Easily manufacturable with magnet pole independence
DESCRIPTION
The A3211 and A3212 integrated circuits are ultrasensitive, pole
independent Hall-effect switches with latched digital output.
These devices are especially suited for operation in battery-
operated, hand-held equipment such as cellular and cordless
telephones, pagers, and palmtop computers. A 2.5 to 3.5 V
operation and a unique clocking scheme reduce the average
operating power requirements to less than 15
μW
with a
2.75 V supply.
Unlike other Hall-effect switches, either a north or south pole
of sufficient strength will turn the output on in the A3212,
and in the absence of a magnetic field, the output is off. The
A3211 provides an inverted output. The polarity independence
and minimal power requirements allow these devices to easily
replace reed switches for superior reliability and ease of
manufacturing, while eliminating the requirement for signal
conditioning.
Improved stability is made possible through chopper
stabilization (dynamic offset cancellation), which reduces the
residual offset voltage normally caused by device overmolding,
temperature dependencies, and thermal stress.
This device includes on a single silicon chip a Hall-voltage
generator, small-signal amplifier, chopper stabilization, a
latch, and a MOSFET output. Advanced CMOS processing
is used to take advantage of low-voltage and low-power
SIP (UA)
•
•
•
•
PACKAGES:
DFN (EL)
DFN (EH)
SOT23W (LH)
Not to scale
Continued on next page....
SUPPLY
SWITCH
TIMING
LOGIC
DYNAMIC
OFFSET CANCELLATION
OUTPUT
SAMPLE
& HOLD
LATCH
X
GROUND
Dwg. FH-020-5
Functional Block Diagram
3211-DS, Rev. 24
February 27, 2017
A3211
and
A3212
DESCRIPTION (continued)
Micropower, Ultrasensitive
Hall-Effect Switches
requirements, component matching, very low input-offset errors,
and small component geometries.
Four package styles provide magnetically optimized solutions for
most applications. Miniature low-profile surface-mount package
types
EH
and
EL
(0.75 and 0.50 mm nominal height) are leadless,
LH
is a 3-pin low-profile SMD, and
UA
is a three-pin SIP for through-
hole mounting. Packages are lead (Pb) free (suffix,
–T)
with 100%
matte-tin-plated leadframes.
SPECIFICATIONS
SELECTION GUIDE
Part Number
A3211EEHLT–T
[2][3][4]
A3211EELLT–T
[2][4][5]
A3211ELHLT–T
[4]
A3211ELHLX–T
[4]
A3212EEHLT–T
[2][3]
A3212EELLT–T
[2][5]
A3212ELHLT–T
A3212ELHLX–T
A3212EUA–T
A3212LLHLT–T
A3212LLHLX–T
A3212LUA–T
1
Contact Allegro
2
Allegro
Packing
[1]
3000 pieces per reel
3000 pieces per reel
3000 pieces per reel
10000 pieces per 13-in. reel
3000 pieces per reel
3000 pieces per reel
3000 pieces per reel
10000 pieces per 13-in. reel
500 pieces per bulk bag
3000 pieces per reel
10000 pieces per 13-in. reel
500 pieces per bulk bag
Package
2 mm × 3 mm, 0.75 mm nominal height DFN
2 mm × 2 mm, 0.50 mm nominal height DFN
3-pin surface mount SOT23W
3-pin surface mount SOT23W
2 mm × 3 mm, 0.75 mm nominal height DFN
2 mm × 2 mm, 0.50 mm nominal height DFN
3-pin surface mount SOT23W
3-pin surface mount SOT23W
SIP-3 through hole
3-pin surface mount SOT23W
3-pin surface mount SOT23W
SIP-3 through hole
Ambient Temperature
T
A
(°C)
State in
Magnetic Field
–40 to 85
Off
–40 to 85
On
–40 to 150
for additional packaging and handling options.
products sold in DFN package types are not intended for automotive applications.
3
Variant is no longer in production. The device should not be purchased for new design applications. Samples are no longer available.
Date of status change: June 1, 2015 (A3212EEHLT-T), December 1, 2015 (A3211EEHLT-T).
4
For automotive sales, please contact the field applications engineer.
5
Variant is in production but has been determined to be LAST TIME BUY. This classification indicates that the product is obsolete and notice has been given. Sale of this
device is currently restricted to existing customer applications. The device should not be purchased for new design applications because of obsolescence in the near
future. Samples are no longer available. Date of status change: September 1, 2016.
ABSOLUTE MAXIMUM RATINGS
Characteristic
Supply Voltage
Magnetic Flux Density
Output Off Voltage
Output Current
Operating Ambient Temperature
Maximum Junction Temperature
Storage Temperature
Symbol
V
DD
B
V
OUT
I
OUT
T
A
T
J
(max)
T
stg
Range E
Range L
Notes
Rating
5
Unlimited
5
1
–40 to 85
–40 to 150
165
–65 to 170
Units
V
G
V
mA
°C
°C
°C
°C
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
2
A3211
and
A3212
Micropower, Ultrasensitive
Hall-Effect Switches
PINOUT DRAWINGS
Package Suffix ‘EH’ Pinning
(Leadless Chip Carrier)
NO
CONNECTION
Dwg. PH-016-2
Package Suffix ‘EL’ Pinning
(Leadless Chip Carrier)
GROUND
SUPPLY
6
V
DD
3
5
4
X
V
1
OUTPUT
DD
2
NO
CONNECTION
3
GROUND
1
2
GROUND
2
n
Dwg. PH-016-1
Package Suffix ‘LH’ Pinning
(SOT23W)
Package Suffix ‘UA’ Pinning
(SIP)
3
X
V
DD
V
DD
1
2
1
3
GROUND
OUTPUT
SUPPLY
GROUND
Dwg. PH-016-1
Dwg. PH-016
Pinning is shown viewed from branded side.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
OUTPUT
SUPPLY
OUTPUT
SUPPLY
3
A3211
and
A3212
Micropower, Ultrasensitive
Hall-Effect Switches
ELECTRICAL CHARACTERISTICS: Over operating voltage and temperature range (unless otherwise specified)
Characteristic
Supply Voltage Range
Output Leakage Current
Output On Voltage
Awake Time
Period
Duty Cycle
Chopping Frequency
Symbol
V
DD
I
OFF
V
OUT
t
awake
t
period
d.c.
f
C
I
DD(EN)
Supply Current
I
DD(DIS)
I
DD(AVG)
Chip awake (enabled)
Chip asleep (disabled)
V
DD
= 2.75 V
V
DD
= 3.5 V
Operating
V
OUT
= 3.5 V, Output off
I
OUT
= 1 mA, V
DD
= 2.75 V
Test Conditions
Limits
Min.
2.5
–
–
–
–
–
–
–
–
–
–
Typ.*
2.75
<1.0
100
45
45
0.1
340
–
–
5.1
6.7
Max.
3.5
1.0
300
90
90
–
–
2.0
8.0
10
10
Units
V
µA
mV
µs
ms
%
kHz
mA
µA
µA
µA
* Typical data is at T
A
= 25°C and V
DD
= 2.75 V, and is for design information only.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
4
A3211
and
A3212
Micropower, Ultrasensitive
Hall-Effect Switches
A3211 MAGNETIC CHARACTERISTICS:
Over operating voltage range (unless otherwise specified)
Characteristic
Symbol
Test Conditions
Limits
Min.
–
–55
10
–
–
Typ.
37
–40
31
–34
5.9
Max.
55
–
–
–10
–
Units
G
G
G
G
G
Over Temperature Range E: T
A
= –40°C to 85°C
Operate Points
Release Points
Hysteresis
NOTES:
B
OPS
B
OPN
B
RPS
B
RPN
B
HYS
South pole to branded side; B > B
OP
, V
OUT
= High (Output Off)
North pole to branded side; B > B
OP
, V
OUT
= High (Output Off)
South pole to branded side; B < B
RP
, V
OUT
= Low (Output On)
North pole to branded side; B < B
RP
, V
OUT
= Low (Output On)
|B
OPx
- B
RPx
|
1. Negative flux densities are defined as less than zero (algebraic convention), i.e., -50 G is less than +10 G.
2. B
OPx
= operate point (output turns off); B
RPx
= release point (output turns on).
3. Typical Data is at T
A
= +25°C and V
DD
= 2.75 V and is for design information only.
4. 1 gauss (G) is exactly equal to 0.1 millitesla (mT).
A3212 MAGNETIC CHARACTERISTICS:
Over operating voltage range (unless otherwise specified)
Characteristic
Symbol
Test Conditions
Limits
Min.
–
–55
10
–
–
–
–65
10
–
–
Typ.
37
–40
31
–34
5.9
37
–40
31
–34
5.9
Max.
55
–
–
–10
–
65
–
–
–10
–
Units
G
G
G
G
G
G
G
G
G
G
Over Temperature Range E: T
A
= –40°C to 85°C
Operate Points
Release Points
Hysteresis
B
OPS
B
OPN
B
RPS
B
RPN
B
HYS
B
OPS
B
OPN
B
RPS
B
RPN
B
HYS
South pole to branded side; B > B
OP
, V
OUT
= Low (Output On)
North pole to branded side; B > B
OP
, V
OUT
= Low (Output On)
South pole to branded side; B < B
RP
, V
OUT
= High (Output Off)
North pole to branded side; B < B
RP
, V
OUT
= High (Output Off)
|B
OPx
- B
RPx
|
South pole to branded side; B > B
OP
, V
OUT
= Low (Output On)
North pole to branded side; B > B
OP
, V
OUT
= Low (Output On)
South pole to branded side; B < B
RP
, V
OUT
= High (Output Off)
North pole to branded side; B < B
RP
, V
OUT
= High (Output Off)
|B
OPx
- B
RPx
|
Over Temperature Range L: T
A
= –40°C to 150°C
Operate Points
Release Points
Hysteresis
NOTES:
1. Negative flux densities are defined as less than zero (algebraic convention), i.e., -50 G is less than +10 G.
2. B
OPx
= operate point (output turns on); B
RPx
= release point (output turns off).
3. Typical Data is at T
A
= +25°C and V
DD
= 2.75 V and is for design information only.
4. 1 gauss (G) is exactly equal to 0.1 millitesla (mT).
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