, VOUT = 24 V
—
—
—
—
—
—
—
—
27
—
—
10
7.0
8.0
-5.0
50
—
µA
mA
mA
mA
µs
ICC
Before programming, output off
Before programming, output on
VRCC = -30 V
3.0
4.0
—
Reverse Supply Current
Power-On Delay
Output Rise Time
Output Fall Time
Clock Frequency
Zener Voltage
IRCC
ton
tr
VCC > 5 V
20
RL = 820 Ω, CL = 20 pF
RL = 820 Ω, CL = 20 pF
200
100
340
32
ns
tf
—
ns
fC
—
kHz
V
VZ
zz
IZT = 100 µA, TA = 25°C
IZT = 10 mA, TA = 25°C
37
—
Zener Impedance
50
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 range.
Limits
Characteristic
Symbol
Test Conditions
Min.
500
20
Typ. Max.
Units
G
A3250x Operate Point
(output turns on), BOP
BxP
Programmable offset range
Initial (before programming)
Resolution
670
—
850
—
G
A3251x Release Point
(output turns off), BRP
—
10
—
—
G
∆BxP
After programming, BxP ≤ 500 G
-35
5.0
+35
35
G
Hysteresis
Bhys
After programming, |BOP — B |
—
G
RP
NOTE: Typical data is at VCC = 5 V and TA = +25°C and is for design information only.
www.allegromicro.com
3
3250
PROGRAMMABLE, CHOPPER-
STABILIZED, PRECISION,
HALL-EFFECT SWITCH
TYPICAL ELECTRICAL CHARACTERISTICS
5.0
4.0
3.0
10
8.0
6.0
4.0
T
= +25°C
A
V
= 5 V
B > B
CC
OP
B > B
OP
B < B
RP
B < B
RP
2.0
1.0
2.0
0
100
-50
-25
0
25
50
75
125
150
0
5
10
15
20
25
AMBIENT TEMPERATURE IN °C
SUPPLY VOLTAGE IN VOLTS
Dwg. GH-053-2
Dwg. GH-041-2
300
I
= 20 mA
OUT
V
= 4.5–24 V
CC
200
100
0
-50
150
100
125
-25
0
25
50
75
AMBIENT TEMPERATURE IN °C
Dwg. GH-040-4
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
4
3250
PROGRAMMABLE, CHOPPER-
STABILIZED, 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 repeatabil-
ity.
REG
X
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 chopper-
stabilizing 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.
Dwg. EH-012
B
+V
—
HALL
VOLTAGE
Operation. The output of the A3250x switches low (turns on)
when a magnetic field (south pole) perpendicular to the Hall
sensor exceeds the operate point threshold (BOP). After turn-on,
the output is capable of sinking 20 mA and the output voltage is
+
Dwg. AH-011-2
VOUT(SAT). The A3250x operate point is programmable (see
next section). When the magnetic field is reduced below the
release point (BRP), the device output goes high (turns off).
A3250x OUTPUT CHARACTERISTIC
+V
V
CC
B
B
OP
RP
V
OUT(SAT)
0
0
+B
FLUX DENSITY
Dwg. GH-007-2
www.allegromicro.com
5
3250
PROGRAMMABLE, CHOPPER-
STABILIZED, PRECISION,
HALL-EFFECT SWITCH
FUNCTIONAL DESCRIPTION (cont’d)
The output of the A3251x switches high (turns off) when a
magnetic field (south pole) perpendicular to the Hall sensor
exceeds the release point threshold (BRP). The A3251x release
point is programmable (see next section). When the magnetic
field is reduced below the operate point (BOP), the device output
goes low (turns on). After turn-on, the output is capable of
Applications. It is strongly recommended that an external
bypass capacitor be connected (in close proximity to the Hall
sensor) between the supply and ground of the device to reduce
both external noise and noise generated by the chopper-stabiliza-
tion technique.
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 sensors is also available in the Allegro Electronic
Data Book AMS-702 or Application Note 27701, or
sinking 20 mA and the output voltage is VOUT(SAT)
.
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.
www.allegromicro.com
A3251x OUTPUT CHARACTERISTIC
+V
SUPPLY
V
CC
OUTPUT
0.1 µF
B
B
RP
OP
X
SUPPLY
Dwg. EH-013
V
OUT(SAT)
0
0
+B
FLUX DENSITY
Dwg. GH-007-5
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
6
3250
PROGRAMMABLE, CHOPPER-
STABILIZED, PRECISION,
HALL-EFFECT SWITCH
PROGRAMMING PROTOCOL
The A3250x operate point and A3251x release point are
programmed by serially addressing the device through the
supply terminal (pin1). After the correct operate/release
point is determined, the device programming bits are
selected and then a “lock” set to prevent any further
(accidental) programming.
VPP
PROGRAM ENABLE
(AT LEAST 7 PULSES)
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 interrup-
tions, is designed to prevent the device from being pro-
grammed accidentally (for example, as a result of noise on
the supply line).
V
PH
V
PL
t
d(1)
t
d(1)
td(0)
0
Dwg. WH-013
Figure 1 — Program enable
PROGRAMMING PROTOCOL over operating temperature range.
Limits
Characteristic
Symbol
VPL
VPH
VPP
IPP
Description
Min.
4.5
9.0
20
Typ. Max.
Units
V
Programming Voltage
Minimum voltage during programming
5.0
10
5.5
11
25
—
—
—
—
—
—
V
23
V
Programming Current
Pulse Width
Max. supply current during programming
OFF time between bits
—
250
—
mA
µs
µs
µs
µs
µs
td(0)
td(1)
tdP
20
Enable, address, program, or lock bit ON time
Program pulse ON time
20
—
100
11
300
—
Pulse Rise Time
Pulse Fall Time
tr
VPL to VPH or VPP
tf
VPH or VPP to VPL
5.0
—
NOTE: Typical data is at TA = +25°C and is for design information only.
www.allegromicro.com
7
3250
PROGRAMMABLE, CHOPPER-
STABILIZED, PRECISION,
HALL-EFFECT SWITCH
Address Determination. The operate point is adjust-
able 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.
V
PH
V
PL
td(1)
t
d(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
Lock Programming. After the desired set point is
programmed, the program lock is then activated (figure 4)
to prevent further programming of the device.
VPP
PROGRAM ENABLE
BIT 3 PROGRAM
(000100)
PROGRAM ENABLE
ADDRESS 4
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.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
8
3250
PROGRAMMABLE, CHOPPER-
STABILIZED, PRECISION,
HALL-EFFECT SWITCH
CRITERIA FOR DEVICE QUALIFICATION
All Allegro sensors 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
50 hrs
Samples
Comments
Biased Humidity (HAST) TA = 130°C, RH = 85%
77
77
VCC = VOUT = 5 V
High-Temperature
Operating Life (HTOL)
JESD22-A108,
TA = 150°C, TJ = 165°C
408 hrs
VCC = 24 V,
VOUT = 20 V
Accelerated HTOL
JESD22-A108,
TA = 175°C, TJ = 190°C
504 hrs
96 hrs
77
77
77
77
6
VCC = 24 V,
VOUT = 20 V
Autoclave, Unbiased
JESD22-A102, Condition C,
TA = 121°C, 15 psig
High-Temperature
(Bake) Storage Life
MIL-STD-883, Method 1008,
TA = 170°C
1000 hrs
500 cycles
Temperature Cycle
MIL-STD-883, Method 1010,
-65°C to +150°C
Latch-Up
Pre/Post
Reading
Electro-Thermally
Induced Gate Leakage
Pre/Post
Reading
6
ESD,
Human Body Model
CDF-AEC-Q100-002
Per Specification
Pre/Post
Reading
x per
test
Test to failure,
All leads > TBD
Electrical Distributions
30
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9
3250
PROGRAMMABLE, CHOPPER-
STABILIZED, PRECISION,
HALL-EFFECT SWITCH
SENSOR LOCATIONS
(±0.005 [0.13 mm] die placement)
Package Designator “LT”
ACTIVE AREA DEPTH
0.0305"
0.088"
0.775 mm
2.24 mm
NOM
0.045"
1.14 mm
A
1
2
3
Dwg. MH-008-8A
Package Designators “UA” and "UA-TL"
ACTIVE AREA DEPTH
0.0195"
0.080"
0.50 mm
2.04 mm
NOM
0.056"
1.44 mm
A
BRANDED
SURFACE
1
2
3
Dwg. MH-011-9B
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.
Although sensor location is accurate to three sigma for a
particular design, product improvements may result in small
changes to sensor location.
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 responsibil-
ity for its use; nor for any infringements of patents or other rights of
third parties that may result from its use.
Allegro
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
10
3250
PROGRAMMABLE, CHOPPER-
STABILIZED, PRECISION,
HALL-EFFECT SWITCH
PACKAGE DESIGNATOR 'LT'
(SOT-89/TO-243AA)
Dimensions in Inches
(for reference only)
Dimensions in Millimeters
(controlling dimensions)
0.181
0.063
0.055
4.60
4.40
1.83
1.62
1.60
1.40
0.173
0.0173
0.0138
0.44
0.35
0.072
0.064
0.102
0.090
0.090
0.084
2.60
2.29
2.29
2.13
0.167
0.155
4.25
3.94
2
3
2
3
1
1
0.0189
0.0142
0.0221
0.0173
0.48
0.36
0.047
1.20
0.89
0.035
0.56
0.44
1.50
0.059
BSC
BSC
3.00
0.118
BSC
BSC
Dwg. MA-009-3A mm
Dwg. MA-009-3A in
0.098
0.079
2.5
2.0
B
B
0.8
0.031
2.6
0.102
0.181
A
A
2
4.6
1.2
0.8
0.047
3
1
2
3
1
0.7
TYP
0.028
TYP
0.031
TYP
TYP
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
ds 1, 2, 3, and A — Standard SOT-89 Layout
ds 1, 2, 3, and B — Low-Stress Version
ds 1, 2, and 3 only — Lowest Stress, But Not Self Aligning
Dwg. MA-012-3 mm
Dwg. MA-012-3 in
NOTE: Exact body and lead configuration at vendor’s option within limits shown.
www.allegromicro.com
11
3250
PROGRAMMABLE, CHOPPER-
STABILIZED, PRECISION,
HALL-EFFECT SWITCH
PACKAGE DESIGNATOR 'UA'
Dimensions in Millimeters
Dimensions in Inches
(controlling dimensions)
(for reference only)
0.164
0.159
4.17
4.04
0.062
0.058
1.57
1.47
45°
45°
0.122
0.117
3.10
2.97
45°
45°
0.031
0.79
0.085
2.16
1
2
3
1
2
3
MAX
MAX
0.640
0.600
0.0173
0.0138
16.26
15.24
0.44
0.35
0.48
0.36
0.0189
0.0142
SEE NOTE
SEE NOTE
0.050
BSC
1.27
BSC
Dwg. MH-014E in
Dwg. MH-014E mm
Surface-Mount Lead Form (Suffix '-TL')
0.095
±0.005
2.41
±0.13
0.002
MAX
0.051
MAX
0°–8°
0°–8°
0.51
MAX
0.004
MAX
0.10
0.020
MIN
FLAT
MIN
FLAT
Dwg. MH-015 in
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.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
12
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