ALS31300
3-D Linear Hall-Effect Sensor
with I2C Output and Advanced Low Power Management
FEATURES AND BENEFITS
DESCRIPTION
• X- and Y-axis sensing of joystick position
• Z-axis sensing of “crouch” or push button motion
• Capable of operating with back-bias magnets for joystick
return-to-zero
• Ideal for battery-powered, low-voltage applications
□□ 2.65 to 3.5 V single supply operation
□□ 1 MHz I2C compatibility down to 1.8 V
□□ 14 nA (typ) Sleep ICC
□□ 12 µA to 2 mA ICC (typ) in low-power duty cycle mode
• Industry standard I2C interface for easy system integration
□□ Up to 1 MHz (Fast Mode+) I2C communication
□□ 16 selectable addresses via external resistor divider
□□ 127 available address configurable via EEPROM
• On-chip EEPROM
□□ Stores factory- and user-configured settings
□□ 78 bits of user EEPROM for additional storage
□□ On-chip charge pump for easy programming
The ALS31300 three-axis linear Hall-effect sensor IC provides
a 12-bit digital value corresponding to the magnetic field
measured in each of the X, Y, and Z axes. The ALS31300 is
preconfigured for use in 3D sensing applications for head-on
linear motion, slide-by position sensing, and rotation angle
measurements. The ALS31300 is also offered in joystick mode,
including a low gain option for the Z axis channel. This feature
enables the use of a back-bias magnet to provide return-to-zero
force instead of traditional spring-based solutions.
Continued on next page...
Power management of the ALS31300 is highly configurable,
allowing for system-level optimization of supply current and
performance. Sleep mode consumes just 14 nA (typical),
making the ALS31300 well suited for portable, battery-operated
applications.
PACKAGE: 10-Contact DFN (EJ)
Pin 1
Z
Y
Three different factory-programmed sensitivity ranges are
available: ±500 G, ±1000 G, and ±2000 G.
The I2C address of the ALS31300 can be set either by external
resistors (16 unique addresses) or programmed into EEPROM
via I2C (127 unique addresses), allowing for multiple devices
on the same bus. The ALS31300 also includes 78 bits of user
EEPROM.
The ALS31300 is supplied in a 3 mm × 3 mm × 0.8 mm,
10-contact DFN package (“EJ”). This small footprint package
is lead (Pb) free, with 100 % matte-tin leadframe plating.
X
Not to scale
Power
Controller
VCC
Z
Y
MUX
I2C Serial
Interface
Temp
Sensor
Digital
Controller
ADC
X
Slave
Address
ADC
SDA
SCL
ADR0
ADR1
INT
Hall
Elements
Charge
Pump
EEPROM
Memory
GND
Figure 1: Functional Block Diagram
ALS31300-DS, Rev. 9
MCO-0000228
June 12, 2020
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
FEATURES AND BENEFITS (continued)
• Flexible 12-bit ADC with 10-bit ENOB (Effective Number of Bits)
• 1% (typ) accurate factory-trimmed sensitivity options
(±500 G, ±1000 G, and ±2000 G full-scale input)
• Integrated temperature sensor
• Wide ambient temperature range: –40°C to 85°C
• 10-contact 3 mm × 3 mm × 0.8 mm DFN package for
implementation in low-profile, high-density PCB designs and
space-constrained applications
SELECTION GUIDE
Part Number
X/Y Channel Sensitivity
(LSB/G) [1]
Z Channel Sensitivity
(LSB/G) [1]
ALS31300EEJASR-500
4
4
ALS31300EEJASR-1000
2
2
ALS31300EEJASR-2000
1
1
ALS31300EEJASR-JOY [3]
1
0.25
Packing [2]
6000 pieces per 13-inch reel
1 gauss (G) = 0.1 millitesla (mT).
Contact Allegro™ for alternate packing options.
[3] Joystick devices have reduced gain on the Z axis to accommodate back bias magnets.
[1]
[2]
NAMING SPECIFICATION
ALS31300EEJASR-500
Factory Configuration: 500 = 500 gauss
Packing Option: SR = 6000 pieces per 13-inch reel
Package Type: EJA = 10-contact DFN
Operating Temperature Range (TA ): E = –40°C to 85°C
Allegro Linear Sensor 5-digit part number
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
2
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
Characteristic
Symbol
Notes
Rating
Unit
Forward Supply Voltage
VCC
5.5
V
Reverse Supply Voltage
VRCC
–0.1
V
V
All Other Pins Forward Voltage
VIN
5.5
All Other Pins Reverse Voltage
VR
–0.1
V
Operating Ambient Temperature
TA
–40 to 85
°C
Maximum Junction Temperature
TJ(MAX)
165
°C
Tstg
–65 to 170
°C
1000
writes
Storage Temperature [1]
EEPROM Write Count
[1]
Range E
–
Number of times EEPROM can be written
Stresses beyond the Absolute Maximum Ratings may result in permanent device damage. Exposure to absolute maximum rating conditions for
extended periods of time may affect device reliability.
THERMAL CHARACTERISTICS [2]
Characteristic
Symbol
Package Thermal Resistance [3]
[2]
Test Conditions
Value
Unit
65
°C/W
Measured on 2-layer board with copper limited to the solder pads and
0.88 in.2 of copper on each side
RθJA
Thermal characteristics may require derating at maximum conditions. See application section for more information.
thermal information available on the Allegro website.
[3] Additional
VCC
10 kΩ
VCC
10 kΩ
SCL
Customer
Microcontroller
VCC
CBYPASS
0.1 µF
VCC
SDA
ADR0
ALS31300
10 kΩ
ADR1
GND
INT
Figure 2: Typical Application
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
3
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
PINOUT DIAGRAM AND TERMINAL LIST TABLE
VCC
1
10 NC
ADR0
2
9
NC
GND
3
8
SCL
INT
4
7
SDA
NC
5
6
ADR1
PAD
Package EJ, 10-Contact DFN Pinout Diagram
Terminal List Table
Number
Name
Function
1
VCC
Power supply input. Bypass VCC to GND with a 0.1 µF capacitor.
2
ADR0
I2C Address Select 0. Connect a resistive divider to ADR0 to
select the device address. See Application Information section on
addressing for more information.
3
GND
Ground signal terminal.
4
INT
Interrupt output. See Application Information section on interrupt
function for more information.
5, 9, 10
NC
Not internally connected. Connect to GND.
6
ADR1
7
SDA
I2C serial data input/output. Open-drain.
8
SCL
I2C serial clock input
–
PAD
Exposed pad. Not connected internally.
I2C Address Select 1. Connect a resistive divider to ADR1 to select
the device’s address. See Application Information section on
addressing for more information.
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
4
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
ELECTRICAL CHARACTERISTICS: Valid at TA = 25°C, VCC = 3.0 V, CBYPASS = 0.1 µF, unless otherwise specified
Characteristics
Symbol
Test Conditions
Min.
Typ. [1]
Max.
Unit
2.65
3.0
3.5
V
2.8
–
3.5
V
–
3.4
3.9
mA
ELECTRICAL CHARACTERISTICS
Supply Voltage
VCC
ICC(ACTIVE)
Normal operation
EEPROM
programming [2]
Sleep = 0, or active state when sleep = 2
ICC(INACTIVE) Sleep = 2; inactive state
Supply Current [3]
ICC(LPDCM)
ICC(SLEEP)
ICC(EE)
–
12
–
µA
Average current in LPDCM; Sleep = 2,
LPM_CNT_MAX = 7, BW Select = 6
–
12
–
µA
Average current in LPDCM; Sleep = 2,
LPP_CNT_MAX = 0, BW Select = 0
–
2
–
mA
VCC = 3.0 V, Sleep mode = 1
–
14
100
nA
VCC = VCC(MAX), EEPROM programming
occurring [2]
–
6.2
6.7
mA
Power-On Delay Time [4]
tPOD
TA = 25°C, after VCC reaches VCC(MIN),
BW Select = 0
–
600
–
µs
EEPROM Write Delay Time
tEEP
Wait after writing to EEPROM
–
50
–
ms
ELIN
Through full range of BIN
–
±1.7
–
%
NdFeB magnet
–
0.12
–
% / °C
–
90
–
Ω
VIN = 0 V to VCC
–1
0
1
µA
Linearity Sensitivity Error
Sensitivity Temperature Coefficient [5]
TCSENS
INT PIN CHARACTERISTICS
INT Output On Resistance
INT Input Current
RON
IINT(IN)
INT Pull Up Resistance
RINT(PU)
2.4
10
–
kΩ
INT Pull Up Voltage
VINT(PU)
–
3.0
3.5
V
ADDRESS PIN CHARACTERISTICS
[5]
Address Value 0 Reference
VADDR0
ADR0, ADR1
–
0
0.1
× VCC
Address Value 1 Reference
VADDR1
ADR0, ADR1
0.23
0.33
0.43
× VCC
Address Value 2 Reference
VADDR2
ADR0, ADR1
0.57
0.67
0.77
× VCC
Address Value 3 Reference
VADDR3
ADR0, ADR1
0.9
1
–
× VCC
Address Pin Input Resistance
RADD(IN)
ADR0, ADR1
0.8
1
1.2
MΩ
Typical values with ± are mean ±3 sigma.
Parameter is tested at wafer probe only.
[3] I
CC will vary based on lower power duty cycle settings. See Application Information section on power modes.
[4] The device will not respond to I2C inputs until after the power-on delay time. t
POD will vary based on BW Select code, with code 0 being the slowest.
[5] Based on characterization data and guaranteed by design. Not verified at final test.
[1]
[2]
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
5
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
I2C INTERFACE CHARACTERISTICS [1]: Valid at TA = 25°C, CBYPASS = 0.1 µF, RPU = 10 kΩ, and I2C Clock Speed (FCLK) =
400 kHz, unless otherwise specified
Characteristics
Symbol
Min.
Typ. [1]
Max.
Unit
tBF
1.3
–
–
µs
Hold Time Start Condition
tSTA(H)
0.6
–
–
µs
Setup Time for Repeated Start Condition
tSTA(S)
0.6
–
–
µs
SCL Low Time
tLOW
1.3
–
–
µs
SCL High Time
tHIGH
0.6
–
–
µs
Data Setup Time
tDAT(S)
100
–
–
ns
Data Hold Time
tDAT(H)
0
–
900
ns
Setup Time for Stop Condition
tSTO(S)
0.6
–
–
µs
–
–
0.9
V
Bus Free Time Between Stop and Start
Logic Input Low Level (SDA, SCL Pins)
I2C threshold = 0; 3.0 V Compatible Mode
VI(L)
Logic Input High Level (SDA, SCL Pins)
Test Conditions
I2C
VI(H)
–
–
0.54
V
I2C threshold = 0; 3.0 V Compatible Mode
threshold = 1; 1.8 V Compatible Mode
2.1
–
–
V
I2C threshold = 1; 1.8 V Compatible Mode
1.26
–
–
V
Logic Input Current
II2C(IN)
VIN = 0 V to VCC, RPU = 2.4 kΩ
–1
0
1
µA
Output Voltage (SDA Pin)
VO(L)
ILOAD = 1.5 mA
–
–
0.36
V
Clock Frequency (SCL Pin)
fCLK
–
400
1000
kHz
Output Fall Time (SDA Pin)
tf
–
–
250
ns
I2C
Pull-Up Resistance
I2C Pull-Up Voltage
Total Capacitive Load for SDL and SDA
Buses
[1] I2C
RPU = 2.4 kΩ, CBUS = 100 pF
RI2C(PU)
2.4
10
–
kΩ
VI2C(PU)
1.8
3.0
3.3
V
CBUS
–
–
100
pF
Interface Characteristics are guaranteed by design and are not factory tested.
tSTA(S) tSTA(H)
tDAT(S)
tDAT(H)
tSTO(S)
tBF
SDA
SCL
tLOW
tHIGH
Figure 3: I2C Interface Timing Diagram
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
6
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
ALS31300EEJASR-500 PERFORMANCE CHARACTERISTICS: Valid at TA = 25°C, VCC = 3.0 V, and CBYPASS = 0.1 µF,
unless otherwise specified
Characteristics
Symbol
Test Conditions
Min.
Typ. [1]
Max.
Unit
NOMINAL PERFORMANCE
Optimized Sensing Range
BIN
–500
–
500
G
Sensitivity
SENS
–
4
–
LSB/G
Zero-Field Offset Code
QVO
BIN = 0 G
–
0
–
LSB
Offset Error X/Y Axes
EOFF(XY)
BIN = 0 G
–24
±13.4
24
LSB
Offset Error Z Axis
EOFF(Z)
BIN = 0 G
–24
±11.8
24
LSB
ACCURACY PERFORMANCE
Sensitivity Error X/Y Axes
ESENS(XY)
BIN = BIN(MAX)
–2.5
±0.7
2.5
%
Sensitivity Error Z Axis
ESENS(Z)
BIN = BIN(MAX)
–4.5
±0.6
4.5
%
Sensitivity Mismatch Error
X Axis to Y Axis
EMATCH(XY)
BIN = BIN(MAX)
–
±1.3
–
%
Sensitivity Mismatch Error
X/Y Axes to Z Axis
EMATCH(XYZ)
BIN = BIN(MAX)
–
±1.3
–
%
RMS Noise X/Y Channels [2]
NRMS(XY)
BW Select = 0
–
4
–
LSB
RMS Noise Z Channel
NRMS(Z)
BW Select = 0
–
1.5
–
LSB
[2]
LIFETIME DRIFT CHARACTERISTICS
Offset Error Lifetime Drift
EOFF_DRIFT
–10
–
10
LSB
Sensitivity Error Lifetime Drift
ESENS_DRIFT
–2.6
–
2.6
%
[1]
[2]
Typical values with ± are 3 sigma values.
RMS noise equivalent to 1 sigma distribution.
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
7
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
ALS31300EEJASR-1000 PERFORMANCE CHARACTERISTICS: Valid at TA = 25°C, VCC = 3.0 V, and CBYPASS = 0.1 µF,
unless otherwise specified
Characteristics
Symbol
Test Conditions
Min.
Typ. [1]
Max.
Unit
NOMINAL PERFORMANCE
Optimized Sensing Range
BIN
–1000
–
1000
G
Sensitivity
SENS
–
2
–
LSB/G
Zero-Field Offset Code
QVO
BIN = 0 G
–
0
–
LSB
Offset Error X/Y Axes
EOFF(XY)
BIN = 0 G
–12
–
12
LSB
Offset Error Z Axis
EOFF(Z)
BIN = 0 G
–12
–
12
LSB
ACCURACY PERFORMANCE
Sensitivity Error X/Y Axes
ESENS(XY)
BIN = BIN(MAX)
–2.5
±0.7
2.5
%
Sensitivity Error Z Axis
ESENS(Z)
BIN = BIN(MAX)
–4.5
±0.6
4.5
%
Sensitivity Mismatch Error
X Axis to Y Axis
EMATCH(XY)
BIN = BIN(MAX)
–
±1.3
–
%
Sensitivity Mismatch Error
X/Y Axes to Z Axis
EMATCH(XYZ)
BIN = BIN(MAX)
–
±1.3
–
%
RMS Noise X/Y Channels [2]
NRMS(XY)
BW Select = 0
–
2
–
LSB
RMS Noise Z Channel
NRMS(Z)
BW Select = 0
–
1.5
–
LSB
[2]
LIFETIME DRIFT CHARACTERISTICS
Offset Error Lifetime Drift
EOFF_DRIFT
–10
–
10
LSB
Sensitivity Error Lifetime Drift
ESENS_DRIFT
–2.6
–
2.6
%
[1]
[2]
Typical values with ± are 3 sigma values.
RMS noise equivalent to 1 sigma distribution.
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
8
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
ALS31300EEJASR-2000 PERFORMANCE CHARACTERISTICS: Valid at TA = 25°C, VCC = 3.0 V, and CBYPASS = 0.1 µF,
unless otherwise specified
Characteristics
Symbol
Test Conditions
Min.
Typ. [1]
Max.
Unit
NOMINAL PERFORMANCE
Optimized Sensing Range
BIN
–2000
–
2000
G
Sensitivity
SENS
–
1
–
LSB/G
Zero-Field Offset Code
QVO
BIN = 0 G
–
0
–
LSB
Offset Error X/Y Axes
EOFF(XY)
BIN = 0 G
–12
–
12
LSB
Offset Error Z Axis
EOFF(Z)
BIN = 0 G
–12
–
12
LSB
ACCURACY PERFORMANCE
Sensitivity Error X/Y Axes
ESENS(XY)
BIN = BIN(MAX)
–2.5
±0.7
2.5
%
Sensitivity Error Z Axis
ESENS(Z)
BIN = BIN(MAX)
–4.5
±0.6
4.5
%
Sensitivity Mismatch Error
X Axis to Y Axis
EMATCH(XY)
BIN = BIN(MAX)
–
±1.3
–
%
Sensitivity Mismatch Error
X/Y Axes to Z Axis
EMATCH(XYZ)
BIN = BIN(MAX)
–
±1.3
–
%
RMS Noise X/Y Channels [2]
NRMS(XY)
BW Select = 0
–
1.5
–
LSB
RMS Noise Z Channel
NRMS(Z)
BW Select = 0
–
1.5
–
LSB
[2]
LIFETIME DRIFT CHARACTERISTICS
Offset Error Lifetime Drift
EOFF_DRIFT
–10
–
10
LSB
Sensitivity Error Lifetime Drift
ESENS_DRIFT
–2.6
–
2.6
%
[1]
[2]
Typical values with ± are 3 sigma values.
RMS noise equivalent to 1 sigma distribution.
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
9
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
ALS31300EEJASR-JOY PERFORMANCE CHARACTERISTICS: Valid at TA = 25°C, VCC = 3.0 V, and CBYPASS = 0.1 µF,
unless otherwise specified
Characteristics
Symbol
Test Conditions
Min.
Typ. [1]
Max.
Unit
X and Y axes
–2000
–
2000
G
Z axis
–8000
–
8000
NOMINAL PERFORMANCE
Optimized Sensing Range
BIN
X and Y axes
–
1
–
Z axis
–
0.25
–
QVO
BIN = 0 G
–
0
–
LSB
Offset Error X/Y Axes
EOFF(XY)
BIN = 0 G
–12
±13.4
12
LSB
Offset Error Z Axis
EOFF(Z)
BIN = 0 G
–12
±11.8
12
LSB
Sensitivity
SENS
Zero-Field Offset Code
LSB/G
ACCURACY PERFORMANCE
Sensitivity Error X/Y Axes
ESENS(XY)
BIN = BIN(MAX)
–2.5
±0.7
2.5
%
Sensitivity Error Z Axis
ESENS(Z)
BIN = BIN(MAX)
–4.5
±0.6
4.5
%
EMATCH(XY)
BIN = BIN(MAX)
–
±1.3
–
%
RMS Noise X/Y Channels [2]
NRMS(XY)
BW Select = 0
–
1.5
–
LSB
RMS Noise Z Channel
NRMS(Z)
BW Select = 0
–
1.5
–
LSB
Sensitivity Mismatch Error
X Axis to Y Axis
[2]
LIFETIME DRIFT CHARACTERISTICS
Offset Error Lifetime Drift
EOFF_DRIFT
–10
–
10
LSB
Sensitivity Error Lifetime Drift
ESENS_DRIFT
–2.6
–
2.6
%
[1]
[2]
Typical values with ± are 3 sigma values.
RMS noise equivalent to 1 sigma distribution.
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
10
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
MEMORY MAP
The memory map below lists the locations of accessible registers on the ALS31300. See the following sections on EEPROM and Primary
Registers for detailed information.
Reserved
Read Only
Read/Write Volatile
Read/Write EEPROM
Read/Write 1 to Clear
Clear on Read
0x0F
RESERVED
Customer EEPROM
0
1
5
INT Latch Enable
2
6
Channel X Enable
3
7
Channel Y Enable
INT
Temperature
MSBs
4
Temperature
LSBs
5
6
Hall Status
New Data
8
9
11
Z_Axis_LSBs
10
12
13
14
15
16
17
Y_Axis_LSBs
7
Z_Axis_MSBs
X_Axis_LSBs
18
21
22
23
24
25
26
27
28
29
30
31
RESERVED
19
0x29
Y_Axis_MSBs
INT Write
X_Axis_MSBs
20
0x28
4
8
Channel Z Enable
Low
Power
Counter
RESERVED
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955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
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0
Customer EEPROM
Sleep
Customer EEPROM
RESERVED
1
RESERVED
0x0E
2
0x0D
X INT
Threshold
I2C
Loop Mode
RESERVED
Address
9
Y INT
Threshold
0x03
0x27
Customer EE
3
Z INT
Threshold
I2C Threshold
11
10
12
13
14
15
17
Disable Slave ADC
16
18
I2C CRC Enable
19
Y INT Enable
Slave Address
X INT Enable
Hall Mode
Z INT Enable
INT EEPROM Enable
INT Mode
Signed INT Enable
20
21
22
BW Select
23
24
25
26
27
28
RESERVED
INT EEPROM Status
0x02
29
30
Address
31
Table 1: Memory Map
11
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
EEPROM
The following EEPROM addresses are customer accessible and may be read at any time, with or without entering the customer access
code. Customer Access mode must be enabled to write to any of these registers.
Reserved
Read Only
Read/Write Volatile
Read/Write EEPROM
Write 1 to Clear
Clear on Read
Table 2: EEPROM 0x02
Address
Bits
Default
Name
31:24
0
Reserved
23:21
20:19
0x02
0
See
Selection
Guide
Description
Reserved
BW Select
Used to control the sample rate of the device. Resolution can be traded for
faster samples.
0 = Slowest sample rate, highest resolution
7 = Fastest sample rate, lowest resolution
See Bandwidth Selection section.
Hall Mode
Controls the operation mode of the Hall plates.
0 = Single-Ended Hall Mode
1 = Reserved
2 = Common Hall Mode
3 = Reserved
See Hall Modes section.
18
0
I2C CRC Enable
I2C Cyclic Redundancy Check (CRC) output byte enabled. Enable CRC for
applications that require high data integrity.
0 = Disabled
1 = Enabled
See CRC section
17
0
Disable Slave ADC
Disable the external slave address pins. When set, the EEPROM setting in
Slave Address is used to determine the slave address. See I2C Addressing
section.
16:10
0
Slave Address
Used to set the slave address for the device when either Disable Slave ADC is
set, or the voltages on the slave address pins are set to VCC.
See I2C Addressing section.
9
1
I2C Threshold
Enables 1.8 V or 3 V compatible I2C.
0 = 3 V compatible mode (Increases threshold for logic input high level)
1 = 1.8 V compatible mode
8
1
Channel Z Enable
Enables the Z channel. Disable for faster update rate if this axis is not needed.
7
1
Channel Y Enable
Enables the Y channel. Disable for faster update rate if this axis is not needed.
6
1
Channel X Enable
Enables the X channel. Disable for faster update rate if this axis is not needed.
Enables volatile latching of the INT signal. When set, if an interrupt event
occurs, the INT status bit and INT output will both remain latched even after the
event goes away.
See Interrupt section.
5
0
INT Latch Enable
4:0
0
Customer EEPROM
Customer non-volatile EEPROM. Can be used to store any customer
information. Does not affect device operation.
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12
ALS31300
Reserved
with
Read Only
Read/Write Volatile
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
Read/Write EEPROM
Write 1 to Clear
Clear on Read
Table 3: EEPROM 0x03
Address
Bits
Default
Name
31:25
0
Reserved
24
0
Signed INT Enable
Description
Reserved
Controls if the interrupt threshold(s) are absolute or signed.
In absolute mode, an interrupt is triggered if the applied field crosses the
threshold in either the positive or negative direction. In signed mode, an
interrupt is only triggered if the applied field passes the threshold in a single
direction specified by the user.
0 = Absolute
1 = Signed
See Interrupt section.
Controls the behavior of INT.
0 = Threshold Mode. Compares the sensor’s most recent measurement to the
specified event conditions.
1 = Delta Mode. Used in combination with LPDCM. Compares the sensor’s
most recent measurement to the first measurement when the device entered
LPDCM and the specified event conditions.
See Interrupt section.
23
0
INT Mode
22
0
INT EEPROM Status
Non-volatile EEPROM storage to indicate an interrupt event has occurred.
See Interrupt section.
21
0
INT EEPROM Enable
If set, INT EEPROM Status will be automatically written when an interrupt
event occurs.
See Interrupt section.
20
0
Z INT Enable
INT enable for Z axis. See Interrupt section.
19
0
Y INT Enable
INT enable for Y axis. See Interrupt section.
18
0
X INT Enable
INT enable for X axis. See Interrupt section.
17:12
0
Z INT Threshold
INT threshold for Z axis. Affected by Signed INT Enable. See Interrupt section.
11:6
0
Y INT Threshold
INT threshold for Y axis. Affected by Signed INT Enable. See Interrupt section.
5:0
0
X INT Threshold
INT threshold for X axis. Affected by Signed INT Enable. See Interrupt section.
0x03
Table 4: EEPROM 0x0D, 0x0E and 0x0F
Address
Bits
Default
Name
Description
0x0D
25:0
0
Customer EEPROM
Customer non-volatile EEPROM space. Can be used to store any customer
information. Does not affect device operation.
0x0E
25:0
0
Customer EEPROM
Customer non-volatile EEPROM space. Can be used to store any customer
information. Does not affect device operation.
0x0F
25:0
0
Customer EEPROM
Customer non-volatile EEPROM space. Can be used to store any customer
information. Does not affect device operation.
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13
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
PRIMARY REGISTERS
The following registers are customer accessible and may be read at any time, with or without entering the customer access code. Customer
Access mode must be enabled to write to any of these registers, with the exception of sleep, which can be written to regardless of access
mode.
Reserved
Read Only
Read/Write Volatile
Read/Write EEPROM
Write 1 to Clear
Clear on Read
Table 5: Volatile 0x27
Address
0x27
Bits
Name
Description
31:7
Reserved
6:4
Low-Power Mode
Count Max
Reserved
Sets max counter for inactive time during low-power duty cycle mode. ALS31300 offers 8 discrete
time frames for inactive time. See Application Information section on low-power modes.
3:2
I2C Loop-Mode
Sets I2C readback mode to single read, fast loop, or full loop mode. See Application Information
section on readback modes.
1:0
Sleep
Sets device operating mode to full active, ultralow power sleep mode, or low-power duty cycle
mode. See Application Information section on low-power modes.
Table 6: Volatile 0x28
Address
0x28
Bits
Name
Description
31:24
X Axis MSBs
MSBs of the register proportional to the field strength in the X direction.
23:16
Y Axis MSBs
MSBs of the register proportional to the field strength in the Y direction.
15:8
Z Axis MSBs
MSBs of the register proportional to the field strength in the Z direction.
7
New Data
6
Interrupt
5:0
Temperature MSBs
New data update flag for XYZ. Cleared when read. Set when a new update is available. Use this
bit when sampling the device faster than the update rate to avoid averaging the same sample
twice. This bit clears when address 0x28 is read.
Set when the interrupt thresholds are crossed. Latched if INT Latch Enable is set. In latched
mode, latch can be cleared by writing a 1 to this bit location.
MSBs of the temperature register proportional to the absolute temperature.
Table 7: Volatile 0x29
Address
0x29
Bits
Name
31:21
Reserved
20
Interrupt Write
19:16
X Axis LSBs
LSBs of the register proportional to the field-strength in the X direction.
15:12
Y Axis LSBs
LSBs of the register proportional to the field-strength in the Y direction.
11:8
Z Axis LSBs
LSBs of the register proportional to the field-strength in the Z direction.
7:6
Hall Mode Status
5:0
Temperature LSBs
Description
Reserved
Status bit to indicate if an interrupt write is in progress. Will be set if Interrupt EEPROM Enable
is set and an interrupt event has occurred. This field will be set while the device is writing the
Interrupt EEPROM Status bit in address 0x03. When the writing is complete, this bit will clear
automatically.
The Hall mode of the current readout. Will be primarily used if 0x02 Hall mode is set to
alternating mode. See Application Information section on Hall modes.
0 = Value measured in Single-Ended Hall Mode
1 = Reserved
2 = Value measured in Common Hall Mode
LSBs of the temperature register proportional to the absolute temperature.
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14
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
APPLICATION INFORMATION
Magnetic Sensor(s) Output
Power Modes
The ALS31300 provides a 12-bit digital output value that is proportional to the magnetic field applied normally to any of the Hall
elements. The most and least significant bits for X, Y, and Z channels are separated across two primary registers: 0x28 and 0x29.
Power management on the ALS31300 is user-selectable and
highly configurable, allowing for system-level optimization of
current consumption and performance. The ALS31300 supports
three different power modes: Active Mode, Sleep Mode, and
Low-Power Duty Cycle Mode (LPDCM). The operating mode of
the ALS31300 will be determined by the value in Sleep, Address
0x27, bits 1:0, described in Table 9.
The process begins with a full 8-byte read of MSB and LSB registers to construct a 12-bit 2’s complement signed value. All data
must be read in a single 8-byte read when combining registers
or the result will be the combination of two separate samples in
time. The 12 bits of data are combined per Table 8.
Table 9: Sleep
Address
Table 8: Combined MSBs and LSBs for Magnetic Data
11
10
9
DATA
8
7
6
5
4
3
MSB Data
2
1
MSB = 1100_0000
LSB = 0110
The combined data {MSB;LSB} = 1100_0000_0110, or the
decimal equivalent = –1018. This value can then be converted to
gauss by dividing by the sensitivity of the ALS31300.
An ALS31300 with 500 gauss full-scale input range will have a
typical sensitivity of 4 LSB/gauss. The 12-bit magnetic data value
can be converted to gauss using the equation:
gauss = –1018 LSB ÷ 4 LSB ⁄ G = –254 gauss
Example source code for combining MSB and LSB data is available in the 3D Linear and 2D Angle Sensing Application Note.
Temperature Sensor Output
The ALS31300 provides a 12-bit digital output that is proportional to the junction temperature of the IC. Similar to magnetic
data, the most and least significant bits for temperature are separated across two primary registers: 0x28 and 0x29. Temperature
is a 12-bit coded value. Temperature can be calculated by:
302(
1:0
LSB Data
Assume that a full 8-byte read returns the following binary data
for a single axis:
(° ) =
0x27
0
− 1708)
4096
After power-on, the temperature sensor is stable within 8 ms and it
is updated every 8 ms after that. In low-power duty cycle mode, the
temperature sensor is updated once every 10 low power cycles.
Value
Operating Mode
0
Active Mode
1
Sleep Mode
2
Low-Power Duty Cycle Mode
SLEEP MODE
In Sleep Mode, the ALS31300 enters a near powered-off state
where it consumes the minimum amount of current (14 nA typical).
In this mode, the device will still respond to I2C commands, but
will not update magnetic or temperature data. Sleep mode is valuable in applications where the supply voltage cannot be disabled
but minimal power consumption is required. The time it takes to
exit sleep mode is equivalent to Power-On Delay Time (tPOD).
LOW-POWER DUTY CYCLE MODE (LPDCM)
In Low-Power Duty Cycle Mode (LPDCM), the ALS31300
toggles between Active and Inactive states, reducing overall current
consumption. The average ICC for the ALS31300 during LowPower Duty Cycle Mode will vary based on the settings used and
may range anywhere from 2 mA to 12 µA (typical). The diagram in
Figure 4 shows the profile of ICC as the ALS31300 toggles between
Active and Inactive states during Low-Power Duty Cycle Mode.
4
tACTIVE
ALS31300 Low-Power Duty Cycle Mode
3.5
ICC
VCC
3
VCC / ICC
BIT
Bits
2.5
2
1.5
tINACTIVE
1
0.5
ICC(INACTIVE)
0
ICC (mA)
Time
VCC (V)
Figure 4: ICC in Low-Power Duty Cycle Mode
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15
ALS31300
with
The inactive time will be determined by the value set in LowPower Mode Count Max, Address 0x27, bits 6:4. The ALS31300
offers eight discrete time frames, explained in Table 10. Typical
ICC consumed in the inactive state is 12 µA.
Table 10: LPDCM Inactive Time (tINACTIVE)
Address
0x27
Bits
6:4
Value
tINACTIVE (typ) (ms)
0
0.5
1
1
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
Update rate (typical) versus BW Select and active channels is
shown in Table 12. While the ALS31300 does update at high
bandwidths internally, throughput may be limited by the I2C
bus clocking frequency at the application level. This concept is
explained in the “Calculation Timing” section of the 3D Linear
and 2D Angle Sensing application note.
Table 12: Bandwidth Select and Update Rate
BW
Select
Value
2
5
3
10
4
50
5
100
6
500
7
1000
The active time will be determined by a combination of the
value in BW Select and the number of magnetic sensing channels enabled. For more information on LPDCM configuration,
refer to the Low-Power Management Application Note for the
ALS31300.
Bandwidth Selection
BW Select, address 0x02, bits 23:21, controls filtering modes on
the ALS31300 for the X, Y, and Z magnetic channels. This setting
will impact the resolution of sampled magnetic data, the device’s
update rate, and the overall bandwidth.
A lower value for BW Select offers increased measurement
resolution with a longer measurement duration. A higher value
for BW Select offers faster measurement time at the expense of
reduced resolution. This setting is valuable for controlling active
time during low-power duty cycle mode or increasing response
time. Typical noise versus BW Select are listed in Table 11.
Table 11: Bandwidth Select, Filtering Modes,
and Input Referred Noise
BW Select
Value
FIR Enabled
Z Channel
Noise (G)
X/Y Channel
Noise (G)
0
1
1.5
4
1
1
2
5
2
1
2.2
7
3
–
–
–
4
0
2
6
5
0
2.5
8
6
0
3.5
10
7
–
–
–
1 Channel
Update Rate
µs
2 Channel
Update Rate
3 Channel
Update Rate
–3 dB
Bandwidth
kHz
µs
kHz
µs
kHz
kHz
0
160
6
330
3
495
2
3.5
1
80
13
170
6
255
4
7
2
40
25
90
11
135
7
14
3
–
–
–
–
–
–
–
4
64
16
138
7
207
5
10
5
32
31
74
14
111
9
20
6
16
63
42
24
63
16
40
7
–
–
–
–
–
–
–
Magnetic sensing channels on the ALS31300 may be enabled
independently with channel x en, channel y en, and channel z en
bits, listed in Table 13.
Table 13: Channel Enable Control
Address
0x02
Bits
Value
Description
8
1
Enables Z sensing Channel
7
1
Enables Y Sensing Channel
6
1
Enables X Sensing Channel
Hall Modes
The ALS31300 offers two schemes to retrieve magnetic data from
the magnetic sensing elements. These settings are controlled via
Hall Mode, address 0x02, bits 20:19, described in Table 14.
Table 14: Hall Modes
Value
Mode
0
Single Ended
1
Reserved
2
Common Mode
Description
Reports magnetic data from Xi, Yi, and Zi
sensing elements.
Reserved
Reports magnetic data from XOE + XOW,
YON +YOS, and Zi sensing elements.
It is not advised to switch a factory-trimmed, single-ended device
(0) into common mode (2) or vice versa. Doing so may result in
sensor performance that is outside of the datasheet specifications.
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16
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
SINGLE-ENDED HALL MODE
Interrupt Modes
Magnetic data in registers 0x28 and 0x29 will be proportional to the
magnetic field seen by the inner sensing elements Xi, Yi, and Zi.
The ALS31300 includes two different interrupt modes, where
the user may select a threshold value or a maximum change in
field to compare. This setting is controlled via INT Mode, address
0x03, bit 23, explained in Table 15.
COMMON HALL MODE
Magnetic data in registers 0x28 and 0x29 will be proportional to
the sum of the fields as seen by the outer sensing elements of the
X and Y axes.
Concatenated X axis data {x_axis_MSB:x_axis_LSB} will be the
result of XO(EAST) + XO(WEST) sensing elements, while concatenated Y axis data {y_axis_MSB:y_axis_LSB} will be the result
of YO(NORTH) + YO(SOUTH) sensing elements.
Z axis data will be the same as in single-ended mode.
Table 15: INT Modes
INT Mode
Value
Mode
Description
0
Threshold
Mode
An interrupt event occurs when the magnetic
ADC Output data ≥ threshold.
1
Delta
Mode
Recent magnetic data is compared to stored
value when entering LPDCM. An interrupt event
occurs when the change in magnetic ADC
Output data ≥ user-programmed delta value.
Interrupt
THRESHOLD MODE
The Interrupt feature on the ALS31300 integrates detection and
reporting of large changes in applied magnetic field. An interrupt
event is initiated when the applied magnetic field forces the ADC
output to a value greater than or equal to the user-programmed
threshold. Interrupt detection may be independently enabled or
disabled for each of the three axes.
In Threshold Interrupt Mode, the most recent magnetic sample
data is compared to the user-selected threshold for each channel.
If the magnetic ADC value is greater than or equal to this threshold, an interrupt event will occur.
Interrupt Reporting
Delta Interrupt Mode is used in combination with Low-Power
Duty Cycle Mode, where the ALS31300 toggles between an
Active and a Sleep state. In Delta Interrupt Mode, the ALS31300
will remember its last magnetic data sample when entering
LPDCM.
The ALS31300 will report the presence of an interrupt event by
asserting the INT pin and the INT bit in register 0x28 will be set.
Interrupt reporting may be latched or unlatched depending on the
value of INT Latch Enable, address 0x02, bit 5.
DELTA MODE
In a latched state, the INT pin will assert when an event is
detected, and the INT bit will be set. Should the event subside,
the INT pin and INT bit will remain set.
New magnetic data is compared to the original sample every time
the ALS31300 toggles into the active state. If the delta (change)
in magnetic data is larger than the user-selected delta, an interrupt
event will occur.
In an unlatched state, the INT pin will assert when an event is
detected, and the INT bit will be set. Should the event subside,
the ALS31300 will reset the INT pin and the INT bit will be
cleared.
User-selectable values for threshold and delta share the registers
Z INT Threshold, Y INT Threshold, and X INT Threshold, address
0x03, bits 17:0.
The ALS31300 may also report an interrupt event in EEPROM.
This is feature enabled by setting INT EEPROM Enable, address
0x03, bit 21. If an interrupt event is detected, the device will
write to INT EEPROM Status, address 0x03, bit 22.
In Threshold Mode, the value in these registers will be considered
a threshold, while in Delta Mode, the value in these registers will
be considered a delta. The ALS31300 may interpret these values
as signed or unsigned based on the Signed INT Enable bit.
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17
ALS31300
with
SIGNED INTERRUPT THRESHOLD
By default, the value for Signed INT Enable is set to 0, and the
user-programmed value for threshold is unsigned. This will
trigger an interrupt event when applying a positive or negative
magnetic field, causing the absolute value of the magnetic data to
meet or exceed the user-selected threshold.
If Signed INT Enable is set to 1, the value for threshold becomes
signed. This may be used to trigger interrupts on only positive or
only negative magnetic fields that cause the value of the magnetic
data to meet or exceed the user-programmed threshold.
Interrupt threshold for each channel can be programmed independently using registers Z INT Threshold, Y INT Threshold, and X
INT Threshold, address 0x03, bits 17:0. The following examples
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
set an interrupt threshold for the X axis, but the technique also
applies to Y and Z axes.
When Signed INT Enable = 0, the interrupt threshold will be
determined by the equation:
threshold = (INT Threshold + 1) × 25 – 1
When Signed INT Enable = 1, the interrupt threshold will be
determined by the equation:
if X INT Threshold ≥ 0
threshold = (INT Threshold + 1) × 26 – 1
if X INT Threshold < 0
threshold = (INT Threshold + 1) × 26
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18
ALS31300
I2C
with
I2C Interface
When a data write is requested by the Master, the ALS31300
pulls SDA low during the clock cycle following the data byte to
indicate that the data has been successfully received.
1. Serial Clock Line (SCL) output by the Master.
2. Serial Data Line (SDA) output by either the Master or the Slave.
The ALS31300 may only operate as a Slave device. Therefore, it
cannot initiate any transactions on the I2C bus.
After sending either an address byte or a data byte, the Master
must release the SDA line before the ninth clock cycle, allowing
the handshake process to occur.
Data Transmission and Timing Considerations
I2C Write Cycle Overview
I2C communication is composed of several steps outlined in the
following sequence.
The write cycle to access registers on the ALS31300 are outlined
in the sequence below.
1. Start Condition: Defined by a negative edge of the SDA line,
initiated by the Master, while SCL is high.
2. Address Cycle: 7-bit Slave address, plus 1 bit to indicate
write (0) or read (1), followed by an Acknowledge bit.
3. Data Cycles: Reading or writing 8 bits of data, followed by
an Acknowledge bit. This cycle can be repeated for multiple
bytes of data transfer. The first data byte on a write could be
the register address. See the following sections for further
information.
4. Stop Condition: Defined by a positive edge on the SDA line,
while SCL is high.
Except to indicate Start or Stop conditions, SDA must remain
stable while the clock signal is high. SDA may only change states
while SCL is low. It is acceptable for a Start or Stop condition to
occur at any time during the data transfer. The ALS31300 will
always respond to a Read or Write request by resetting the data
transfer sequence.
1. Master initiates Start Condition
2. Master sends 7-bit Slave address and the write bit (0)
3. Master waits for ACK from ALS31300
4. Master sends 8-bit register address
5. Master waits for ACK from ALS31300
6. Master sends 31:24 bits of data
7. Master waits for ACK from ALS31300
8. Master sends 23:16 bits of data
9. Master waits for ACK from ALS31300
10. Master sends 15:8 bits of data
11. Master waits for ACK from ALS31300
12. Master sends 7:0 bits of data
13. Master waits for ACK from ALS31300
14. Master initiates Stop Condition
The I2C write sequence is further illustrated in the timing diagrams below in Figure 5.
The state of the Read/Write bit is set to 0 to indicate a write cycle
and set to 1 to indicate a read cycle.
Device (Slave) Acknowledge
Start
Slave Address
1
2
3
4
5
6
7
8
Device (Slave) Acknowledge
… SCL
Device (Slave) Acknowledge
Write bit
Device (Slave) Acknowledge
Register Address
Register Data0
D6 D5 D4 D3 D2 D1 D0 W AK D7 D6 D5 D4 D3 D2 D1 D0 AK D7 D6 D5 D4 D3 D2 D1 D0 AK
SCL
… SDA
Output and Advanced Low Power Management
The Master monitors for an Acknowledge bit to confirm the
Slave device (ALS31300) is responding to the address byte.
When the ALS31300 decodes the 7-bit Slave address as valid, it
responds by pulling SDA low during the ninth clock cycle.
I2C is a synchronous, 2-wire serial communication protocol
which provides a full-duplex interface between two or more
devices. The bus specifics two logic signals:
SDA
3-D Linear Hall-Effect Sensor
9
1
2
3
4
5
6
7
8
Device (Slave) Acknowledge
9
1
2
3
4
5
6
7
8
Device (Slave) Acknowledge
Register Data2
Register Data3
Register Data1
D7 D6 D5 D4 D3 D2 D1 D0 AK D7 D6 D5 D4 D3 D2 D1 D0 AK D7 D6 D5 D4 D3 D2 D1 D0 AK
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
9
1
2
3
4
5
6
7
8
Stop
9
Figure 5: I2C Write Timing Diagram
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19
ALS31300
with
Customer Write Access
The timing diagram in Figure 6 shows the entire contents
(bits 31:0) of a single register location being transmitted. Optionally, the I2C Master may choose to replace the NACK with an
ACK instead, which allows the read sequence to continue. This
case will result in the transfer of contents (bits 31:24) from the
following register, address + 1. The master can then continue
acknowledging, issue the not-acknowledge (NACK), or stop after
any byte to stop receiving data.
To enter customer access mode, an access command must be
sent via the I2C interface. The command consists of a serial write
operation with the address and data values shown in Table 16.
Once the customer access mode is entered, it is not possible to
change access modes without power-cycling the device. After
power up, there is no time limit to when the access code may be
entered.
Note that only the initial register address is required for reads,
allowing for faster data retrieval. However, this restricts data
retrieval to sequential registers when using a single read command. When the Master provides a non-acknowledge bit and stop
bit, the ALS31300 stops sending data. If nonsequential registers
are to be read, separate read commands must be sent.
Table 16: Customer Access Code
Access Mode
Address
Data
0x35
0x2C413534
Output and Advanced Low Power Management
The I2C read sequence is further illustrated in the timing diagrams in Figure 6.
An access code must be sent to the device prior to writing any of
the volatile registers or EEPROM in the ALS31300. If customer
access mode is not enabled, then no writes to the device are
allowed. The only exception to this rule is the sleep register,
which can be written regardless of the access mode. Furthermore,
any register or EEPROM location can be read at any time regardless of the access mode.
Customer Access
3-D Linear Hall-Effect Sensor
I2C
Read Cycle Overview
The read cycle to access registers on ALS31300 is outlined in the
sequence below.
1. Master initiates Start Condition
2. Master sends 7-bit Slave address
and the write bit (0)
3. Master waits for ACK from ALS31300
4. Master sends 8-bit register address
5. Master waits for ACK from ALS31300
6. Initiate a Start Condition; this time it is
referred to as a Restart Condition
7. Master sends 7-bit Slave address
and the read bit (1)
8. Master waits for ACK from ALS31300
9. Master receives 31:24 bits of data
10. Master sends ACK to ALS31300
11. Master receives 23:16 bits of data
12. Master sends ACK to ALS31300
13. Master receives 15:8 bits of data
14. Master sends ACK to ALS31300
15. Master receives 7:0 bits of data
16. Master sends NACK to ALS31300
17. Master initiates Stop Condition
Master Restart
Device (Slave) Acknowledge
Device (Slave) Acknowledge
Start
Write bit
Slave Address
Register Address
D7 D6 D5 D4 D3 D2 D1 D0 AK D7 D6 D5 D4 D3 D2 D1 D0 AK
SDA
1
SCL
2
3
4
5
6
7
8
9
1
2
1
2
3
4
5
6
Device (Slave) Acknowledge
7
6
7
8
9
1
Register Data
8
9
1
2
3
4
5
6
7
8
9
Master Non-Acknowledge
Device (Slave) Acknowledge
Register Data1
SCL
5
D7 D6 D5 D4 D3 D2 D1 D0 AK D7 D6 D5 D4 D3 D2 D1 D0 AK
… SCL
SDA
4
Device (Slave) Acknowledge
Device (Slave) Acknowledge
Read bit
Slave Address
… SDA
3
Register Data3
Register Data2
D7 D6 D5 D4 D3 D2 D1 D0 AK D7 D6 D5 D4 D3 D2 D1 D0 AK D7 D6 D5 D4 D3 D2 D1 D0
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
NAK
9
Figure 6: I2C Read Timing Diagram
Allegro MicroSystems
955 Perimeter Road
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www.allegromicro.com
20
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
I2C CRC Byte
FAST LOOP MODE
The ALS31300 CRC feature is enabled by setting the I2C CRC
Enable bit, Address 0x02, bit 18. When enabled, the ALS31300
read transaction returns one extra byte corresponding the CRC
calculation of that read. The bytes of the I2C read sequence used
for CRC calculation are:
Fast Loop Mode offers continuous reading of X, Y, Z, and temperature values, but is limited to the upper 8 bits of X, Y, and Z, and
upper 6 bits of Temperature. This mode is intended to be a time
efficient way of reading data from the IC at the expense of truncating resolution. The flow chart in Figure 7 depicts Fast Loop Mode.
1. 8-Bit Register Address
2. The 7-Bit Slave Address + Read bit (1’b1)
3. The four Data Bytes (32 Bits, MSB first)
The code is 8 bits in length and will be generated using the
CRC8-ATM (0x83) polynomial:
p(x) = x8 + x2 + x + 1
Table 17: Example CRC Calculation Result
Slave Address
Register
Address
Data
CRC
0xC3
0x28
0x282A2C80
0xEC
0xC3
0x28
0x282A2C00
0x65
I2C Readback Modes
The ALS31300 supports three different readback modes over the
I2C interface, including single, fast loop, and full loop modes.
These modes simplify the process of repeatedly polling the
ALS31300 for magnetic X, Y, Z, and Temperature data.
Readback modes on the ALS31300 are described in Table 18. The
desired readback mode may be entered by setting the appropriate
bits for I2C Loop Mode, address 0x27, bits 3:2.
Figure 7: Fast Loop Mode
FULL LOOP MODE
Full Loop Mode provides continuous reads of X, Y, Z, and Temperature data with full 12-bit resolution. This is the recommended
mode for applications that require a higher data rate for X, Y, Z,
and Temperature with full resolution. The flow chart in Figure 8
depicts Full Loop Mode.
Table 18: ALS31300 Looping Read Modes
Code
(Binary)
Mode
‘00’
Single
‘01’
Fast Loop
X, Y, Z, and Temperature fields are looped.
8 MSBs for X, Y, and Z, 6 MSBs for
Temperature are looped.
‘10’
Full Loop
X, Y, Z, and Temperature fields are looped.
Full 12-bit resolution fields are looped.
‘11’
Single
Description
No Looping. Similar to Default I2C.
Same as code 0.
SINGLE MODE
A single write or read command to any register—this is the
default mode and is best suited for setting fields and reading
static registers. If desired, this mode can be used to read X, Y, Z,
and Temperature data in a typical serial fashion, but fast or full
loop read modes are recommended for high-speed data retrieval.
Figure 8: Full Loop Mode
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
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21
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
I2C Addressing
Table 19 outlines the different addresses available to the ALS31300. In the special case where AD0 and AD1 are both tied to VCC,
the device will respond to the slave address stored in register 0x02 (bits 10:16). From the factory, this is set to 7b000000, with the bit
following the address indicating a read or write per the I2C specification. Note: Different values for the three MSBs of the address bits
(A6, A5, and A4) are available for factory programming if a conflict with other units occurs in the application design.
Table 19: I2C Slave Address Decoding
Voltage on AD1,
VA1 (× VCC)
0
0.33
0.67
1
Voltage on AD0,
VA0 (× VCC)
4-Bit Code from ADR1
and ADR0 Voltages
E3
E2
E1
E0
Slave Address Bits
A6
A5
A4
A3
A2
Slave Address
A1
A0
0
0
0
0
0
1
1
0
0
0
0
0
96
0.33
0
0
0
1
1
1
0
0
0
0
1
97
0.67
0
0
1
0
1
1
0
0
0
1
0
98
1
0
0
1
1
1
1
0
0
0
1
1
99
0
0
1
0
0
1
1
0
0
1
0
0
100
0.33
0
1
0
1
1
1
0
0
1
0
1
101
0.67
0
1
1
0
1
1
0
0
1
1
0
102
1
0
1
1
1
1
1
0
0
1
1
1
103
0
1
0
0
0
1
1
0
1
0
0
0
104
0.33
1
0
0
1
1
1
0
1
0
0
1
105
0.67
1
0
1
0
1
1
0
1
0
1
0
106
1
1
0
1
1
1
1
0
1
0
1
1
107
0
1
1
0
0
1
1
0
1
1
0
0
108
0.33
1
1
0
1
1
1
0
1
1
0
1
109
0.67
1
1
1
0
1
1
0
1
1
1
0
110
1
1
1
1
1
x
x
x
x
x
x
x
Set to 0 at the factory
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955 Perimeter Road
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www.allegromicro.com
22
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
SENSING ELEMENT LOCATIONS AND NORMALS
Dimensions in Millimeters – Not to Scale
The locations of the sensing elements are indicated in Figure 9. The outer elements for the X and Y axes are also referred to as north,
south, east, and west elements. For example, the right-most sensing element on the X axis is defined as XOE.
The normal faces of each element are indicated with an arrow.
1
10
YON
1.50
2
Xi
0.68
9
0.08
Z
3
X OW
0.68
4
5
X OE
Yi
8
0.13
0.68
0.68
7
YOS
6
1.50
Figure 9: ALS31300 Sensing Element Locations and Normals
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
23
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
PACKAGE OUTLINE DRAWING
For Reference Only – Not for Tooling Use
(Reference DWG 2860)
Dimensions in millimeters – NOT TO SCALE
Exact case and lead configuration at supplier discretion within limits shown
0.30
E
3.00 BSC
0.50
10
10
0.85
3.00 BSC
1.64 3.10
A
1
2
1
11X
D
0.08
0.75 ±0.05
C
0.25
+0.07
–0.05
SEATING
PLANE
C
PCB Layout Reference View
0.05
0.00
0.5 BSC
1
2.38
C
2
A Terminal #1 mark area
0.40 ±0.10
B Exposed thermal pad (reference only, terminal #1 identifier appearance at supplier discretion)
B
+0.10
1.65
–0.15
C Reference land pattern layout (reference IPC7351 SON50P300X300X80-11WEED3M);
all pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary to meet
application process requirements and PCB layout tolerances; when mounting on a
multilayer PCB, thermal vias at the exposed thermal pad land can improve thermal
dissipation (reference EIA/JEDEC Standard JESD51-5)
D Coplanarity includes exposed thermal pad and terminals
E Active Area Depth: 0.32 mm NOM
10
+0.10
2.38
–0.15
Figure 10: DFN10 (EJ) Package Drawing
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
24
ALS31300
with
I2C
3-D Linear Hall-Effect Sensor
Output and Advanced Low Power Management
Revision History
Number
Date
Description
–
June 21, 2017
Initial release
1
July 12, 2017
Updated Zero-Field Offset Code (pages 7-10)
2
January 26, 2018
3
April 26, 2018
4
May 2, 2018
5
August 22, 2018
Added Active Area Depth to Package Outline Drawing (page 24).
6
August 31, 2018
Updated EEPROM 0x02 (20:19, page 12), Volatile 0x29 (7:6, page 14), Hall Modes section (page 16);
removed Differential Hall Mode and Alternating Hall Mode sections (page 17).
7
March 12, 2019
Updated Temperature Sensor Output (page 15).
8
October 4, 2019
Updated RMS Noise Channel values (page 7-10), EEPROM 0x02 (16:10, page 12),
and I2C Addressing description (page 22).
9
June 12, 2020
Removed inapplicable EMATCH(XYZ) characteristic from ALS31300EEJASR-JOY performance
characteristics table (page 10)
Corrected address in Table 16 (page 20)
Editorial updates (page 1, 2, 12, 14, and 17)
Updated Table 19
Copyright 2020, Allegro MicroSystems.
Allegro MicroSystems 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 any devices or systems, including but not limited to life support devices or systems, in which a failure of
Allegro’s product can reasonably be expected to cause bodily harm.
The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems assumes no responsibility for its use; nor
for any infringement of patents or other rights of third parties which may result from its use.
Copies of this document are considered uncontrolled documents.
For the latest version of this document, visit our website:
www.allegromicro.com
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25
