ATS627 Datasheet

ATS627LSG
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
Description
Features and Benefits
• Highly accurate in presence of:
▫ Anomalous target geometry (tooth-tooth variation)
▫ Signature teeth or valleys
▫ Target runout
• Highly repeatable output edges (low jitter)
• True zero-speed operation
• Undervoltage lockout
• Air gap independent switchpoints
• Defined power-on state
• High operating temperature
• Single-chip sensing IC for high reliability
• Enhanced quality through Scan Path and IDDQ
measurement
• Enhanced EMC performance
Package: 4-pin SIP (suffix SG)
Not to scale
The ATS627 is a true zero-speed gear tooth sensor IC consisting
of an optimized Hall IC and rare earth pellet configuration in
a single overmolded package. The integrated circuit provides
a manufacturer-friendly solution for digital gear tooth sensing
applications. This small package can be easily assembled and
used in conjunction with gears of various shapes and sizes.
The dual-element Hall IC switches in response to differential
magnetic signals created by a ferrous target. Digital processing
of the analog signal provides zero-speed performance
independent of air gap as well as dynamic adaptation of
device performance to the typical operating conditions found
in automotive applications.
High-resolution peak detecting DACs are used to set the
adaptive switching thresholds of the device. Bounded tracking
and switchpoint hysteresis reduce the negative effects of any
anomalies in the magnetic signal associated with the targets
used in many automotive applications. This sensor IC system
is optimized for engine crank applications that utilize targets
that possess signature regions.
This device is available in a lead (Pb) free 4-pin SIP package
(SG) with a 100% matte tin plated leadframe.
Functional Block Diagram
VCC
Multiplexed
Test Signals
Analog
Regulators
–
PDAC
Hall
Amp
Offset
Adjust
Filter
VOUT
+
Digital
Regulator
AGC
NDAC
Reference
Generator
and
Lockout
Current
Limit
Synchronous
Digital Controller
GND
ATS627LSG-DS, Rev. 1
TEST
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Selection Guide
Part Number
Packing*
ATS627LSGTN-T
800 pieces per 13-in. reel
*Contact Allegro™ for additional packing options
Absolute Maximum Ratings
Characteristic
Symbol
Supply Voltage
VCC
Output Off Voltage
Notes
Refer to Power Derating Section
VOUTOFF
Rating
Unit
26.5
V
26.5
V
Reverse Supply Voltage
VRCC
–18
V
Reverse Output Voltage
VROUT
–0.5
V
Output Current
IOUTSINK
25
mA
–40 to 150
ºC
TJ(max)
165
ºC
Tstg
–65 to 170
ºC
Operating Ambient Temperature
TA
Maximum Junction Temperature
Storage Temperature
L temperature range
Pin-out Diagram
Terminal List Table
1
2
3
4
Number
Name
Function
1
VCC
2
VOUT
Open drain output
3
TEST
Test pin
4
GND
Ground
Supply voltage
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
2
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
OPERATING CHARACTERISTICS Valid through full operating supply voltage and ambient temperature ranges, using
Reference Target 60+2; unless otherwise specified
Characteristics
Symbol
Min.
Typ.1
Max.
Unit
4.0
–
24
V
VCC = 0 → 5 V or 5 → 0 V
–
3.6
3.95
V
VCC = VRCC(max)
–
–
–10
mA
Test Conditions
Electrical Characteristics
Supply Voltage2
Undervoltage Lockout
Reverse Supply Current3
Supply Zener Clamp Voltage
Supply Current
Test Pin Zener Clamp Voltage4
VCC
VCC(UV)
IRCC
VZsupply
Operating, TJ < TJ(max)
28
–
–
V
ICC
ICC = ICC(max) + 3 mA, TA = 25ºC
–
7
12
mA
VZTEST
–
6
–
V
VOUT , IC connected as in figure 9
–
High
–
V
VOUT = On (VOUT = low), IOUT = 20 mA
0
–
450
mV
Power-On Characteristics
Power-On State
POS
Output Stage Characteristics
Low Output Voltage
VOUT(SAT)
Output Zener Clamp Voltage
VZOUTPUT
IOUT = 3 mA, TA = 25°C
28
–
–
V
Output Leakage Current
IOUT(OFF)
VOUT = Off (VOUT = high)
–
–
10
μA
Output Current Limit
IOUT(LIM)
VOUT = On (VOUT = low), TJ < TJ(max)
25
45
70
mA
–
10
–
μs
–
0.6
2
μs
–60
–
60
G
–
115
–
mV
Output Rise Time
tr(OUT)
VPU = 12 V, RPU = 1.0 kΩ, CLOAD = 4.7 nF ,
see figure 1
Output Fall Time
tf(OUT)
VPU = 12 V, RPU = 1.0 kΩ, CLOAD = 4.7 nF,
see figure 1
DAC Characteristics
Allowable User-Induced Offset5
BDIFFEXT
Other Operating Characteristics, with Continuous Update method, bounded for increasing and decreasing AG
Running Mode Lockout Enable
LOE
Running Mode Lockout Release
LOR
–
220
–
mV
–
60
–
%
–
%
Operate Point
BOP
% of peak-to-peak VPROC , referenced from
PDAC to NDAC, VOUT high → low
Release Point
BRP
% of peak-to-peak VPROC , referenced from
PDAC to NDAC, VOUT low → high
–
40
f-3dB
Cutoff frequency for low pass filter
–
20
–
kHz
0
–
12 000
rpm
Peak-to-peak differential signal
30
–
1200
G
Compliant to accuracy specifications, measured
from package branded face to target tooth
0.5
–
2.5
mm
No missed edges, measured from package
branded face to target tooth
0.5
–
3.0
mm
–
–
±0.4
deg.
Bandwidth
Operational Speed
SROT
Performance Characteristics
Operational Magnetic Range
Air Gap
Relative Timing Accuracy, Sequential
Mechanical Rising Edges
BIN
AG
ERRRR
0.5 mm ≤ AG ≤ 2.5 mm; constant target speed,
Running mode; relative to measurement taken
at AG = 1.5 mm
Continued on the next page…
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
3
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
OPERATING CHARACTERISTICS (continued) Valid through full operating supply voltage and ambient temperature ranges, using
Reference Target 60+2; unless otherwise specified
Characteristics
Symbol
Test Conditions
Min.
Typ.1
Max.
Unit
Performance Characteristics (continued)
Relative Timing Accuracy, Sequential
Mechanical Falling Edges
ERRFF
0.5 mm ≤ AG ≤ 2.5 mm; constant target speed,
Running mode; relative to measurement taken
at AG = 1.5 mm
–
–
±0.4
deg.
Relative Timing Accuracy, Signature
Mechanical Rising Edge
ERRSIGR
0.5 mm ≤ AG ≤ 2.5 mm; constant target speed,
Running mode; relative to measurement taken
at AG = 1.5 mm
–
–
±0.4
deg.
Relative Timing Accuracy, Signature
Mechanical Falling Edge
ERRSIGF
0.5 mm ≤ AG ≤ 2.5 mm; constant target speed,
Running mode; relative to measurement taken
at AG = 1.5 mm
–
–
±1.5
deg.
0.5 mm ≤ AG ≤ 2.5 mm
–
–
0.08
deg.
See figure 1
–
20
–
μs
Edge Accuracy – First and Second
Output Edges
See figure 2
–TTARGET
–
TTARGET
deg.
Edge Accuracy – Third through Sixth
Output Edges
See figure 2
–0.5 x
TTARGET
–
+0.5 x
TTARGET
deg.
Output edge count (see figure 2),
BSIG / BSEQ = 1, or no signature tooth encountered
–
–
6
–
Output edge count (see figure 2), signature
region encountered during calibration, and
BSIG / BSEQ ≠ 1
–
9
–
–
BSEQ(min) /
Total variation over 60 cycles (see figure 3)
BSEQ(max)
0.5
–
–
–
BSEQ(n+1) /
Single cycle-to-cycle variation (see figure 3)
BSEQ(n)
0.6
–
–
–
0.8
–
1.6
–
Relative Repeatability, Sequential
Rising and Falling Edges6
Output Propagation Delay
Initial Edge
TΘE
td(OUT)
Accuracy7
Full Edge Accuracy
Input Magnetic Characteristics
Allowable Differential Sequential
Signal Variation8
Allowable Signature Amplitude Ratio
BSIG /
BSEQ
One instance per target revolution (see figure 3)
1Typical
values are at TA = 25°C and VCC = 12 V.
voltage must be adjusted for power dissipation and junction temperature; see Power Derating section.
3Negative current is defined as current coming out of (sourced from) the specified device terminal.
4Sustained voltages beyond the clamp voltage may cause permanent damage to the IC.
5 1 G (gauss) = 0.1 mT (millitesla).
6The repeatability specification is based on statistical evaluation of a sample population, evaluated at 1000 Hz.
7Power-on frequencies ≤ 200 Hz. Higher power-on frequencies may result in a delay of full output accuracy or undetected target edges.
8Excludes effects caused by signature region.
2Maximum
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
4
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Processed Input
Signal, VPROC
VPROC(high)
VPROC(BOP)
td(OUT)
td(OUT)
VPROC(BRP)
VPROC(low)
tr(OUT) Time
VOUT(high)
90% VOUT
Output Signal, VOUT
tf(OUT)
10% VOUT
VOUT(low)
Time
Figure 1. Definition of Output Delay Time, td(OUT) , Output Fall Time, tf(OUT) , and Output Rise Time, tr(OUT) .
Target
Valley
Tooth
TTARGET
TVPROC
VPROC
VPROC = the processed analog signal of the sinusoidal magnetic input (per channel)
TTARGET = period between successive sensed target mechanical edges of the same
orientation (either both rising or both falling)
Figure 2. Definition of TTARGET
Signature
Region
Sequential Regions
Sequential Regions
BSEQ(n)
BSEQ(n+1)
BSIG
BSEQ(max)
BSEQ(min)
Figure 3. Differential signature amplification and sequential signal variation
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
5
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Characteristic Performance
Supply Current (On) versus Temperature
12
12
10
10
Supply Current, ICC (mA)
Supply Current, ICC (mA)
Supply Current (On) versus Supply Voltage
8
6
TA (°C)
-40
4
25
85
2
0
150
0
5
10
15
20
25
8
6
VCC (V)
4
12
4
18
2
24
0
-50
30
-25
0
Supply Voltage, VCC (V)
Supply Current (Off) versus Supply Voltage
75
100
125
150
175
12
Supply Current, ICC (mA)
Supply Current, ICC (mA)
50
Supply Current (Off) versus Temperature
12
10
8
6
TA (°C)
-40
4
25
85
2
150
0
0
5
10
15
20
25
10
8
6
VCC (V)
4
12
4
18
2
0
30
24
-50
-25
0
Supply Voltage, VCC (V)
TA (°C)
350
-40
300
25
85
250
150
200
150
100
50
0
0
5
10
15
20
Output Current, IOUT (mA)
50
75
100
125
150
175
25
30
Output Voltage (On) versus Temperature
Low Output Voltage, VOUT(SAT) (mV)
450
400
25
Ambient Temperature, TA (°C)
Output Voltage (On) versus Output Current
Low Output Voltage, VOUT(SAT) (mV)
25
Ambient Temperature, TA (°C)
450
400
IOUT (mA)
10
350
15
300
20
250
25
200
150
100
50
0
-50
-25
0
25
50
75
100
125
150
175
Ambient Temperature, TA (°C)
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
6
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Output Current (Off) versus Temperature
Output Current, IOUT (mA)
5.0
4.0
3.0
2.0
1.0
0
-1.0
VOUT = 28 V
-2.0
-3.0
-4.0
-5.0
-50
-25
0
25
50
75
100
125
150
175
Ambient Temperature, TA (°C)
360° Repeatability versus Air Gap
360° Repeatability versus Air Gap
Sequential Region, 3 Rising Edges at Each TA
Sequential Region, 3 Falling Edges at Each TA
0.30
0.30
0.25
TA = 150°C
0.20
TA = 25°C
0.15
0.10
Specification Limit
0.05
360° Repeatability
6-Sigma, (°)
360° Repeatability
6-Sigma, (°)
0.25
TA = 150°C
0.20
TA = 25°C
0.15
0.10
Specification Limit
0.05
TA = –40°C
TA = –40°C
0
0
0.5
1.0
1.5
2.0
2.5
Air Gap, AG (mm)
3.0
3.5
4.0
0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Air Gap, AG (mm)
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
7
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Timing Accuracy versus Operational Speed
AG = 0.5 mm; relative to TA = 25°C, SROT = 1000 rpm
Signature Feature, Rising Edge
Signature Feature, Falling Edge
1.5
Relative Timing Accuracy (°)
Relative Timing Accuracy (°)
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
0
500
1000
1500
2000
1.0
0.5
0
-0.5
-1.0
-1.5
2500
0
Operational Speed, SROT (rpm)
1500
2000
2500
Sequential Features, Falling Edge
1.5
Relative Timing Accuracy (°)
1.5
Relative Timing Accuracy (°)
1000
Operational Speed, SROT (rpm)
Sequential Features, Rising Edge
1.0
0.5
0
-0.5
-1.0
-1.5
500
0
500
1000
1500
2000
2500
1.0
0.5
0
-0.5
-1.0
-1.5
0
Operational Speed, SROT (rpm)
500
1000
1500
2000
2500
Operational Speed, SROT (rpm)
Ambient Temperature, TA (°C)
–40
85
25
150
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
8
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Timing Accuracy versus Operational Speed
AG = 2.5 mm; relative to TA = 25°C, SROT = 1000 rpm
Signature Feature, Rising Edge
Signature Feature, Falling Edge
1.5
Relative Timing Accuracy (°)
Relative Timing Accuracy (°)
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
0
500
1000
1500
2000
1.0
0.5
0
-0.5
-1.0
-1.5
2500
0
Operational Speed, SROT (rpm)
1500
2000
2500
Sequential Features, Falling Edge
1.5
Relative Timing Accuracy (°)
1.5
Relative Timing Accuracy (°)
1000
Operational Speed, SROT (rpm)
Sequential Features, Rising Edge
1.0
0.5
0
-0.5
-1.0
-1.5
500
0
500
1000
1500
2000
2500
1.0
0.5
0
-0.5
-1.0
-1.5
0
Operational Speed, SROT (rpm)
500
1000
1500
2000
2500
Operational Speed, SROT (rpm)
Ambient Temperature, TA (°C)
–40
85
25
150
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
9
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Timing Accuracy versus Air Gap
TA = 25°C; relative to AG = 1.5 mm, SROT = 1000 rpm
Signature Feature, Rising Edge
Signature Feature, Falling Edge
1.5
Relative Timing Accuracy (°)
Relative Timing Accuracy (°)
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
0
0.5
1.0
1.5
2.0
2.5
1.0
0.5
0
-0.5
-1.0
-1.5
3.0
0
0.5
Air Gap, AG (rpm)
2.0
2.5
3.0
Sequential Features, Falling Edge
1.5
Relative Timing Accuracy (°)
1.5
Relative Timing Accuracy (°)
1.5
Air Gap, AG (rpm)
Sequential Features, Rising Edge
1.0
0.5
0
-0.5
-1.0
-1.5
1.0
0
0.5
1.0
1.5
2.0
2.5
3.0
1.0
0.5
0
-0.5
-1.0
-1.5
0
Air Gap, AG (rpm)
0.5
1.0
1.5
2.0
2.5
3.0
Air Gap, AG (rpm)
Operational Speed, SROT (rpm)
500
1500
1000
2000
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
10
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Timing Accuracy versus Ambient Temperature
AG = 0.5 mm; relative to TA = 25°C, SROT = 1000 rpm
Signature Feature, Rising Edge
Signature Feature, Falling Edge
1.5
Relative Timing Accuracy (°)
Relative Timing Accuracy (°)
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
-50
-25
0
25
50
75
100
125
150
1.0
0.5
0
-0.5
-1.0
-1.5
-50
175
-25
0
Ambient Temperature, TA (°C)
Sequential Features, Rising Edge
75
100
125
150
175
1.5
Relative Timing Accuracy (°)
Relative Timing Accuracy (°)
50
Sequential Features, Falling Edge
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
-50
25
Ambient Temperature, TA (°C)
-25
0
25
50
75
100
125
150
175
1.0
0.5
0
-0.5
-1.0
-1.5
-50
-25
0
25
50
75
100
125
150
175
Ambient Temperature, TA (°C)
Ambient Temperature, TA (°C)
Operational Speed, SROT (rpm)
500
1500
1000
2000
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
11
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Timing Accuracy versus Ambient Temperature
AG = 2.5 mm; relative to TA = 25°C, SROT = 1000 rpm
Signature Feature, Rising Edge
Signature Feature, Falling Edge
1.5
Relative Timing Accuracy (°)
Relative Timing Accuracy (°)
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
-50
-25
0
25
50
75
100
125
150
1.0
0.5
0
-0.5
-1.0
-1.5
-50
175
-25
0
Ambient Temperature, TA (°C)
Sequential Features, Rising Edge
75
100
125
150
175
1.5
Relative Timing Accuracy (°)
Relative Timing Accuracy (°)
50
Sequential Features, Falling Edge
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
-50
25
Ambient Temperature, TA (°C)
-25
0
25
50
75
100
125
150
175
1.0
0.5
0
-0.5
-1.0
-1.5
-50
-25
0
25
50
75
100
125
150
175
Ambient Temperature, TA (°C)
Ambient Temperature, TA (°C)
Operational Speed, SROT (rpm)
500
1500
1000
2000
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
12
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Timing Accuracy versus Operational Speed
TA = 25°C; relative to AG = 1.5 mm, SROT = 1000 rpm
Signature Feature, Rising Edge
Signature Feature, Falling Edge
1.5
Relative Timing Accuracy (°)
Relative Timing Accuracy (°)
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
0
500
1000
1500
2000
1.0
0.5
0
-0.5
-1.0
-1.5
2500
0
500
Operational Speed, SROT (rpm)
Sequential Features, Rising Edge
2000
2500
1.5
Relative Timing Accuracy (°)
Relative Timing Accuracy (°)
1500
Sequential Features, Falling Edge
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
1000
Operational Speed, SROT (rpm)
0
500
1000
1500
2000
1.0
0.5
0
-0.5
-1.0
-1.5
2500
0
Operational Speed, SROT (rpm)
500
1000
1500
2000
2500
Operational Speed, SROT (rpm)
Air Gap, AG (mm)
0.50
1.00
2.25
0.75
1.50
2.50
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
13
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Thermal Characteristics may require derating at maximum conditions, see Power Derating section
Characteristic
Symbol
Test Conditions*
Single layer PCB, with copper limited to solder pads
RθJA
Package Thermal Resistance
Single layer PCB, with copper limited to solder pads and 3.57
(23.03 cm2) copper area each side
in.2
Value
Unit
126
ºC/W
84
ºC/W
*Additional thermal information available on the Allegro website
Maximum Allowable V
CC(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
V CC(max)
(R θJA = 84 °C/W)
(R θJA= 126 °C/W)
V CC(min)
20
40
60
80
100
120
140
160
180
Temperature (°C)
Power Dissipation, PD (m W)
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
RQJA = 84 ºC/W
RQJA = 126 ºC/W
20
40
60
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
14
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Reference Target Characteristics
Reference Target 60+2
Test Conditions
Typ.
Unit
120
mm
Outside Diameter
Do
Outside diameter of target
Face Width
F
Breadth of tooth, with respect to
branded face
6
mm
Angular Tooth Thickness
t
Length of tooth, with respect to
branded face; measured at Do
3
deg.
Signature Region Angular Tooth Thickness
tSIG
Length of signature tooth, with
respect to branded face; measured
at Do
15
deg.
Angular Valley Thickness
tv
Length of valley, with respect to
branded face; measured at Do
3
deg.
Tooth Whole Depth
ht
3
mm
–
–
Material
Symbol Key
ØDO
ht
F
tV
Branded Face
of Package
Low Carbon Steel
SIG
Symbol
t,t
Characteristics
Air Gap
Signature Region
Reference Gear Magnetic Gradient Amplitude
With Reference to Air Gap
1200
Pin 4
1000
800
Pin 1
600
400
Branded Face
of Package
200
0
0.5
1
1.5
2
2.5
Reference Target
60+2
3
Air Gap (mm)
Reference Gear Magnetic Profile
Two Tooth-to-Valley Transitions
500
Air Gap
400
(mm)
0.50
0.75
1.00
1.25
1.50
1.75
2.00
2.25
2.50
2.75
3.00
300
Differential B* (G)
Peak-to-Peak Differential
Magnetic Flux Density, BDIFF (G)
1400
200
100
0
-100
-200
3.00 mm AG
-300
0.50 mm AG
-400
-500
0
2
4
6
8
10
12
Gear Rotation (°)
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
15
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Functional Description
Sensing Technology
The ATS627 contains a single-chip differential Hall-effect sensor
IC, a samarium cobalt pellet, and a flat ferrous pole piece (concentrator). As shown in figure 5, the Hall IC supports two Hall
elements, which sense the magnetic profile of the ferrous gear
target simultaneously, but at different points (spaced at a 2.2 mm
pitch), generating a differential internal analog voltage, VPROC,
that is processed for precise switching of the digital output signal.
The Hall IC is self-calibrating and also possesses a temperature
compensated amplifier and offset cancellation circuitry. The
built-in voltage regulator provides supply noise rejection throughout the operating voltage range. Changes in temperature do not
greatly affect this device due to the stable amplifier design and
the offset compensation circuitry. The Hall transducers and signal
processing electronics are integrated on the same silicon substrate, using a proprietary BiCMOS process.
Target Profiling During Operation
An operating device is capable of providing digital information
that is representative of the mechanical features of a rotating gear.
The waveform diagram in figure 7 presents the automatic translation of the mechanical profile, through the magnetic profile that
it induces, to the digital output signal of the ATS627. No additional optimization is needed and minimal processing circuitry is
required. This ease of use reduces design time and incremental
assembly costs for most applications.
Determining Output Signal Polarity
In figure 7 the top panel, labeled Mechanical Position, represents
the mechanical features of the target gear and orientation to the
device. The bottom panel, labeled Device Output Signal, displays
the square waveform corresponding to the digital output signal
that results from a rotating gear configured as shown in figure 6,
and electrically connected as in figure 9. That direction of rotation (of the gear side adjacent to the package face) is: perpendicular to the leads, across the face of the device, from the pin 1
side to the pin 4 side. This results in the IC output switching from
low state to high state as the leading edge of a tooth (a rising
mechanical edge, as detected by the IC) passes the package face.
In this configuration, the device output switches to its high polarity when a tooth is the target feature nearest to the package. If the
direction of rotation is reversed, so that the gear rotates from the
pin 4 side to the pin 1 side, then the output polarity inverts. That
is, the output signal goes high when a falling edge is detected,
and a valley is nearest to the package.
Mechanical Position (Target movement pin 1 to pin 4)
This tooth
sensed earlier
This tooth
sensed later
Target
(Gear)
Target Magnetic Profile
+B
Device Orientation to Target
Hall Element Pitch
Branded Face
Target (Gear)
Element Pitch
Hall Element 2
Dual-Element
Hall Effect Device
South Pole
Back-biasing Magnet
North Pole
(Pin 4 Side)
IC
Hall Element 1
Hall IC
Pole Piece
(Concentrator)
Sensor Branded Face
Pin 4
Side
(Package Top View)
Back-Biasing
Rare-Earth Pellet
Pin 1
Side
Device Internal Differential Analog Signal, VPROC
Case
(Pin 1 Side)
Figure 5. Relative motion of the target is detected by the dual
Hall elements in the Hall IC.
Branded Face
of Sensor
Rotating Target
BOP(#1)
BRP(#1)
BOP(#2)
BRP(#2)
Device Internal Switch State
On
Off
On
Off
Device Output Signal, VOUT
Pin 1
Pin 4
Figure 6. This left-to-right (pin 1 to pin 4) direction of target rotation results
in a high output state when a tooth of the target gear is nearest the
package face (see figure 3). A right-to-left (pin 4 to pin 1) rotation inverts
the output signal polarity.
Figure 7: The magnetic profile reflects the geometry of the target, allowing
the ATS627 to present an accurate digital output response.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
16
ATS627LSG
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
Undervoltage Lockout
When the supply voltage falls below the undervoltage lockout
voltage, VCC(UV) , the device enters Reset, where the output
state returns to the Power-On State (POS) until sufficient VCC
is supplied. This lockout feature prevents false signals, caused
by undervoltage conditions, from propagating to the output of
the IC.
Power Supply Protection
The device contains an on-chip regulator and can operate over a
wide VCC range. For devices that must operate from an unregulated power supply, transient protection must be added externally.
For applications using a regulated line, EMI/RFI protection
may still be required. Contact Allegro™ for information on the
circuitry needed for compliance with various EMC specifications.
Refer to figure 9 for an example of a basic application circuit.
Automatic Gain Control (AGC)
This feature allows the device to operate with an optimal internal
electrical signal, regardless of the air gap (within the AG specification). At power-on, the device determines the peak-to-peak
amplitude of the signal generated by the target.
This feature is also active in Running mode, though very conservatively invoked, to optimize the signal amplitude in the scenario
where signal amplitude during the initial calibration period is not
representative of the Running mode signal.
Automatic Offset Adjust (AOA)
The AOA circuitry automatically compensates for the effects of
chip, magnet, and installation offsets. This circuitry is continuously active, including during both Power-on mode and Running
mode, compensating for any offset drift (within the Allowable
User Induced Differential Offset). Continuous operation also
allows it to compensate for offsets induced by temperature variations over time. This circuitry works with the AGC during calibration to adjust VPROC in the internal range to allow the DACs
to acquire the signal peaks.
Bounded Update
The ATS627 continuously updates its switchpoints based on the
actual signal being received from the target. When the output
switches, the sensor resets the tracking DACs so that each proper
magnetic signal peak can be acquired. To prevent establishing
switchpoints on outlier signal maxima, tracking is limited, or
bounded, in magnitude. If such limiting were not applied, then
anomalous target features, such as bent, broken or misformed
teeth, could create significant output accuracy errors (see figure 8).
Running Mode Lockout
The ATS627 has a Running mode lockout feature to prevent
switching in response to small amplitude input signals that are
characteristic of vibration signals. The internal logic of the chip
interprets small signal amplitudes below a certain level to be the
result of target vibration. The output is held to the state present
prior to lockout, until the amplitude of the signal returns to normal operational levels.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
17
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Outlier
Bounded limit
enforced
Pp
PDAC
Tracking
Pp
Pp
V PRO
C
NDAC
Tracking
Np
Np
Np
Figure 8. Operation of Bounded Update method (for illustrative purposes only, values may not be to scale)
• Two DACs track the VPROC signal: PDAC tracks positive (high) peaks, and NDAC tracks negative (low)
peaks.
• The DACs track the VPROC signal until a peak is reached or the bounding limit is reached. Successive Pp
and Np values are used to establish the next switchpoint.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
18
ATS627LSG
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
Application Information
Power Derating
The device must be operated below the maximum junction temperature of the device, TJ(max). Under certain combinations of
peak conditions, reliable operation may require derating supplied
power or improving the heat dissipation properties of the application. This section presents a procedure for correlating factors
affecting operating TJ. (Thermal data is also available on the
Allegro MicroSystems website.)
The Package Thermal Resistance, RJA, is a figure of merit summarizing the ability of the application and the device to dissipate
heat from the junction (die), through all paths to the ambient air.
Its primary component is the Effective Thermal Conductivity,
K, of the printed circuit board, including adjacent devices and
traces. Radiation from the die through the device case, RJC, is
a relatively small component of RJA. Ambient air temperature,
TA, and air motion are significant external factors, damped by
overmolding.
The effect of varying power levels (Power Dissipation, PD), can
be estimated. The following formulas represent the fundamental
relationships used to estimate TJ, at PD.
PD = VIN × IIN

T = PD × RJA
TJ = TA + ΔT
(1)
(2)
Example: Reliability for VCC at TA = 150°C, package SG, using
single layer PCB.
Observe the worst-case ratings for the device, specifically:
RJA = 126°C/W, TJ(max) = 165°C, VCC(absmax) = 24 V, and
ICC = 12 mA.
Calculate the maximum allowable power level, PD(max). First,
invert equation 3:
T(max) = TJ(max) – TA = 165 °C – 150 °C = 15 °C
This provides the allowable increase to TJ resulting from internal
power dissipation. Then, invert equation 2:
PD(max) = T(max) ÷ RJA = 15°C ÷ 126 °C/W = 119 mW
Finally, invert equation 1 with respect to voltage:
VCC(est) = PD(max) ÷ ICC = 119 mW ÷ 12 mA = 9.9 V
The result indicates that, at TA, the application and device can
dissipate adequate amounts of heat at voltages ≤VCC(est).
Compare VCC(est) to VCC(max). If VCC(est) ≤ VCC(max), then reliable operation between VCC(est) and VCC(max) requires enhanced
RJA. If VCC(est) ≥ VCC(max), then operation between VCC(est) and
VCC(max) is reliable under these conditions.
(3)
For example, given common conditions such as: TA= 25°C,
VCC = 12 V, ICC = 7 mA, and RJA = 126 °C/W, then:
PD = VCC × ICC = 12 V × 7 mA = 84 mW

T = PD × RJA = 84 mW × 126 °C/W = 10.6°C
TJ = TA + T = 25°C + 10.6°C = 35.6°C
A worst-case estimate, PD(max), represents the maximum allowable power level (VCC(max), ICC(max)), without exceeding
TJ(max), at a selected RJA and TA.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
19
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Typical Application
VPU
VS
1
VCC
CBYPASS
ATS627
0.1 μF
3
(Recommended)
RPU
TEST
VOUT
Output
2
CL
GND
4
Figure 9. Basic typical application circuit
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
20
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Package SG, 4-Pin SIP
5.50±0.05
F 1.10
1.10 F
E
B
8.00±0.05
LLLLLLL
NNN
5.80±0.05
E1
E2
YYWW
Branded
Face
1.70±0.10
D
4.70±0.10
1
2
3
4
= Supplier emblem
L = Lot identifier
N = Last three numbers of device part number
Y = Last two digits of year of manufacture
W = Week of manufacture
A
0.60±0.10
Standard Branding Reference View
0.71±0.05
For Reference Only, not for tooling use (reference DWG-9002)
Dimensions in millimeters
A Dambar removal protrusion (16X)
+0.06
0.38 –0.04
B Metallic protrusion, electrically connected to pin 4 and substrate (both sides)
C Thermoplastic Molded Lead Bar for alignment during shipment
24.65±0.10
D Branding scale and appearance at supplier discretion
0.40±0.10
15.30±0.10
E
Active Area Depth, 0.43 mm
F
Hall elements (E1, E2), not to scale
1.0 REF
A
1.60±0.10
C
1.27±0.10
0.71±0.10
0.71±0.10
5.50±0.10
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
21
True Zero Speed, Low Jitter, High Accuracy
Position Sensor IC
ATS627LSG
Revision History
Revision
Revision Date
Description of Revision
Rev. 1
August 8, 2011
Add tr and tf definition, update derating example
Copyright ©2011-2013, 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
22
Similar pages