A3423 Datasheet

A3423
Dual Channel Hall Effect Direction Detection Sensor IC
This device is in production, however, it has been deemed Pre-End
of Life. The product is approaching end of life. Within a minimum of
6 months, the device will enter its final, Last Time Buy, order phase.
Date of status change: June 3, 2013
Recommended Substitutions:
For existing customer transition, and for new customers or new applications, refer to the A1233.
NOTE: For detailed information on purchasing options, contact your
local Allegro field applications engineer or sales representative.
Allegro MicroSystems, LLC reserves the right to make, from time to time, revisions to the anticipated product life cycle plan
for a product to accommodate changes in production capabilities, alternative product availabilities, or market demand. The
information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, LLC assumes no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use.
A3423
Dual Channel Hall Effect Direction Detection Sensor IC
Features and Benefits
Description
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The A3423 is a dual-channel Hall-effect sensor IC ideal for
use in speed and direction sensing applications incorporating
encoder ring-magnet targets. The A3423 provides various output
signals that indicate speed and direction of target rotation. The
Hall elements are both photolithographically aligned to better
than 1 μm. Maintaining accurate displacement between the two
active Hall elements eliminates the major manufacturing hurdle
encountered in fine-pitch detection applications. The A3423 is
a highly sensitive, temperature-stable magnetic device ideal for
use in harsh automotive and industrial environments.
Precisely aligned dual Hall elements
Tightly matched magnetic switchpoints
Speed and direction outputs
Individual Hall element outputs (L package)
Fast power-on time
Output short circuit protection
Operation from an unregulated power supply
Wide operating temperature range
Wide operating voltage range
Integrated EMC-ESD protection
Packages
8-pin SOIC (suffix L)
4-pin SIP (suffix K)
The Hall elements of the A3423 are spaced 1.63 mm apart,
which provides excellent speed and direction information
for small-geometry targets. Extremely low-drift amplifiers
guarantee symmetry between the switches to maintain signal
quadrature. An on-chip regulator allows the use of this device
over a wide operating voltage range of 3.8 to 24 V.
End-of-line trimming of the Hall element switchpoints provides
tight matching capability. The continuous-time nature of the
Hall elements delivers a fast start-up of the device and low
noise.
The A3423 has integrated protection against transients on
the supply and output pins and short-circuit protection on all
outputs.
Not to scale
The A3423 is available in a 4-pin SIP and a plastic 8-pin
SOIC surface mount package (the SOIC version is currently
in development). Both packages are lead (Pb) free, with 100%
matte tin leadframe plating.
Functional Block Diagram
L package only
VCC
Regulator
Output
Current
Limit
OUTA
Output
Current
Limit
DIR
Output
Current
Limit
SPD
Output
Current
Limit
OUTB
Power-on
Logic
Direction
Logic
E1
Trim
E2
GND
A3423-DS, Rev. 5
L package only
A3423
Dual Channel Hall Effect Direction Detection Sensor IC
Selection Guide
Part Number
Packing1
Package
A3423EK-T
4-pin through hole SIP
Bulk bag, 500 pieces/bag
A3423ELTR-T
8-pin surface mount SOIC2
Tape and reel, 3000 pieces/reel
A3423LK-T
4-pin through hole SIP
Bulk bag, 500 pieces/bag
A3423LLTR-T
8-pin surface mount SOIC2
1Contact Allegro for additional packing options.
2SOIC package currently in development.
Tape and reel, 3000 pieces/reel
TA
(°C)
–40 to 85
–40 to 150
Absolute Maximum Ratings
Characteristic
Symbol
Notes
Units
Supply Voltage
VCC
30
V
Reverse Battery Voltage
VRB
–30
V
VOUT
VCC
V
IOUT(SINK)
30
mA
Output Off Voltage
Output Sink Current
Magnetic Flux Density
–40°C to 150°C
Rating
B
Unlimited
G
Range E
–40 to 85
ºC
Range L
Operating Ambient Temperature
TA
–40 to 150
ºC
Storage Temperature
Tstg
–65 to 165
ºC
TJ(max)
165
ºC
Maximum Junction Temperature
Pin-out Diagrams
Terminal List Table
Number
K
L
VCC
1
8 GND
1
1
Name
Description
VCC
Input power supply; tie to GND with bypass capacitor
Output signal indicating direction of target movement
DIR
2
7 NC
2
2
DIR
OUTA
3
6 NC
–
3
OUTA
Analog output indicating B at E1 Hall element
SPD
4
5 OUTB
3
4
SPD
Output signal indicating speed of target movement
–
5
OUTB
–
6, 7
NC
4
8
GND
L Package
4
GND
DIR
3
SPD
2
VCC
1
Analog output indicating B at E2 Hall element
No connection
Ground connection
K Package
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
2
A3423
Dual Channel Hall Effect Direction Detection Sensor IC
OPERATING CHARACTERISTICS valid at TA = –40°C to 150°C, TJ ≤ TJ (max), through full operating air gap range, unless otherwise noted
Characteristics
Symbol
Test Conditions
Min.
Typ.
Max.
Units
3.8
–
24
V
–
<1
10
μA
–
–
3.7
V
Electrical Characteristics
Supply Voltage
Output Leakage Current
VCC
Operating, TJ ≤ 165°C
IOFF
All outputs VOUT ≤ VCC(max)
Undervoltage Lockout
VCC(UV)
Undervoltage Hysteresis
VCC(hys)
Lockout (VCC(UV)) – Shutdown
–
0.4
–
V
tr
CLOAD = 20 pF, RLOAD = 1 kΩ
–
200
–
ns
tf
CLOAD = 20 pF, RLOAD = 1 kΩ
Output Rise Time
Output Fall Time
Supply Current
ICC
Low Output Voltage
Vsat
Output Current Limit
IOM
Speed Output Delay*
Power-on Time
td
tON
–
300
–
ns
3.4
8.2
14
mA
All outputs; IOUT = 15 mA; B > BOP(A), B > BOP(B)
–
210
500
mV
All outputs
30
–
60
mA
Delay between direction changing and speed
output transition
0.5
2.5
5
μs
B > BOP + 5 G
–
2
5
μs
–
V
Transient Protection Characteristics
Supply Zener Voltage
VZ(sup)
ICC = 17 mA, TA = 25°C
30
–
Output Zener Voltage
VZ(out)
IOUT = 3 mA, TA = 25°C
30
–
–
V
Supply Zener Current
IZ(sup)
Vsupply = 30 V, TA = 25°C
–
–
17
mA
Output Zener Current
IZ(out)
VOUT = 30 V, TA = 25°C
–
–
3
mA
Reverse Battery Current
IRCC
VRCC = –28 V, TA = 25°C
–
–
15
mA
Operate Point (Channel A and Channel B)
BOP
B(A) > BOP(A), B(B) > BOP(B)
–35
15
55
G
Release Point (Channel A and Channel B)
BRP
B(A) < BOP(A), B(B) < BOP(B)
–55
–15
35
G
Bhys
Magnetic Characteristics
Hysteresis (Channel A and Channel B)
BOP – BRP
10
30
60
G
Operate Symmetry
SYMOP(AB)
BOP(A) – BOP(B)
–50
–
50
G
Release Symmetry
SYMRP(AB)
BRP(A) – BRP(B)
–50
–
50
G
* Valid only after the first speed (SPD pin) signal transition. First speed signal transition has no delay.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
3
A3423
Dual Channel Hall Effect Direction Detection Sensor IC
THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information
Characteristic
Symbol
RθJA
Package Thermal Resistance
Test Conditions*
Value Units
Package K, 1-layer PCB with copper limited to solder pads
177
ºC/W
Package L, 1-layer PCB with copper limited to solder pads
140
ºC/W
Package L, 4-layer PCB
80
ºC/W
*Additional thermal information available on Allegro website.
Maximum Allowable VCC (V)
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
VCC(max)
Package K
(RQJA = 177 ºC/W)
1-layer PCB, Package L
(RQJA = 140 ºC/W)
4-layer PCB, Package L
(RQJA = 80 ºC/W)
VCC(min)
20
40
60
80
100
120
140
160
180
Temperature (ºC)
Power Dissipation, PD (mW)
Power Dissipation versus Ambient Temperature
1900
1800
1700
1600
1500
1400
1300
1200
1100
1000
900
800
700
600
500
400
300
200
100
0
4
(R -lay
QJ
A
er
= PC
80 B
ºC , Pa
/W ck
) ag
1-l
(R ayer
PC
QJ
A =
14 B, P
0 º ac
C/ kag
W)
eL
Pac
(R kage K
QJA =
177
20
40
60
ºC/
e
L
W)
80
100
120
Temperature (°C)
140
160
180
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
4
A3423
Dual Channel Hall Effect Direction Detection Sensor IC
Performance Characteristics
Supply Current at TA = 25°C
Supply Current versus Ambient Temperature
13
10
3 outputs on, Vcc=8V
3 outputs off, Vcc=8V
3 outputs on, Vcc=12V
8
3 outputs off, Vcc=12V
7
Supply Current (mA)
Supply Current (mA)
12
9
6
11
3 outputs on
3 outputs off
10
9
8
7
6
5
5
-50
-25
0
25
50
75
100
125
150
2
4
6
8
TA (°C)
14
16
18
20
22
24
Magnetic Operate Point versus Ambient Temperature
400
55
350
45
300
35
25
250
200
Iout = 20mA
Iout = 15mA
150
BOP (G)
Vsat (mV)
12
VCC (V)
Saturation Voltage versus Ambient Temperature
100
Vcc = 3.8V
Vcc = 8V
Vcc = 12V
Vcc = 18V
Vcc = 24V
15
5
-5
-15
50
-25
0
-35
-50
0
50
100
150
-50
0
TA (°C)
50
100
150
TA (°C)
Magnetic Release Point versus Ambient Temperature
Hysteresis versus Ambient Temperature
35
60
25
55
50
15
Vcc = 3.8V
Vcc = 8V
Vcc = 12V
Vcc = 18V
Vcc = 24V
-5
-15
-25
-35
45
Hysteresis (G)
5
BRP (G)
10
Vcc = 3.8V
Vcc = 8V
Vcc = 12V
Vcc = 18V
Vcc = 24V
40
35
30
25
20
-45
15
-55
10
-50
0
50
TA (°C)
100
150
-50
0
50
100
150
TA (°C)
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
5
A3423
Dual Channel Hall Effect Direction Detection Sensor IC
Functional Description
The integrated circuit contains an internal voltage regulator that
powers the Hall elements and both the analog and digital circuitry. This regulator allows operation over a wide supply voltage
range and provides some immunity to supply noise. The device
also contains logic circuitry that decodes the direction of rotation
of the ring magnet.
The response of the device to the magnetic field produced by a
rotating ring magnet is shown in the Performance Characteristics
section. Note the phase shift between the two integrated Hall elements.
Quadrature/Direction Detection Internal logic circuitry provides
outputs representing the speed and direction of the magnetic
field across the face of the package. For the direction signal to be
appropriately updated, a quadrature relationship must be maintained between the target magnetic pole width, the pitch between
the two Hall elements (E1 and E2) in the device, and, to a lesser
extent, the magnetic switchpoints.
direction (DIR pin), E1 element output (OUTA pin), E2 element
output (OUTB pin), and target speed (SPD pin).
For optimal design, the device should be actuated by a ring
magnet that presents to the front of the device a field with a pole
width two times the Hall element-to-element spacing. This will
produce a sinusoidal magnetic field whose period (denoted as Τ)
is then four times the element-to-element spacing. A quadrature
relationship can also be maintained for a ring magnet with fields
having a period that satisfies the relationship:
nΤ/4 = 1.63 mm ,
where n is any odd integer. Therefore, ring magnets with polepair spacing equal to 6.52 mm (n = 1), 2.17 mm (n = 3), 1.3 mm
(n = 5), and so forth, are permitted.
Outputs The device provides up to four saturated outputs: target
DIR provides the direction output of the device and is defined
as off (high) for targets moving in the direction from E1 to E2
and on (low) for the direction E2 to E1. SPD provides an XORed
output of the two Hall elements (see figure 1). Because of internal delays, DIR is always updated before SPD and is updated at
every transition of OUTA and OUTB (internal) allowing the use
of up-down counters without the loss of pulses.
Power-on State At power on, the logic circuitry is reset to pro-
vide an off (high) state for all the outputs. If any of the channels
is subjected to a field greater than BOP, the internal logic will set
accordingly, and the outputs will switch to the expected state.
Power-on Time This characteristic, tON, is the elapsed time from
when the supply voltage reaches the device supply minimum
until the device output becomes valid (see figure 2).
Target changes direction of rotation
+B
0
–B
+B
0
–B
OUTA
OUTB
SPD
(OUTA XOR
OUTB)
DIR
td
Figure 1
Figure 2
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
6
A3423
Dual Channel Hall Effect Direction Detection Sensor IC
Application Information
Operation with Fine-Pitch Ring Magnets. For targets with a cir-
cular pitch of less than 4 mm, a performance improvement can be
observed by rotating the front face of the device (see below). This
rotation decreases the effective Hall element-to-element spacing,
provided that the Hall elements are not rotated beyond the width
of the target.
Applications. It is strongly recommended that an external
0.01 μF bypass capacitor be connected (in close proximity to the
device) between the supply and ground of the device to
Normal Coplanar Alignment
reduce both external noise and noise generated by the internal
logic.
The simplest form of magnet that will operate these devices is a
ring magnet. Other methods of operation, such as linear magnets,
are possible. Extensive applications information on magnets and
Hall-effect sensor ICs is also available in the “Hall-Effect IC
Applications Guide” which can be found in the latest issue of
Application Note 27701, at www.allegromicro.com/techpub2/an/
an27701.pdf.
Rotated Alignment
D cos A
D
Target Profile of Rotation
S
N
S
E1
E1
E2
E2
A
Target Circular Pitch, P
Target Face Width, F
F < D sin A
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
7
A3423
Dual Channel Hall Effect Direction Detection Sensor IC
Package K, 4-Pin SIP
+0.08
5.21 –0.05
45°
B
E
1.63
E
1.55 ±0.05
1.79
D
NNNN
1.32 E
+0.08
3.43 –0.05
E1
E2
2.16
MAX
Mold Ejector
Pin Indent
Branded
Face
2
3
D Standard Branding Reference View
0.84 REF
N = Device part number
Y = Last two digits of year of manufacture
W = Week of manufacture
For Reference Only; not for tooling use (reference DWG-9010)
Dimensions in millimeters
Dimensions exclusive of mold flash, gate burrs, and dambar protrusions
Exact case and lead configuration at supplier discretion within limits shown
4
14.73 ±0.51
+0.06
0.38 –0.03
+0.07
0.41 –0.05
1
45°
A
1
YYWW
A
Dambar removal protrusion (8X)
B
Gate and tie bar burr area
C
Branding scale and appearance at supplier discretion
D Active Area Depth, .0.42 mm
E Hall elements (E1 and E2); not to scale
1.27 NOM
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
8
A3423
Dual Channel Hall Effect Direction Detection Sensor IC
Package L, 8-Pin SOIC
4.90 ±0.10
1.63 E
1.63 E
8
D
8°
0°
0.65
1.27
8
1.75
0.25
0.17
1.95 E
E1
3.90 ±0.10
A
1
6.00 ±0.20
5.60
1.04 REF
E2
2
0.25 BSC
SEATING
PLANE
0.10 C
1.27 BSC
C
2
PCB Layout Reference View
SEATING PLANE
GAUGE PLANE
Branded Face
8X
0.51
0.31
1
1.27
0.40
E 1.09
C
NNNNNNN
YYWW
LLLLL
1.75 MAX
0.25
0.10
For Reference Only; not for tooling use (reference MS-012AA)
Dimensions in millimeters
Dimensions exclusive of mold flash, gate burrs, and dambar protrusions
Exact case and lead configuration at supplier discretion within limits shown
A Terminal #1 mark area
B Branding scale and appearance at supplier discretion
C
Reference land pattern layout (reference IPC7351
SOIC127P600X175-8M); all pads a minimum of 0.20 mm from all
adjacent pads; adjust as necessary to meet application process
requirements and PCB layout tolerances
D
Active Area Depth 0.40 NOM
E
Hall elements (E1 and E2); not to scale
1
B Standard Branding Reference View
N = Device part number
= Supplier emblem
Y = Last two digits of year of manufacture
W = Week of manufacture
L = Lot number
Copyright ©2007-2013, Allegro MicroSystems, LLC
Allegro MicroSystems, LLC 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’s products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the
failure of that life support device or system, or to affect the safety or effectiveness of that device or system.
The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, LLC assumes no responsibility for its
use; nor for any infringement of patents or other rights of third parties which may result from its use.
For the latest version of this document, visit our website:
www.allegromicro.com
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
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