Texas Instruments | DRV5057-Q1 Automotive Linear Hall Effect Sensor With PWM Output | Datasheet | Texas Instruments DRV5057-Q1 Automotive Linear Hall Effect Sensor With PWM Output Datasheet

Texas Instruments DRV5057-Q1 Automotive Linear Hall Effect Sensor With PWM Output Datasheet
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DRV5057-Q1
SBAS645 – AUGUST 2019
DRV5057-Q1 Automotive Linear Hall Effect Sensor With PWM Output
1 Features
3 Description
•
The DRV5057-Q1 is a linear Hall effect sensor that
responds proportionally to magnetic flux density. The
device can be used for accurate position sensing in a
wide range of applications.
1
•
•
•
•
•
•
•
AEC-Q100 qualified for automotive applications
– Temperature grade 0: –40°C to 150°C
PWM-output linear Hall effect magnetic sensor
Operates from 3.3-V and 5-V power supplies
2-kHz clock output with 50% quiescent duty cycle
Magnetic sensitivity options (at VCC = 5 V):
– A1: 2%D/mT, ±21-mT range
– A2: 1%D/mT, ±42-mT range
– A3: 0.5%D/mT, ±84-mT range
– A4: 0.25%D/mT, ±168-mT range
Open-drain output with 20-mA sink capability
Compensation for magnet temperature drift
Industry standard package:
– Surface-mount SOT-23
2 Applications
•
•
•
•
•
•
•
Automotive position sensing
Brake, acceleration, clutch pedals
Torque sensors, gear shifters
Throttle position, height leveling
Powertrain and transmission components
Absolute angle encoding
Current sensing
The device operates from 3.3-V or 5-V power
supplies. When no magnetic field is present, the
output produces a clock with a 50% duty cycle. The
output duty cycle changes linearly with the applied
magnetic flux density, and four sensitivity options
maximize the output dynamic range based on the
required sensing range. North and south magnetic
poles produce unique outputs. The typical pulse-width
modulation (PWM) carrier frequency is 2 kHz.
Magnetic flux perpendicular to the top of the package
is sensed, and the two package options provide
different sensing directions.
Because the PWM signal is based on edge-to-edge
timing, signal integrity is maintained in the presence
of voltage noise or ground potential mismatch. This
signal is suitable for distance transmission in noisy
environments, and the always-present clock allows
the system controller to confirm there are good
interconnects. Additionally, the device features
magnet temperature compensation to counteract how
magnets drift for linear performance across a wide
–40°C to +150°C temperature range.
Device Information(1)
PART NUMBER
PACKAGE
DRV5057-Q1
SOT-23 (3)
BODY SIZE (NOM)
2.92 mm × 1.30 mm
(1) For all available packages, see the package option addendum
at the end of the data sheet.
Typical Schematic
VCC
Magnetic Response
PWM
Output
VDD
DRV5057-Q1
VCC
OUT
GND
Controller
Duty Cycle
8%
GPIO
25%
38%
50%
69%
75%
92%
VOH
VOL
Time
North
0 mT
South
Magnetic Field
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
DRV5057-Q1
SBAS645 – AUGUST 2019
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Table of Contents
1
2
3
4
5
6
7
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
4
6.1
6.2
6.3
6.4
6.5
6.6
6.7
4
4
4
4
5
5
6
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics...........................................
Magnetic Characteristics...........................................
Typical Characteristics ..............................................
7.4 Device Functional Modes........................................ 11
8
Application and Implementation ........................ 12
8.1 Application Information............................................ 12
8.2 Typical Applications ................................................ 14
8.3 What to Do and What Not to Do ............................. 20
9 Power Supply Recommendations...................... 21
10 Layout................................................................... 21
10.1 Layout Guidelines ................................................. 21
10.2 Layout Example .................................................... 21
11 Device and Documentation Support ................. 22
11.1
11.2
11.3
11.4
11.5
11.6
Detailed Description .............................................. 8
7.1 Overview ................................................................... 8
7.2 Functional Block Diagram ......................................... 8
7.3 Feature Description................................................... 8
Documentation Support ........................................
Receiving Notification of Documentation Updates
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
22
22
22
22
22
22
12 Mechanical, Packaging, and Orderable
Information ........................................................... 22
4 Revision History
2
DATE
REVISION
NOTES
August 2019
*
Initial release.
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5 Pin Configuration and Functions
DBZ Package
3-Pin SOT-23
Top View
VCC
1
3
OUT
GND
2
Not to scale
Pin Functions
PIN
NAME
NO.
TYPE
DESCRIPTION
GND
3
Ground
Ground reference
OUT
2
Output
Analog output
VCC
1
Power
Power supply. Connect this pin to a ceramic capacitor to ground with a value of at least 0.01 µF.
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6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1)
VCC
MIN
MAX
Power supply voltage
VCC
–0.3
7
Output voltage
OUT
–0.3
Output current
OUT
UNIT
V
6
V
30
mA
B
Magnetic flux density
Unlimited
TJ
Operating junction temperature
–40
170
°C
Tstg
Storage temperature
–65
150
°C
(1)
T
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
6.2 ESD Ratings
VALUE
V(ESD)
(1)
Electrostatic discharge
Human body model (HBM), per AEC Q100-002 (1)
HBM ESD classification level 2
±3000
Charged device model (CDM), per AEC Q100-011
CDM ESD classification level C5
±750
UNIT
V
AEC Q100-002 indicates that HBM stressing shall be in accordance with the ANSI/ESDA/JEDEC JS-001 specification.
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
VCC
Power-supply voltage (1)
VO
Output pullup voltage
IO
Output continuous current
TA
Operating ambient temperature (2)
(1)
(2)
MIN
MAX
3
3.63
UNIT
4.5
5.5
0
5.5
V
0
20
mA
–40
150
°C
V
There are two isolated operating VCC ranges. For more information see the Operating VCC Ranges section.
Power dissipation and thermal limits must be observed.
6.4 Thermal Information
DRV5057-Q1
THERMAL METRIC (1)
SOT-23 (DBZ)
UNIT
3 PINS
RθJA
Junction-to-ambient thermal resistance
170
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
66
°C/W
RθJB
Junction-to-board thermal resistance
49
°C/W
ΨJT
Junction-to-top characterization parameter
1.7
°C/W
ΨJB
Junction-to-board characterization parameter
48
°C/W
(1)
4
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
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6.5 Electrical Characteristics
for VCC = 3 V to 3.63 V and 4.5 V to 5.5 V, over operating free-air temperature range (unless otherwise noted)
PARAMETER
TEST CONDITIONS
ICC
Operating supply current
tON
Power-on time (see Figure 15) (1)
fPWM
PWM carrier frequency
DJ
Duty cycle peak-to-peak jitter
IOZ
High-impedance output leakage current VCC = 5 V
VOL
Low-level output voltage
(1)
(2)
(3)
MIN
TYP
B (2) = 0 mT, no load on OUT
1.8
From change in B to change in OUT
MAX
6
10
0.6
0.9
ms
2.0
2.2
kHz
0.15
mA
%D (3)
±0.1
IOUT = 20 mA
UNIT
100
nA
0.4
V
MAX
UNIT
92
%D (1)
tON is the time from when VCC goes above 3 V until the first rising edge of the first valid pulse.
B is the applied magnetic flux density.
This unit is a percentage of duty cycle.
6.6 Magnetic Characteristics
for VCC = 3 V to 3.63 V and 4.5 V to 5.5 V, over operating free-air temperature range (unless otherwise noted)
PARAMETER
DL
TEST CONDITIONS
Linear duty cycle range
Clamped-low duty cycle
B
DCH
Clamped-high duty cycle
B > 250 mT
DQ
Quiescent duty cycle (3)
B = 0 mT, TA = 25°C, VCC = 3.3 V or 5 V
Quiescent duty cycle lifetime drift
High-temperature operating stress for
1000 hours
< –250 mT
VCC = 5 V,
TA = 25°C
S
TYP
8
(2)
DCL
VQΔL
MIN
Sensitivity
VCC = 3.3 V,
TA = 25°C
VCC = 5 V,
TA = 25°C
5.3
6
6.7
93.3
94
94.7
43
50
57
%D
%D
< 0.5
DRV5057A1-Q1
1.88
DRV5057A2-Q1
DRV5057A3-Q1
%
2
2.12
0.94
1
1.06
0.47
0.5
0.53
DRV5057A4-Q1
0.23
0.25
0.27
DRV5057A1-Q1
1.13
1.2
1.27
DRV5057A2-Q1
0.56
0.6
0.64
DRV5057A3-Q1
0.28
0.3
0.32
DRV5057A4-Q1
0.138
0.15
0.162
DRV5057A1-Q1
±21
DRV5057A2-Q1
±42
DRV5057A3-Q1
±84
DRV5057A4-Q1
±168
%D/mT
BL
Linear magnetic flux density sensing
range (3) (4)
STC
Sensitivity temperature compensation
for magnets (5)
SLE
Sensitivity linearity error (3)
Output duty cycle is within DL
±1
%
RSE
Sensitivity error over operating VCC
range
Output duty cycle is within DL
±1
%
SΔL
Quiescent error over operating VCC
range
< 0.5
%
(1)
(2)
(3)
(4)
(5)
0.12
mT
%/°C
This unit is a percentage of duty cycle.
B is the applied magnetic flux density.
See the Sensitivity Linearity section.
BL describes the minimum linear sensing range at 25°C taking into account the maximum VQ and sensitivity tolerances.
STC describes the rate the device increases Sensitivity with temperature. For more information, see the Sensitivity Temperature
Compensation for Magnets section and Figure 4 to Figure 11.
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6.7 Typical Characteristics
for TA = 25°C (unless otherwise noted)
2.2
1.3
1.2
2
5057A1
5057A2
5057A3
5057A4
1.6
1.4
1.1
Sensitivity (%D/mT)
Sensitivity (%D/mT)
1.8
1.2
1
0.8
0.6
0.9
0.8
0.7
0.6
0.5
0.4
0.4
0.3
0.2
0
4.5
5057A1
5057A2
5057A3
5057A4
1
0.2
0.1
4.6
4.7
4.8
4.9
5
5.1
Supply (V)
5.2
5.3
5.4
5.5
3
3.1
3.2
D010
VCC = 5.0 V
Figure 1. Sensitivity vs Supply Voltage
3.5
3.6
D011
Figure 2. Sensitivity vs Supply Voltage
2.5
VCC = 3.3 V
VCC = 5.0 V
9
2.25
2
Sensitivity (%D/mT)
8
Supply Current (mA)
3.4
VCC = 3.3 V
10
7
6
5
4
1.75
1.5
1.25
1
0.75
3
0.5
2
0.25
1
-40
3.3
Supply (V)
-20
0
20
40
60
80
Temperature (qC)
100
120
0
-40
140
+STD
AVG
-STD
-20
0
20
D012
40
60
80
Temperature (qC)
100
120
140
D014
DRV5057A1-Q1, VCC = 5.0 V
Figure 3. Supply Current vs Temperature
Figure 4. Sensitivity vs Temperature
2.5
+STD
AVG
-STD
2.25
Sensitivity (%D/mT)
Sensitivity (%D/mT)
2
1.75
1.5
1.25
1
0.75
0.5
0.25
0
-40
-20
0
20
40
60
80
Temperature (qC)
100
120
140
1.5
1.4
1.3
1.2
1.1
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
-40
+STD
AVG
-STD
-20
D013
DRV5057A1-Q1, VCC = 3.3 V
20
40
60
80
Temperature (qC)
100
120
140
D005
DRV5057A2-Q1, VCC = 5.0 V
Figure 5. Sensitivity vs Temperature
6
0
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Figure 6. Sensitivity vs Temperature
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Typical Characteristics (continued)
1.5
1.4
1.3
1.2
1.1
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
-40
1
+STD
AVG
-3STD
+STD
AVG
-3STD
0.9
0.8
Sensitivity (%D/mT)
Sensitivity (%D/mT)
for TA = 25°C (unless otherwise noted)
0.7
0.6
0.5
0.4
0.3
0.2
0.1
-20
0
20
40
60
80
Temperature (qC)
100
120
0
-40
140
-20
0
DRV5057A2-Q1, VCC = 3.3 V
Figure 7. Sensitivity vs Temperature
100
120
140
D003
Figure 8. Sensitivity vs Temperature
0.5
+STD
AVG
-3STD
0.9
0.8
0.4
0.7
0.6
0.5
0.4
0.3
0.35
0.3
0.25
0.2
0.15
0.2
0.1
0.1
0.05
-20
0
20
40
60
80
Temperature (qC)
100
120
+STD
AVG
-3STD
0.45
Sensitivity (%D/mT)
Sensitivity (%D/mT)
40
60
80
Temperature (qC)
DRV5057A3-Q1, VCC = 5.0 V
1
0
-40
20
D006
0
-40
140
-20
0
20
D004
DRV5057A3-Q1, VCC = 3.3 V
40
60
80
Temperature (qC)
100
120
140
D001
DRV5057A4-Q1, VCC = 5.0 V
Figure 9. Sensitivity vs Temperature
Figure 10. Sensitivity vs Temperature
0.5
+STD
AVG
-3STD
0.45
Sensitivity (%D/mT)
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
-40
-20
0
20
40
60
80
Temperature (qC)
100
120
140
D002
DRV5057A4-Q1, VCC = 3.3 V
Figure 11. Sensitivity vs Temperature
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7 Detailed Description
7.1 Overview
The DRV5057-Q1 is a 3-pin pulse-width modulation (PWM) output Hall effect sensor with fully integrated signal
conditioning, temperature compensation circuits, mechanical stress cancellation, and amplifiers. The device
operates from 3.3-V and 5-V (±10%) power supplies, measures magnetic flux density, and outputs a pulse-width
modulated, 2-kHz digital signal.
7.2 Functional Block Diagram
Element Bias
Bandgap
Reference
VCC
0 …F
Offset Cancellation
Trim Registers
GND
Temperature
Compensation
VCC
Precision
Amplifier
PWM Driver
OUT
7.3 Feature Description
7.3.1 Magnetic Flux Direction
As shown in Figure 12, the DRV5057-Q1 is sensitive to the magnetic field component that is perpendicular to the
top of the package.
B
SOT-23
PCB
Figure 12. Direction of Sensitivity
8
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Feature Description (continued)
Magnetic flux that travels from the bottom to the top of the package is considered positive in this document. This
condition exists when a south magnetic pole is near the top (marked-side) of the package. Magnetic flux that
travels from the top to the bottom of the package results in negative millitesla values. Figure 13 shows flux
direction.
N
S
PCB
Figure 13. Flux Direction for Positive B
7.3.2 Sensitivity Linearity
The device produces a pulse-width modulated digital signal output. As shown in Figure 14, the duty-cycle of the
PWM output signal is proportional to the magnetic field detected by the Hall element of the device. If there is no
magnetic field present, the duty cycle is 50%. The DRV5057-Q1 can detect both magnetic north and south poles.
The output duty cycle maintains a linear relationship with the input magnetic field from 8% to 92%.
PWM
Output
Duty Cycle
8%
25%
38%
50%
69%
75%
92%
VOH
VOL
Time
North
0 mT
South
Magnetic Field
Figure 14. Magnetic Response
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Feature Description (continued)
7.3.3 Operating VCC Ranges
The DRV5057-Q1 has two recommended operating VCC ranges: 3 V to 3.63 V and 4.5 V to 5.5 V. When VCC is
in the middle region between 3.63 V to 4.5 V, the device continues to function but sensitivity is less known
because there is a crossover threshold near 4 V that adjusts device characteristics.
7.3.4 Sensitivity Temperature Compensation for Magnets
Magnets generally produce weaker fields as temperature increases. The DRV5057-Q1 has a temperature
compensation feature that is designed to directly compensate the average drift of neodymium (NdFeB) magnets
and partially compensate ferrite magnets. The residual induction (Br) of a magnet typically reduces by 0.12%/°C
for NdFeB, and 0.20%/°C for ferrite. When the operating temperature of a system is reduced, temperature drift
errors are also reduced.
7.3.5 Power-On Time
After the VCC voltage is applied, the DRV5057-Q1 requires a short initialization time before the output is set. The
parameter tON describes the time from when VCC crosses 3 V until OUT is within 5% of VQ, with 0 mT applied
and no load attached to OUT. Figure 15 shows this timing diagram.
VCC
3V
tON
time
Output
95% × V Q
Invalid
time
Figure 15. tON Definition
10
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Feature Description (continued)
7.3.6 Hall Element Location
Figure 16 shows the location of the sensing element inside each package option.
SOT-23
Top View
SOT-23
Side View
centered
±50 µm
650 µm
±80 µm
Figure 16. Hall Element Location
7.4 Device Functional Modes
The DRV5057-Q1 has one mode of operation that applies when the Recommended Operating Conditions are
met.
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8 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
8.1.1 Selecting the Sensitivity Option
Select the highest DRV5057-Q1 sensitivity option that can measure the required range of magnetic flux density
so that the output voltage swing is maximized.
Larger-sized magnets and farther sensing distances can generally enable better positional accuracy than very
small magnets at close distances, because magnetic flux density increases exponentially with the proximity to a
magnet. TI created an online tool to help with simple magnet calculations on the DRV5057-Q1 product folder.
8.1.2 Decoding a PWM
A PWM output helps system designers drive signals for long distances in noisy environments, with the ability to
retrieve the signal accurately. A decoder is employed at the load to retrieve the analog magnetic signal. Two
different methods of decoding are discussed in this section.
8.1.2.1 Decoding a PWM (Digital)
8.1.2.1.1 Capture and Compare Timer Interrupt
Many microcontrollers have a capture and compare timer mode that can simplify the PWM decoding process.
Use the timer in capture and compare mode with an interrupt that triggers on both the rising and falling edges of
the signal to obtain both the relative high (on) and low (off) time of the PWM. Make sure that the timer period is
significantly faster than the period of the PWM, based on the desired resolution. Calculate the percent duty cycle
(%D) of the PWM with Equation 1 by using the relative on and off time of the signal.
OnTime
%D
u 100
OnTime OffTime
(1)
8.1.2.1.2 Oversampling and Counting With a Timer Interrupt
If a capture and compare timer is not available, a standard timer interrupt and a counter can be used. Configure
the timer interrupt to be significantly faster than the period of the PWM, based on the desired resolution. Count
how many times the timer interrupts while the signal is high (OnTime), then count how many times the timer
interrupts while the signal is low (OffTime). Then use Equation 1 to calculate the duty cycle.
8.1.2.1.3 Accuracy and Resolution
The accuracy and resolution for the methods described in the Capture and Compare Timer Interrupt and
Oversampling and Counting With a Timer Interrupt sections depends significantly on the timer sampling
frequency. Equation 2 calculates the least significant bit of the duty cycle (%DLSB) based on the chosen timer
sampling frequency.
PWM frequency
%D LSB
u 100
TIMER frequency
(2)
For example, with a 2-kHz PWM and a 400-kHz sampling frequency, the %DLSB is:
(2 kHz / 400 kHz) × 100 = 0.5%DLSB
If the sampling frequency in increased to 2-MHz, the %DLSB is improved to be:
(2 MHz / 400 kHz) × 100 = 0.1%DLSB
However, accuracy and resolution are still subject to noise and sensitivity.
12
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Application Information (continued)
8.1.2.2 Decoding a PWM (Analog)
If an analog signal is needed at the end of a large travel distance, first use a microcontroller to digitally decode
the PWM, then use a DAC to produce the analog signal. If an analog signal is needed after a short signal travel
distance, use an analog output device, such as the DRV5055-Q1.
If an analog signal is needed at the end of a large travel distance and a microcontroller is unavailable, use a lowpass filter to convert the PWM signal into an analog voltage, as shown in Figure 17. When using this method,
note the following:
• A ripple appears at the analog voltage output, causing a decrease in accuracy. The ripple intensity and
frequency depend on the values chosen for R and C in the filter.
• The minimum and maximum voltages of the PWM must be known to calculate the magnetic field strength
from the analog voltage. Thus, if the signal is traveling a large distance, then the minimum and maximum
values must be either measured or buffered back to a known value.
PWM Signal
Analog Signal
R
C
Figure 17. Low-Pass RC Filter
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8.2 Typical Applications
The DRV557-Q1 is a very robust linear position sensor for applications such as throttle positions, brakes, and
clutch pedals. In linear position applications, depending on the mechanical placement and design limitations, two
common types of magnet orientations are selected: full-swing and half-swing.
8.2.1 Full-Swing Orientation Example
In the full-swing orientation, a magnet travels in parallel to the DRV5057-Q1 surface. In this case, the magnetic
range extends from south polarity to north polarity, and allows the DRV5057-Q1 to use the full linear magnetic
flux density sensing range.
S
N
Figure 18. Full-Swing Orientation Example
8.2.1.1 Design Requirements
Use the parameters listed in Table 1 for this design example.
Table 1. Design Parameters
14
DESIGN PARAMETER
EXAMPLE VALUE
Device
DRV5057-Q1
VCC
5V
Magnet
Cylinder: 4.7625-mm diameter, 12.7-mm thick,
neodymium N52, Br = 1480 mT
Travel distance
10 mm
Desired accuracy
< 0.1 mm
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8.2.1.2 Detailed Design Procedure
Linear Hall effect sensors provide flexibility in mechanical design because many possible magnet orientations
and movements produce a usable response from the sensor. Figure 18 illustrates one of the most common
orientations that uses the full north to south range of the sensor and causes a close-to-linear change in magnetic
flux density as the magnet moves across the sensor. Figure 19 illustrates the close-to-linear change in magnetic
field present at the sensor as the magnet moves a given distance across the sensor. The usable linear region is
close to but less than the length (thickness) of the magnet.
When designing a linear magnetic sensing system, always consider these three variables: the magnet, sensing
distance, and the range of the sensor. Select the DRV5057-Q1 with the highest sensitivity possible based on the
system distance requirements without railing the sensor PWM output. To determine the magnetic flux density the
sensor receives at the various positions of the magnet, use a magnetic field calculator or simulation software,
referring to magnet specifications, and testing.
Determine if the desired accuracy is met by comparing the maximum allowed duty cycle least significant bit
(%DLSBmax) with the noise level (PWM jitter) of the device. Equation 3 calculates the %DLSBmax by taking into
account the used length of the linear region (travel distance), the desired resolution, and the output PWM swing
(within the linear duty cycle range).
%D swing
%D LSBmax
u Re solution
Travel Dis tance
(3)
Thus, with this example (and a linear duty cycle range of 8%D to 92%D), using Equation 3 gives (92 – 8) / (10) ×
0.1 = 0.84%DLSBmax. This value is larger than the 0.1%D jitter, and therefore the desired accuracy can be
achieved by using Equation 2 to select a %DLSB that is equal to or less than 0.84. Then, simply calibrate the
magnet position to align the sensor output along the movement path.
8.2.1.3 Application Curve
Figure 19 shows the magnetic field present at the sensor as the magnet passes by as described in Figure 18.
The change in distance from the trough to the peak is approximately the length (thickness) of the magnet. B
changes based on the strength of the magnet and how close the magnet is to the sensor.
B
5
-9
9
Distance
D015
Figure 19. Magnetic Field vs Distance
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8.2.2 Half-Swing Orientation Example
In the half-swing orientation, a magnet travels perpendicular to the DRV5057-Q1 surface. In this case, the
magnetic range extends only to either the south or north pole, using only half of the DRV5057-Q1 linear
magnetic flux density sensing range.
Mechanical Component
N
S
PCB
Figure 20. Half-Swing Orientation Example
8.2.2.1 Design Requirements
Use the parameters listed in Table 2 for this design example.
Table 2. Design Parameters
DESIGN PARAMETER
EXAMPLE VALUE
Device
DRV5057-Q1
VCC
5V
Magnet
Cylinder: 4.7625 mm diameter, 12.7 mm thick,
Neodymium N52, Br = 1480 mT
Travel distance
5 mm
Desired accuracy
< 0.1 mm
8.2.2.2 Detailed Design Procedure
As illustrated in Figure 20, this design example consists of a mechanical component that moves back and forth,
an embedded magnet with the south pole facing the printed-circuit board, and a DRV5057-Q1. The DRV5057-Q1
outputs a PWM that describes the precise position of the component. The component must not contain
ferromagnetic materials such as iron, nickel, and cobalt because these materials change the magnetic flux
density at the sensor.
When designing a linear magnetic sensing system, always consider these three variables: the magnet, sensing
distance, and the range of the sensor. Select the DRV5057-Q1 with the highest sensitivity possible based on the
system distance requirements without railing the sensor PWM output. To determine the magnetic flux density the
sensor receives at the various positions of the magnet, use a magnetic field calculator or simulation software,
referring to magnet specifications, and testing.
16
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Magnets are made from various ferromagnetic materials that have tradeoffs in cost, drift with temperature,
absolute maximum temperature ratings, remanence or residual induction (Br), and coercivity (Hc). The Br and the
dimensions of a magnet determine the magnetic flux density (B) produced in 3-dimensional space. For simple
magnet shapes, such as rectangular blocks and cylinders, there are simple equations that solve B at a given
distance centered with the magnet. Figure 21 shows diagrams for Equation 4 and Equation 5.
Thickness
Thickness
Width
Distance
Length
S
S
Distance
N
B
N
Diameter
B
Figure 21. Rectangular Block and Cylinder Magnets
Use Equation 4 for the rectangular block shown in Figure 21:
B=
Br
Œ
( (
WL
arctan
2
2
2D 4D + W + L
2
)
± arctan
Use Equation 5 for the cylinder illustrated in Figure 21:
Br
D+T
D
±
B=
2
2
2
(0.5C) + (D + T)
(0.5C)2 + D2
(
(
WL
2(D + T) 4(D + T)2 + W2 + L2
))
(4)
)
where:
•
•
•
•
•
W is width
L is length
T is thickness (the direction of magnetization)
D is distance
C is diameter
(5)
This example uses a cylinder magnet; therefore, Equation 5 can be used to create a lookup table for the
distances from a specific magnet based on a magnetic field strength. Figure 22 shows a magnetic field from 0
mm to 16 mm with the magnet defined in Table 2 as C = 4.7625 mm, T = 12.7 mm, and Br = 1480 mT.
200
180
160
B (mT)
140
120
100
80
60
40
20
0
0
1
2
3
4
5
6 7 8 9 10 11 12 13 14 15 16
Distance (mm)
D009
Figure 22. Magnetic Field vs Distance
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In this setup, each gain version of the sensor produces the corresponding duty cycle shown in Figure 23 for
0 mm to 16 mm.
100
DRV5057A1
DRV5057A2
DRV5057A3
DRV5057A4
95
Duty Cycle (%)
90
85
80
75
70
65
60
55
50
0
1
2
3
4
5
6 7 8 9 10 11 12 13 14 15 16
Distance (mm)
D008
Figure 23. %D vs South Pole Distance (All Gains)
With a desired 5-mm movement swing, select the DRV5057-Q1 with the largest possible sensitivity that fits the
system requirements for the magnet distance to the sensor. Assume that for this example, because of
mechanical restrictions, the magnet at the nearest point to the sensor must be selected to be within 5 mm to
8 mm. The largest sensitivity option (A1) does not work in this situation because the device output is railed at the
farthest allowed distance of 8 mm. The A2 version is not railed at this point, and is therefore the sensor selected
for this example. Choose the closest point of the magnet to the sensor to be a distance that allows the magnet to
get as close to the sensor as possible without railing but stays within the selectable 5-mm to 8-mm allowed
range. Because the A2 version rails at approximately 6 mm, choose a closest distance of 6.5 mm to allow for a
little bit of margin. With this choice, Figure 24 shows the %D response at the sensor across the full movement
range.
100
DRV5057A2
95
Duty Cycle (%)
90
85
80
75
70
65
60
55
50
6.5
7
7.5
8
8.5
9
9.5
Distance (mm)
10
10.5
11
11.5
D007
Figure 24. %D vs South Pole Distance (Gain A2)
18
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The magnetic field strength is calculated using Equation 6, where a negative number represents the opposite
pole (in this example a south pole is over the sensor, causing the results to be a positive number).
%D 50
B
Gain
(6)
For example, if the A2 version of the DRV5057-Q1 measured a duty cycle of %D = 74.6% using Equation 1 ,
then the magnetic field strength present at the sensor is (74.6 – 50) / 1 = 24.6 mT.
Using the lookup table that was used to create the plot in Figure 22, the distance from the magnet at 24.6 mT is
D ≈ 8.2 mm.
For more accurate results, the lookup table can be calibrated along the movement path of the magnet.
Additionally, instead of using the calibrated lookup table for each measurement, consider using a best-fit
polynomial equation from the curve for the desired movement range to calculate D in terms of B.
The curve in Figure 24 is not linear; therefore, the achievable accuracy varies for each position along the
movement path. The location with the worst accuracy is where there is the smallest change in output for a given
amount of movement, which in this example is where the magnet is farthest from the sensor (at 11.5 mm).
Determine if the desired accuracy is met by checking if the needed %DLSB at this location for the specified
accuracy is greater than the noise level (PWM jitter) of 0.1%D. Thus, with a desired accuracy of 0.1 mm, the
needed %DLSB is the change in %D between 11.4 mm and 11.5 mm. Using the lookup table to find B and then
solving for %D in Equation 6, at 11.5 mm, B = 11.815 mT (which equates to 61.815%D), and at 11.4 mm B =
12.048 mT (which equates to 62.048%D). The difference in %D between these two points is 62.048 – 61.815 =
0.223%DLSB. This value is larger than the 0.1%D jitter, so the desired accuracy can be met as long as a %DLSB
is selected that is equal to or less than 0.223 using Equation 2.
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8.3 What to Do and What Not to Do
The Hall element is sensitive to magnetic fields that are perpendicular to the top of the package. Therefore, to
correctly detect the magnetic field, make sure to use the correct magnet orientation for the sensor. Figure 25
shows correct and incorrect orientation.
CORRECT
N
S
S
N
N
S
INCORRECT
N
S
Figure 25. Correct and Incorrect Magnet Orientation
20
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9 Power Supply Recommendations
Use a decoupling capacitor placed close to the device to provide local energy with minimal inductance. Use a
ceramic capacitor with a value of at least 0.01 µF.
10 Layout
10.1 Layout Guidelines
Magnetic fields pass through most nonferromagnetic materials with no significant disturbance. Embedding Hall
effect sensors within plastic or aluminum enclosures and sensing magnets on the outside is common practice.
Magnetic fields also easily pass through most printed-circuit boards, which makes placing the magnet on the
opposite side possible.
10.2 Layout Example
VCC
GND
OUT
Figure 26. Layout Example
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11 Device and Documentation Support
11.1 Documentation Support
11.1.1 Related Documentation
For related documentation see the following:
• Texas Instruments, Using Linear Hall Effect Sensors to Measure Angle tech note
• Texas Instruments, Incremental Rotary Encoder Design Considerations tech note
• Texas Instruments, DRV5055 Ratiometric Linear Hall Effect Sensor data sheet
11.2 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper
right corner, click on Alert me to register and receive a weekly digest of any product information that has
changed. For change details, review the revision history included in any revised document.
11.3 Community Resources
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective
contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of
Use.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
11.4 Trademarks
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
11.5 Electrostatic Discharge Caution
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
11.6 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
12 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
22
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PACKAGE OPTION ADDENDUM
www.ti.com
22-Aug-2019
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
Op Temp (°C)
Device Marking
(4/5)
DRV5057A1EDBZRQ1
ACTIVE
SOT-23
DBZ
3
3000
Green (RoHS
& no Sb/Br)
CU SN
Level-3-260C-168 HR
-40 to 150
57A1Z
DRV5057A2EDBZRQ1
ACTIVE
SOT-23
DBZ
3
3000
Green (RoHS
& no Sb/Br)
CU SN
Level-3-260C-168 HR
-40 to 150
57A2Z
DRV5057A3EDBZRQ1
ACTIVE
SOT-23
DBZ
3
3000
Green (RoHS
& no Sb/Br)
CU SN
Level-3-260C-168 HR
-40 to 150
57A3Z
DRV5057A4EDBZRQ1
ACTIVE
SOT-23
DBZ
3
3000
Green (RoHS
& no Sb/Br)
CU SN
Level-3-260C-168 HR
-40 to 150
57A4Z
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based
flame retardants must also meet the <=1000ppm threshold requirement.
(3)
MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4)
There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5)
Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
(6)
Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish
value exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
Addendum-Page 1
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
22-Aug-2019
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
OTHER QUALIFIED VERSIONS OF DRV5057-Q1 :
• Catalog: DRV5057
NOTE: Qualified Version Definitions:
• Catalog - TI's standard catalog product
Addendum-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
23-Aug-2019
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
B0
(mm)
K0
(mm)
P1
(mm)
DRV5057A1EDBZRQ1
SOT-23
DBZ
3
3000
180.0
8.4
DRV5057A2EDBZRQ1
SOT-23
DBZ
3
3000
180.0
DRV5057A3EDBZRQ1
SOT-23
DBZ
3
3000
180.0
DRV5057A4EDBZRQ1
SOT-23
DBZ
3
3000
180.0
3.15
2.77
1.22
4.0
8.0
Q3
8.4
3.15
2.77
1.22
4.0
8.0
Q3
8.4
3.15
2.77
1.22
4.0
8.0
Q3
8.4
3.15
2.77
1.22
4.0
8.0
Q3
Pack Materials-Page 1
W
Pin1
(mm) Quadrant
PACKAGE MATERIALS INFORMATION
www.ti.com
23-Aug-2019
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
DRV5057A1EDBZRQ1
SOT-23
DBZ
3
3000
213.0
191.0
35.0
DRV5057A2EDBZRQ1
SOT-23
DBZ
3
3000
213.0
191.0
35.0
DRV5057A3EDBZRQ1
SOT-23
DBZ
3
3000
213.0
191.0
35.0
DRV5057A4EDBZRQ1
SOT-23
DBZ
3
3000
213.0
191.0
35.0
Pack Materials-Page 2
4203227/C
PACKAGE OUTLINE
DBZ0003A
SOT-23 - 1.12 mm max height
SCALE 4.000
SMALL OUTLINE TRANSISTOR
C
2.64
2.10
1.4
1.2
PIN 1
INDEX AREA
1.12 MAX
B
A
0.1 C
1
0.95
3.04
2.80
1.9
3X
3
0.5
0.3
0.2
2
(0.95)
C A B
0.25
GAGE PLANE
0 -8 TYP
0.10
TYP
0.01
0.20
TYP
0.08
0.6
TYP
0.2
SEATING PLANE
4214838/C 04/2017
NOTES:
1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing
per ASME Y14.5M.
2. This drawing is subject to change without notice.
3. Reference JEDEC registration TO-236, except minimum foot length.
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EXAMPLE BOARD LAYOUT
DBZ0003A
SOT-23 - 1.12 mm max height
SMALL OUTLINE TRANSISTOR
PKG
3X (1.3)
1
3X (0.6)
SYMM
3
2X (0.95)
2
(R0.05) TYP
(2.1)
LAND PATTERN EXAMPLE
SCALE:15X
SOLDER MASK
OPENING
METAL
SOLDER MASK
OPENING
METAL UNDER
SOLDER MASK
0.07 MIN
ALL AROUND
0.07 MAX
ALL AROUND
NON SOLDER MASK
DEFINED
(PREFERRED)
SOLDER MASK
DEFINED
SOLDER MASK DETAILS
4214838/C 04/2017
NOTES: (continued)
4. Publication IPC-7351 may have alternate designs.
5. Solder mask tolerances between and around signal pads can vary based on board fabrication site.
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EXAMPLE STENCIL DESIGN
DBZ0003A
SOT-23 - 1.12 mm max height
SMALL OUTLINE TRANSISTOR
PKG
3X (1.3)
1
3X (0.6)
SYMM
3
2X(0.95)
2
(R0.05) TYP
(2.1)
SOLDER PASTE EXAMPLE
BASED ON 0.125 THICK STENCIL
SCALE:15X
4214838/C 04/2017
NOTES: (continued)
6. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate
design recommendations.
7. Board assembly site may have different recommendations for stencil design.
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AND WITH ALL FAULTS, AND DISCLAIMS ALL WARRANTIES, EXPRESS AND IMPLIED, INCLUDING WITHOUT LIMITATION ANY
IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT OF THIRD
PARTY INTELLECTUAL PROPERTY RIGHTS.
These resources are intended for skilled developers designing with TI products. You are solely responsible for (1) selecting the appropriate
TI products for your application, (2) designing, validating and testing your application, and (3) ensuring your application meets applicable
standards, and any other safety, security, or other requirements. These resources are subject to change without notice. TI grants you
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Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
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