A1340 [ALLEGRO]
High Precision Programmable Linear Hall Effect Sensor IC with EEPROM, Analog Output, and Advanced Output Linearization;型号: | A1340 |
厂家: | ALLEGRO MICROSYSTEMS |
描述: | High Precision Programmable Linear Hall Effect Sensor IC with EEPROM, Analog Output, and Advanced Output Linearization 可编程只读存储器 电动程控只读存储器 电可擦编程只读存储器 |
文件: | 总42页 (文件大小:2003K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
A1340
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
FEATURES AND BENEFITS
DESCRIPTION
•
•
•
Advanced 32-segment output linearization functionality
enables high output accuracy and linearity in the
presence of non-linear input magnetic fields
Customer adjustable sensitivity and offset, bandwidth,
output clamps, and 1st and 2nd order temperature
compensation
The A1340 device is a high precision, programmable Hall
effect linear sensor integrated circuit (IC) for both automotive
andnon-automotiveapplications.ThesignalpathoftheA1340
provides flexibility through external programming that allows
the generation of an accurate, and customized output voltage
from an input magnetic signal. The A1340 provides 12 bits of
output resolution,andsupportsamaximumbandwidthof3kHz.
Simultaneous programming of all parameters for accurate
and efficient system optimization
The BiCMOS, monolithic integrated circuit incorporates a
Hall sensor element, precision temperature-compensating
circuitrytoreducetheintrinsicsensitivityandoffsetdriftofthe
Hall element, a small-signal high-gain amplifier, proprietary
dynamic offset cancellation circuits, and advanced output
linearization circuitry.
• Factory trimmed magnetic input range (coarse sensitivity)
and signal offset
• Sensitivity temperature coefficient and magnetic offset drift
preset at Allegro, for maximum device accuracy without
requiring customer temperature testing
• Temperature-stable, mechanical stress immune, and
extremely low noise device output via proprietary
four-phase chopper stabilization and differential circuit
design techniques
• Diagnostics for open circuit and undervoltage
• Wide ambient temperature range: –40°C to 150°C
• Operates with 4.5 to 5.5 V supply voltage
With on-board EEPROM and advanced signal processing
functions, theA1340 provides an unmatched level of customer
reprogrammable options for characteristics such as gain and
offset, bandwidth, and output clamps. Multiple input magnetic
range and signal offset choices can be preset at the factory. In
addition, the device supports separate hot and cold, 1st and 2nd
order temperature compensation.
Package: 4-pin SIP (suffix KT)
A key feature of the A1340 is its ability to produce a highly
linear device output for nonlinear input magnetic fields.
To achieve this, the device divides the output into 32 equal
segments and applies a unique linearization coefficient factor
to each segment. Linearization coefficients are stored in a
look-up table in EEPROM.
1 mm case thickness
The A1340 sensor is available in a lead (Pb) free 4-pin single
in-line package (KT suffix), with 100% matte tin leadframe
plating.
Not to scale
Analog Subsystem
Digital Signal Processing
Output Stage
...00110011...
Magnetic
12-bit
Output
Voltage
12-bit
Signal
Factory Preset
Magnetic Range
and
Bandwidth
and
Temperature
Compensation
Sensitivity
and
Fine Offset
Adjustment
Hall
Element
A to D
Conversion
D to A
Conversion
Output
Driver
Clamps
Linearization
Signal Offset
Figure 1: A1340 Signal Processing Path.
Functions with programmable parameters indicated by double-headed arrows.
A1340-DS, Rev. 2
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
Selection Guide
Part Number
Packing*
A1340LKTTN-4-T
4000 pieces per 13-in. reel
*Contact Allegro™ for additional packing options
Table of Contents
Writing to Volatile Registers
20
20
20
21
22
23
24
24
25
25
26
27
Specifications
Absolute Maximum Ratings
Thermal Characteristics
3
3
3
Reading from EEPROM
Error Checking
Serial Interface Reference
Serial Interface Message Structure
Read
Functional Block Diagram
Pin-out Diagram and Terminal List
Electrical Characteristics
Magnetic Characteristics
Programmable Characteristics
Thermal Characteristics
Characteristic Performance
Functional Description
Signal Processing Parameter Setting
Digital Signal Processing
Bandwidth Selection
4
4
5
6
Read Acknowledge
Write
Write Access Code
Write Disable Code
7
10
11
14
14
14
14
14
16
16
16
17
18
18
18
19
19
19
19
Write Enable Code
EEPROM Structure
EEPROM Customer-Programmable Parameter
Reference
Definitions of Terms
Power-On Time, tPO
Respnse TIme, tRESP
Quiescent Voltage Output (QVO), VOUT(Q)
Sensitivity, Sens
29
37
37
37
37
37
Temperature Compensation
Digital Output Sensitivity (Gain) Adjustment
Output Fine Offset Adjustment
Linearization of Output
Output Polarity
Output Signal Clamps Setting
Protection Features
Magnetic Offset Drift Through Temperature Range 37
Sensitivity Drift Through Temperature Range
Sensitivity Drift Due to Package Hysteresis,
DSensPKG
Linearity Sensitivity Error
Ratiometric
38
Typical Application
38
38
38
40
Programming Serial Interface
Transaction Types
Writing the Access Code
Writing to Non-Volatile EEPROM
Package Outline Drawing
Allegro MicroSystems, LLC
115 Northeast Cutoff
2
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
SPECIFICATIONS
Absolute Maximum Ratings
Characteristic
Symbol
VCC
Notes
Rating
19
Unit
V
Forward Supply Voltage
Reverse Supply Voltage
VRCC
ICC
–20
30
V
Forward Supply Current
mA
mA
V
Reverse Supply Current
IRCC
–30
29
Forward Output Voltage (VOUT Pin)
Reverse Output Voltage (VOUT Pin)
Forward Output Sink Current (VOUT Pin)
VOUT
VROUT
ISINK
Maximum voltage depends on programmed voltage settings
–0.5
50
V
mA
Maximum Number of EEPROM Write
Cycles
EEPROMW(max)
100
cycle
Operating Ambient Temperature
Maximum Junction Temperature
Storage Temperature
TA
TJ(max)
Tstg
L temperature range
–40 to 150
165
ºC
ºC
ºC
–65 to 165
Thermal Characteristics may require derating at maximum conditions, see application information
Characteristic
Symbol
Test Conditions*
Value
Unit
Package Thermal Resistance
RθJA
1-layer PCB with copper limited to solder pads
174
ºC/W
*Additional thermal information available on the Allegro website.
Allegro MicroSystems, LLC
115 Northeast Cutoff
3
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
VCC
Analog
Regulator
Digital
Regulator
Serial
Decode
UVLO
POR
Factory Coarse Sensitivity
and Magnetic Range
Setting
Factory
Coarse Offset
Trim
Clock
Generator
EEPROM
HV Pulse
Analog
Front End
Digital
Subsystem
Serial
Interface
Master
Control
Pulse
Detect
EEPROM
Control
12
12
Bandwidth
Select
ADC
Scan/
IDDQ
Hall
Element
Anti-Alias
Filter
Linear-
ization
Temperature
Compensation
Digital Sensitivity
and Offset Trim
Temperature
Sensor
Clamp
Driver
GND
VOUT
DAC
ADC
A/D
Precision
Reference
Functional Block Diagram
Pin-out Diagram and Terminal List Table
Terminal List Table
Number
Name
Function
1
VCC
Input power supply, use bypass capacitor to connect to ground
Analog output pin; EEPROM strobe input
2
VOUT
3
4
NC
Not connected; connect to GND for optimal ESD performance
Device ground
GND
1
2 3 4
Package KT, 4-Pin SIP
Allegro MicroSystems, LLC
115 Northeast Cutoff
4
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
ELECTRICAL CHARACTERISTICS: valid through full operating temperature range, TA, and supply voltage, VCC
BYPASS = 10 nF, unless otherwise specified
,
C
Characteristics
Symbol
Test Conditions
Min.
Typ.
Max.
Unit1
General Electrical Characteristics
Supply Voltage
VCC
ICC
4.5
5
–
–
5.5
15
–
V
mA
V
Supply Current
Supply Zener Clamp Voltage
Hall Chopping Frequency4
VZSUPPLY TA = 25°C; ICC = ICC(max) + 3 mA
fC TA = 25°C
19
–
–
128
–
–
kHz
V
VCC(UV_low) TA = 25°C, UVLO falling
VCC(UV_high) TA = 25°C, UVLO rising
3.5
3.7
4.2
4.45
Undervoltage Lockout Threshold2
Output Electrical Characteristics
Output Saturation Voltage
–
V
VSAT(H)
VSAT(L)
ROUT = 10 kΩ to GND, VCC – VOUT,TA = 25°C
ROUT = 10 kΩ to VCC, TA = 25°C
–
–
0.2
0.2
35
0.3
0.3
42
–
V
V
ILIMIT(SNK) VOUT = VCC(max), TA = 25°C
ILIMIT(SRC) VOUT = GND, TA = 25°C
Vnpp
25
–4
–
mA
mA
mVpp
V
Output Current Limit
–1.6
6
Output Noise Peak to Peak3
Output Zener Clamp Voltage
Output Load Resistance4
Output Load Capacitance4,5
–
VZOUT
RLOAD
CLOAD
TA = 25°C
29
10
–
–
–
VOUT to VCC, VOUT to GND
VOUT to GND
BW = 3000 Hz
BW = 1500 Hz
BW = 375 Hz
–
–
kΩ
nF
–
10
0.75
1.4
4.0
–
–
0.6
1.1
3.2
0.5
0.9
3.24
ms
ms
ms
ms
ms
ms
Power-On Time4,6,7
Response Time7,8
tPO
–
–
BW = 3000 Hz
BW = 1500 Hz
BW = 375 Hz
–
tRESP
–
–
–
–
11 G (gauss) = 0.1 mT (millitesla).
2See Protection Features section.
3Capacitor of 10 nF connected between output and ground.
4Determined by design.
5Clarity of a Read Acknowledge message from the device to the controller will be affected by the amount of capacitance and wire inductance on the device output. In such
case, it is recommended to slow down the communication speed, and to lower the receiver threshold for reading digital Manchester signal to 1 V.
6Defined as time from VCC reaching VCC(min) to VOUT reaching 90% of its steady state. See Definitions of Terms section.
7Parameter is verified by lab characterization with a limited amount of samples.
8Defined time from step in gauss of applied magnetic field to VOUT step reaching 90% of its steady state. See Definitions of Terms section.
Allegro MicroSystems, LLC
115 Northeast Cutoff
5
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
MAGNETIC CHARACTERISTICS: valid across full operating temperature range, TA, and supply voltage range, VCC
BYPASS = 10 nF; unless otherwise specified
,
C
Characteristics
Symbol
Test Conditions
Min.
Typ.
Max.
Unit1
Factory Programmed Device Values2
Magnetic Input Signal Range
Magnetic Input Signal Offset
Output Sensitivity
BIN
SENS_COARSE = 4
–
±300
0
–
G
V
BINOFFSET SIG_OFFSET = 0
–
–
Sens
SENS_MULT = 0, TA = 25°C
BIN = 0 G, TA = 25°C
8.08
2.42
8.33
2.50
8.58
2.58
mV/G
V
Quiescent Voltage Output
VOUT(Q)
VCC
VSAT(H)
–
VCLP(H)init
VCLP(L)init
–
–
V
Output Clamp Initial Voltage
–
–
–
–
–
VSAT(L)
<±0.03
<±0.02
<±0.7
–
–
–
–
–
V
TA = –40°C to 25°C
TA = 25°C to 150°C
TA = –40°C to 25°C
TA = 25°C to 150°C
%/°C
%/°C
mV/°C
mV/°C
Sensitivity Drift Over Temperature3
DSens
Offset (QVO) Drift Over Temperature4
11 G (gauss) = 0.1 mT (millitesla).
DVOUT(Q)
<±0.1
2Device performance is optimized for the input magnetic range of SENS_COARSE = 4 and input offset of SIG_OFFSET=0. If a different magnetic input range or signal
offset is required, please see the tables in the section EEPROM Customer-Programmable Parameter Reference, near the end of this document.
3Does not include drift over lifetime and package hysteresis.
4Offset drifts with temperature changes will be altered from the factory programmed values if Magnetic Input Signal Range is changed. If changes in Magnetic Input Signal
Range cannot be avoided because of application requirements, please contact Allegro for detailed information.
Allegro MicroSystems, LLC
115 Northeast Cutoff
6
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
PROGRAMMABLE CHARACTERISTICS: valid through full operating temperature range, TA, and supply voltage, VCC
BYPASS = 10 nF, unless otherwise specified
,
C
Characteristics
Symbol
Test Conditions
Min.
Typ.
Max.
Unit1
Internal Bandwidth Programming2
Bandwidth Programming Bits
BW
–
2
–
–
bit
TA = 25°C; for programming values, see BW in
EEPROM Structure section
Bandwidth Programming Range
BW
375
3000
Hz
Bandwidth Post-Programming
Tolerance
∆BW
TA = 25°C, measured as a percentage of BW
–
±5
–
%
Fine Quiescent Voltage Output (QVO)2
Fine Quiescent Voltage Output
Programming Bits
QVO_FINE
–
–1
–
12
–
–
+1
–
bit
V
Fine Quiescent Voltage Output
Programming Range
QVO_FINE TA = 25°C, BIN = 0 G, VOUT(Q) = 2.5 V
Fine Quiescent Voltage Output
Programming Step Size
StepQVO_
TA = 25°C, BIN = 0 G
1.22
mV
FINE
Output Sensitivity2
SENS_COARSE = 4, Measured at VCC = 5 V,
SENS_OUT
TA = 25°C
Output Sensitivity
5
–
0
–
12
–
11.6
–
mV/G
bit
Sensitivity Multiplier Programming Bits
Sensitivity Multipler Programming
SENS_MULT
SENS_MULT
TA = 25°C
TA = 25°C
2
–
Range
Sensitivity Multiplier Programming
Step Size
StepSENS_
MULT
–
0.00048
–
–
Linearization2
data
sampling
point
Linearization Positions
–
–
33
12
–
–
LINPOS_
COEFF
Linearization Position Coefficient Bits
LIN_x, programmed with output fitting method
bit
Output Polarity Bit
Input Polarity Bit
LIN_OUTPUT_INVERT
LIN_INPUT_INVERT
–
–
1
1
–
–
bit
bit
Continued on the next page…
Allegro MicroSystems, LLC
115 Northeast Cutoff
7
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
PROGRAMMABLE CHARACTERISTICS (continued): valid through full operating temperature range, TA, and supply volt-
age, VCC , CBYPASS = 10 nF, unless otherwise specified
Characteristics
Symbol
Test Conditions
Min.
Typ.
Max.
Unit1
Temperature Compensation (TC)2
TC1_SENS_CLD, TA = –40°C
TC1_SENS_HOT, TA = 150°C
–
–
8
8
–
–
bit
bit
1st Order Sensitivity TC Programming
Bits
TC1_SENS_
CLD
TC1_SENS_
HOT
Typical 1st Order Sensitivity TC
Programming Range3
– 98
–
+291
m%/°C
Typical 1st Order Sensitivity TC
Programming Step Size3
StepTC1SENS
–
1.53
–
m%/°C
TC2_SENS_CLD, TA = –40°C
TC2_SENS_HOT, TA = 150°C
–
–
9
9
–
–
bit
bit
2nd Order Sensitivity TC Programming
Bits
TC2_SENS_
CLD
TC2_SENS_
HOT
Typical 2nd Order Sensitivity TC
Programming Range4
–1.53
–
+1.53
m%/°C2
2nd Order Sensitivity TC Programming
Step Size4
StepTC2SENS
–
–
0.00596
–
–
m%/°C2
bit
1st Order Magnetic Offset TC
Programming Bits
TC1_OFFSET
8
–
Typical 1st Order Magnetic Offset TC
Programming Range
TC1_OFFSET
–122
–
+122
–
mG/°C
mG/°C
1st Order Magnetic Offset TC Step
Size
StepTC1_
OFFSET
0.954
Output Clamping Range2
CLAMP_HIGH
CLAMP_LOW
–
–
6
6
–
–
bit
bit
Clamp Programming Bits
CLAMP_HIGH, measured as VOUT, TA = 25°C,
VCC = 5 V
VCC –
VSAT(H)
VCLP(H)
VCLP(L)
2.54
–
–
V
V
Output Clamp Programming Range5
Clamp Programming Step Size
CLAMP_LOW, measured as VOUT, TA = 25°C,
VCC = 5 V
VSAT(L)
2.46
StepCLP(H) Measured as ΔVOUT, TA = 25°C
StepCLP(L) Measured as ΔVOUT, TA = 25°C
–
–
39
39
–
–
mV
mV
Continued on the next page…
Allegro MicroSystems, LLC
115 Northeast Cutoff
8
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
PROGRAMMABLE CHARACTERISTICS (continued): valid through full operating temperature range, TA, and supply volt-
age, VCC , CBYPASS = 10 nF, unless otherwise specified
Characteristics
Symbol
Test Conditions
Min.
Typ.
Max.
Unit1
Accuracy
Linearity Sensitivity Error
LinERR
–1
–
–
1
–
%
%
Variation on final programmed Sensitivity value;
Sensitivity Drift Due to Package
Hysteresis
∆SensPKG measured at TA = 25°C after temperature cycling
<±1
from 25°C to 150°C and back to 25°C
TA = 25°C, shift after AEC Q100 grade 0
qualification testing
Sensitivity Drift Over Lifetime
∆SensLIFE
–
±2
–
–
%
%
Ratiometry Quiescent Voltage
Output Error
RatVOUTQERR
<±0.5
–
–
–
Ratiometry Sensitivity Error
Ratiometry Clamp Error
RatSENSERR
RatCLPERR
<±1
<±1
–
–
%
%
11 G (gauss) = 0.1 mT (millitesla).
2Determined by design.
3The unit m%/C means: (10–3 × %)/C.
4The unit m%/C2 means: (10–3 × %)/C2.
5Clamp_High minimum value trim can not be lower than QVO trim. Clamp_Low maximum value trim can not be higher than QVO trim.
Allegro MicroSystems, LLC
115 Northeast Cutoff
9
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
Thermal Characteristics may require derating at maximum conditions
Characteristic
Symbol
Test Conditions*
Value Units
174 ºC/W
Package Thermal Resistance
RθJA
1-layer PCB with copper limited to solder pads
*Additional thermal information available on Allegro website.
Power Dissipation versus Ambient Temperature
1100
1000
900
800
1-layerPCB, Package KT
(RθJA = 174 C/W)
700
600
500
400
300
200
100
0
20
40
60
80
100 120 140 160 180
Temperature (°C)
Allegro MicroSystems, LLC
115 Northeast Cutoff
10
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
CHARACTERISTIC PERFORMANCE
Average Supply Current versus Supply Voltage
Average Supply Current (On) versus Temperature
12.0
11.6
11.2
10.8
10.4
10.0
9.6
12.0
11.6
V
CC
(V)
11.2
10.8
10.4
10.0
9.6
4.5
T
A
(°C)
-40
5.0
5.5
-20
0
25
50
75
100
125
150
9.2
9.2
8.8
8.8
8.4
8.4
8.0
4.0
8.0
-60
4.5
5.0
5.5
6.0
6.0
6.0
-40
-20
0
20
40
60
80
100 120 140 160
Supply Voltage, V (V)
Ambient Temperature, T (°C)
A
CC
Output Saturation Voltage (Low) versus
Average Supply Voltage
Output Saturation Voltage (Low) versus
Average Temperature
300
250
200
150
100
50
300
250
200
150
100
50
T
A
(°C)
-40
-20
0
V
CC
(V)
25
4.5
5.0
5.5
50
75
100
125
150
0
4.0
0
-60
-40
-20
0
20
40
60
80
100 120 140 160
4.5
5.0
5.5
Supply Voltage, V (V)
Ambient Temperature, T (°C)
A
CC
Output Saturation Voltage (High) versus
Average Temperature
Output Saturation Voltage (High) versus
Average Supply Voltage
300
250
200
150
100
50
300
250
200
150
100
50
T
A
(°C)
-40
-20
0
V
CC
(V)
25
4.5
5.0
5.5
50
75
100
125
150
0
-60
0
4.0
-40
-20
0
20
40
60
80
100 120 140 160
4.5
5.0
5.5
Ambient Temperature, T (°C)
Supply Voltage, V (V)
A
CC
Allegro MicroSystems, LLC
115 Northeast Cutoff
11
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
Factory Programmed Sensitivity Drift
Factory Programmed Sensitivity
versus Ambient Temperature
versus Ambient Temperature
0.050
0.040
0.030
0.020
0.010
0
8.580
8.530
8.480
8.430
8.380
8.330
8.280
8.230
8.180
8.130
8.080
Average + 3 sigma
Average
Average + 3 sigma
Average
-0.010
-0.020
-0.030
-0.040
-0.050
Average – 3 sigma
Average – 3 sigma
∆T relative to T = 25°C
A
A
-80 -60
-40
-20
0
20
40
60
80
100 120 140
-60
-40
-20
0
20
40
60
80
100 120 140 160
Ambient Temperature, T (°C)
Change in Ambient Temperature, ∆T (°C)
A
A
Factory Programmed Quiescent Voltage Output
Factory Programmed Quiescent Voltage Output
Drift versus Ambient Temperature
versus Ambient Temperature
0.700
2.580
2.560
0.500
Average + 3 sigma
0.300
2.540
Average + 3 sigma
Average
2.520
2.500
2.480
2.460
2.440
2.420
Average
0.100
-0.200
-0.300
-0.500
-0.700
Average – 3 sigma
Average – 3 sigma
∆T relative to T = 25°C
A
A
-80 -60
-40
-20
0
20
40
60
80
100 120 140
-60
-40
-20
0
20
40
60
80
100 120 140 160
Change in Ambient Temperature, ∆T (°C)
Ambient Temperature, T (°C)
A
A
Positive Linearity versus Ambient Temperature
Negative Linearity versus Ambient Temperature
3.0
3.0
2.0
1.0
2.0
1.0
Average
Average
Average + 3 sigma
Average + 3 sigma
0
0
-1.0
-2.0
-3.0
Average – 3 sigma
Average – 3 sigma
-1.0
-2.0
-3.0
-60
-40
-20
0
20
40
60
80
100 120 140 160
-60
-40
-20
0
20
40
60
80
100 120 140 160
Ambient Temperature, T (°C)
Ambient Temperature, T (°C)
A
A
Allegro MicroSystems, LLC
115 Northeast Cutoff
12
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
Average Quiescent Voltage Output Ratiometry
Average Sensitivity Ratiometry
versus Ambient Temperature
versus Ambient Temperature
0.5
0.4
0.3
0.2
0.1
0
0.5
0.4
0.3
0.2
0.1
0
V
CC
(V)
V
(V)
CC
4.5
5.5
4.5
5.5
-0.1
-0.2
-0.3
-0.4
-0.5
-0.1
-0.2
-0.3
-0.4
-0.5
-60
-40
-20
0
20
40
60
80
100 120 140 160
-60
-40
-20
0
20
40
60
80
100 120 140 160
Ambient Temperature, T (°C)
Ambient Temperature, T (°C)
A
A
Allegro MicroSystems, LLC
115 Northeast Cutoff
13
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
FUNCTIONAL DESCRIPTION
This section provides descriptions of the operating features
and subsystems of the A1340. For more information on spe-
cific terms, refer to the Definitions of Terms section. Tables of
EEPROM parameter values are provided in the EEPROM Struc-
ture section.
BANDWIDTH SELECTION
The 3-dB bandwidth, BW, determines the frequency at which
the DSP function imports data from the analog front end A-to-D
convertor. It is programmed by setting the BW parameter in the
EEPROM. The values chosen for BW and RANGE affect the
DSP stage output resolution and the Response Time, tRESP. These
tradeoffs are represented in the Electrical Characteristics table,
above.
Signal Processing Parameter Setting
The A1340 has customer-programmable parameters that allow
the user to optimize the signal processing performed by the
A1340. Customer-programmable parameters apply to digital
signal processing (DSP) stage. Programmed settings are stored in
onboard EEPROM. The programming communication protocol is
described in the Programming Serial Interface section.
TEMPERATURE COMPENSATION
The magnetic properties of materials can be affected by changes
in temperature, even within the rated ambient operating tempera-
ture range, TA. Any change in the magnetic circuit due to temper-
ature variation causes a proportional change in the device output.
The device can be compensated internally using the Temperature
Compensation (TC) circuitry. TC coefficients can be programmed
for Sensitivity and magnetic offset. The effect of temperature is
referred to as drift.
The initial analog processing is factory programmed to match
the application environment in terms of magnetic field range and
offset. This allows optimization of the electrical signal presented
to the DSP stage:
YAD (V) = SENS_COARSE (mV/G) × BIN
+ SIG_OFFSET (V) + VOUT(Q)
(1)
Table 1: Bandwidth-Related Tradeoffs
where:
Bandwidth Selection, BW
(kHz)
DSP Output Resolution
(bit)
YAD is the output of the analog subsystem to the A-to-D con-
verter,
0.375
1.500
3.000
12
SENS_COARSE is the factory-set coarse sensitivity,
BIN is the current magnetic input signal,
SIG_OFFSET the factory-set signal offset, and
11 to 12
10 to 11
VOUT(Q) is the quiescent voltage output with no factory compen-
sation.
QOUT
The DSP stage provides customer-programmable sensitivity
(gain) fine offset adjusting, TC processing, bandwidth, clamp,
and linearization selection.
TC1_O
FFSET
Code 0
Output is a digital voltage signal, proportional to the applied
magnetic signal.
Digital Signal Processing
The digitized analog signal is digitally processed to optimize
accuracy and resolution for conversion to the device output stage.
An advanced linearization feature also is available.
TA
Figure 2: The 1st Order Magnetic Offset Temperature
Compensation Coefficient (TC1_OFFSET)
TC1_OFFSET is used for linear adjustment of device output for tem-
perature changes.
Allegro MicroSystems, LLC
115 Northeast Cutoff
14
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
For magnetic offset, compensation for 1st Order Magnetic Offset
TC, TC1_OFFSET, is a linear algorithm accounting for effects of
ambient temperature changes during device operation (see Fig-
ure 2). It can be programmed using the TC1_OFFSET parameter
in a range of ±122 mG/°C. This compensation is applied in DSP,
after bandwidth selection.
25°C
TC1_SE
NS_CLD
Code 0
0
T Code
NS_HO
TC1_SE
Sensitivity drift compensation is customer-programmed
(described below), within a framework of programmed tempera-
ture compensation. Optional temperature compensation for Sen-
sitivity can be applied using built-in first-order and second-order
algorithms. Both approaches adjust the device gain in response
to input signal drift by adding or subtracting a value. The coef-
ficients are programmed separately for temperatures above 25°C
and below 25°C, as shown in Table 2. The resulting functions are
illustrated in figure 4).
TA
25°C
TC2_SEN
e
S_CLD Code
0
ode 0
S_HOT C
TC2_SEN
TA
Table 2: Sensitivity Temperature Compensation Op-
tions
Figure 4: Sensitivity TC Functions:
(upper) first order; (lower) second order
TA Range
< 25°C
> 25°C
1st Order
2nd Order
TC1_SENS_CLD
TC2_SENS_CLD
TC1_SENS_HOT
TC2_SENS_HOT
Sensitivity
Multiplier
/Fine QVO
Adjustment
Linear-
ization
Output
TC Codes
Applied for
A = 25°C
Sensitivity
and Offset
Applied
Linearization
Coefficients
Applied
Clamps
Are Set
T
Figure 3: Signal Path for Digital Subsystem
Allegro MicroSystems, LLC
115 Northeast Cutoff
15
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
Either first-order or second-order, or both TC algorithms can
be applied. To apply an algorithm, select non-zero coefficients
for the corresponding EEPROM parameters (TC1_SENS_CLD
and TC1_SENS_HOT for first-order, TC2_SENS_CLD and
TC2_SENS_HOT for second order). If a method should not be
used, set the corresponding EEPROM parameter values to zero. If
both are selected, the A1340 applies the first-order, and then the
second-order algorithm during this stage.
OUTPUT FINE OFFSET ADJUSTMENT
The Fine Offset adjustment is the segment of the DSP signal used
to trim the device output, VOUT
.
QVO_FINE is a customer-programmable parameter that sets the
Quiescent Voltage Output, VOUT(Q) , which is device output when
there is no significant applied magnetic field. The programmed
value sets the DSP output, YDA , taking into account the selected
Sensitivity:
The programmed values set the temperature compensation, YTC
,
according to the following formula:
YDA = SENS_MULT × YTC (V) + QVO_FINE (V)
(2)
Y
TC (V) = YAD (V) + [ (TC1_SENS (m%/°C)
SENS_OUT (mV/G) = SENS_MULT × SENS (mV/G) (3)
× ΔTA (°C)) + (TC2_SENS (m%/°C2) × ΔTA2 (°C)) ]
× ( YAD (V) – SIG_OFFSET (V) )
where SENS_MULT is the multiplication factor from 0.6 to 1.4.
QVO_FINE is set as a percentage of VOUT
.
+ TC1_OFFSET (G/°C) × SENS_COARSE_COEF
× 5 (mV/G) × ΔTA (°C)
(2)
LINEARIZATION OF OUTPUT
where:
AD is the input from the analog subsystem via the A-to-D con-
verter,
Magnetic fields are not always linear throughout the full range
of target positions, such as in the case of ring magnet targets
rotated in front of a non-back-biased linear Hall sensor IC, shown
in Figure 5. The A1340 provides a programmable linearization
feature that allows adjustment of the transfer characteristic of the
device so that, as the actual position of the target changes, the
resulting changes in the applied magnetic field can be output as
corresponding linear increments.
Y
TC1_SENS is the first-order coefficient: either TC1_SENS_HOT
or TC1_SENS_CLD depending on TA,
TC2_SENS is the second-order coefficient: either TC2_SENS_
HOT or TC2_SENS_CLD depending on TA,
ΔTA is the change in ambient temperature from 25°C (for exam-
ple: at 150°C, ΔTA = 150°C – 25°C = 125°C, or at –40°C,
ΔTA = –40°C – 25°C = –65°C), and
100
90
80
Initial Output
70
SIG_OFFSET (set to 0) is the factory programmed addition to the
magnetic offset parameter (sets the centerpoint of YAD), and
60
50
Linearized Output
40
30
20
10
0
SENS_COARSE_COEF = SENS_COARSE(code 0)
SENS_COARSE(factory code) (sets the factory-programmed sensi-
tivity of the YAD function).
/
-4
-3
-2
-1
0
1
2
3
4
DIGITAL OUTPUT SENSITIVITY (GAIN) ADJUST-
MENT
Ring Magnet Rotation (°)
Sensitivity is applied in the DSP subsystem, after bandwidth
selection and temperature compensation.
Figure 5: Example of Linearization of a Sinusoidal Mag-
netic Signal Generated by a Rotating Ring Magnet
Note: If Sensitivity must be adjusted more than 20% from the
nominal value, please consider switching input magnetic range
for the optimization of A-to-D input.
Allegro MicroSystems, LLC
115 Northeast Cutoff
16
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
In order to achieve this, an initial set of linearization coefficients
has to be created. The user takes 33 samples of BIN: at the start
and at every 1/32 interval of the full input range. The user then
enters these 33 values into the Allegro ASEK programming utility
for the A1340, or an equivalent customer software program, and
generates coefficients corresponding to the values. The user then
uses the software load function to transmit the coefficients to the
EEPROM (LINPOS_COEFF parameter). The user then sets the
LIN_TABLE_DONE parameter to 1.
384 LSB is treated as input to the inverse linearization function,
after rescaling to the x axis as follows:
(384 – 128(offset)) × [32 / (3968(LSBmax)
– 128(LSBmin))] + 1 = 3.2
For x = 3.2, the inverse function will give output of 570 LSB
which is right on the curve of the linear output signal.
OUTPUT POLARITY
Each of the coefficient values can be individually overwritten
during normal operation. Figure 6 shows an example input-output
curve. The y axis represents the 32 equal full scale position
segments, and the x axis represents the the range of movement.
When the A1340 is in operation, it applies a linearization curve
built from the 33 coefficients provided by the user. For example,
at position 5 the device originally would output 384 LSB of mag-
netic field internal to device before the D-to-A converter. This
Device Output Polarity can be changed using the linearization
table, and the LIN_INPUT_INVERT and LIN_OUT_INVERT
bits.
In order to invert the device output polarity with no lineariza-
tion, the linearization function must be set to gain 1 (lineariza-
tion table coefficients are decimal values from 0 to 4096 with
steps of 128 codes), and one of the bits LIN_INPUT_INVERT or
LIN_OUT_INVERT must be set to 1.
4096
3968
3840
3712
3584
3456
3328
3200
3072
2944
2816
2688
2560
2432
2304
2176
2048
1920
1792
1664
Output Signal
Input Signal
Linearization
Function
1536
(2) Rescaled x = 3.2,
yields LSB = 570
1408
1280
1152
1024
896
768
640
512
(3) Final result is LSB = 570 for the input point 5
(1) x at 5, preprocessing LSB = 384
384
256
128
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
Positions
Figure 6: Sample of Linearization Function Transfer Characteristic.
Allegro MicroSystems, LLC
115 Northeast Cutoff
17
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
If the goal is to change output polarity and apply linearization,
the output polarity should be changed by setting the gain of the
linearization function to 1 and setting the LIN_INPUT_INVERT
bit to 1. Then user can collect 33 points for linearization and
calculate the coefficients. After the coefficients are loaded
into the device, successful linearization will be applied by
leaving the LIN_INPUT_INVERT bit set to 1 and setting the
LIN_TABLE _DONE bit to 1.
the external controller. The A1340 provides lockout protection
for undervoltage on the supply line. Lockout features protect the
A1340 internal circuitry and prevent spurious output when VCC
is out of specification. Diagnostic circuitry reuses the output pin
(VOUT) to provide feedback to the external controller.
If the supply voltage drops below VCC(UV_low) the device inter-
nal lockout function isolates the onboard processing circuits and
pulls the VOUT pin to a diagnostic level. As the supply voltage
rises above VCC(UV_high) the diagnostic condition is removed.
OUTPUT SIGNAL CLAMPS SETTING
To eliminate the effects of outlier points, the A1340 Clamp
Range, VCLP, is initially set to a high limit of VCC – Vsat for high
clamp and 0 V + Vsat for low clamp, and can be adjusted using
the CLAMP_HIGH and CLAMP_LOW parameters.
Open Circuit Detection
Diagnostic circuitry reuses the output pin (VOUT) to provide
feedback to the external controller if a resistor, ROCD, is placed
between VOUT and a separate VBAT or ground reference, as
shown in table 3. When an open circuit occurs on any combina-
tion of A1340 pins, a corresponding VOUT level is generated.
PROTECTION FEATURES
Lockout and clamping features protect the A1340 internal cir-
cuitry and prevent spurious output when supply voltage is out of
specification. Open circuit detection is also provided.
TYPICAL APPLICATION
Multiple A1340 linear devices can be connected to the external
controller as shown in Figure 7. However, EEPROM program-
ming in the A1340 occurs when the external control unit excites
the A1340 VOUT pin by EEPROM pulses generated by the ECU.
Whichever A1340s are excited by EEPROM pulses on their
VOUT pin will accept commands from the controller.
Operating Undervoltage Lockout
Lockout features protect the A1340 internal circuitry and prevent
spurious output when VCC is out of specification. Diagnostic
circuitry reuses the output pin (VOUT) to provide feedback to
Table 3: Open Circuit Diagnostic Truth Table
Node A Node B Node C
VOUT State
VCC1
VBAT Referenced
Open
Closed
Open
Closed
Open
Closed
Closed
Closed
Open
0 V to VBAT
VOUT(Q)
GND
V
V
VCC
CC
BAT
B
0.01 µF
OUT1
A
A1340
VOUT
VCC
R
Open
OCD
GND
A1340
VOUT
Open
Closed
Open
VBAT
ECU
GND
Closed
Closed
Open
VCC
C
VCC2
Closed
Open
VCC to VBAT
Ground Referenced
VCC
Closed
Closed
Closed
Open
Open
Closed
Open
Closed
Open
VOUT(Q)
0 V to VCC
VCC
0.01 µF
V
OUT2
CC
A1340
VOUT
A
VCC
A1340
VOUT
GND
Open
Open
Closed
Open
GND
R
B
GND
OCD
Open
Closed
Closed
GND
C
Open
Closed
GND
Figure 7: Typical Application with Multiple A1340s
Allegro MicroSystems, LLC
115 Northeast Cutoff
18
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
PROGRAMMING SERIAL INTERFACE
The A1340 incorporates a serial interface that allows an external
controller to read and write registers in the A1340 EEPROM and
Writing the Access Code
volatile memory. The A1340 uses a point-to-point communication If the external controller will write to or read from the A1340
protocol, based on Manchester encoding per G. E. Thomas (a ris- memory during the current session, it must establish serial com-
ing edge indicates 0 and a falling edge indicates 1), with address
and data transmitted MSB first.
munication with the A1340 by sending a Write command includ-
ing the Access Code within 70 ms after powering up the A1340. If
this deadline is missed, all write and read access is disabled until
the next power-up.
Transaction Types
Each transaction is initiated by a command from the controller;
the A1340 does not initiate any transactions. Two commands are
recognized by the A1340: Write and Read. There also are three
special function Write commands: Write Access Code, Write Dis-
able Output, and Write Enable Output. One response frame type
is generated by the A1340, Read Acknowledge.
Writing to Non-Volatile EEPROM
When a Write command requires writing to non-volatile
EEPROM (all standard Writes), after the Write command the
controller must also send two Programming pulses, well-sepa-
rated, long high-voltage strobes via the VOUT pin. These strobes
are detected internally, allowing the A1340 to boost the voltage
on the EEPROM gates.
If the command is Read, the A1340 responds by transmitting the
requested data in a Read Acknowledge frame. If the command is
any other type, the A1340 does not acknowledge.
To ensure these strobes are properly received, the controller must
suppress the normal device output on the VOUT pin (that is, the
As shown in Figure 8, The A1340 receives all commands via the
VCC pin. It responds to Read commands via the VOUT pin. This linear output voltage in response to magnetic field input). To do
implementation of Manchester encoding requires the commu-
nication pulses be within a high (VMAN(H)) and low (VMAN(L)
so, the external controller sends a Write Disable Output command
before transmitting the strobes. This puts the VOUT pin into a
)
range of voltages for the VCC line and the VOUT line. The Write high impedance state. After writing is complete, the controller
command pulses to EEPROM are supported by two high voltage
pulses on the VOUT line.
must send an Write Enable Output command to restore VOUT to
normal operation. The required sequence is shown in Figure 9.
Write/Read Command –
Manchester Code
ECU
VCC
High Voltage pulses to
activate EEPROM cells
A1340
V
OUT
Read Acknowledge
– Manchester Code
Figure 8: Top-Level Programming Interface
Allegro MicroSystems, LLC
115 Northeast Cutoff
19
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
Acknowledge frame has been received from the A1340, the
Writing to Volatile Registers
controller must send a Write Enable Output command to restore
VOUT to normal operation. The required sequence is shown in
Figure 9.
Writing to the volatile register 0x24 is done for Write Access
Code, Write Disable Output, and Write Enable Output com-
mands. This requires the external controller to send the Write
command on the VCC pin. Successive Write commands to vola-
tile memory must be separated by tWRITE . The required sequence
is shown in Figure 9.
Error Checking
The serial interface uses a cyclic redundancy check (CRC) for
data-bit error checking (synchronization bits are ignored during
the check).
Reading from EEPROM
The CRC algorithm is based on the polynomial
For proper reading from the A1340, it is recommended that the
output be disabled before a Read command is sent. Otherwise
the external controller may continue to track the magnetic field
input until the first edge of the Read Acknowledge frame. In that
case the controller would be required to distinguish between the
output associated with the magnetic field and the response to the
Read command.
g(x) = x3 + x + 1 ,
and the calculation is represented graphically in Figure 10.
The trailing 3 bits of a message frame comprise the CRC token.
The CRC is initialized at 111.
To disable output, the external controller sends a Write Disable
Output command before transmitting the Read command. This
puts the VOUT pin into a high impedance state. After writing
is complete, the controller must send a Write Enable Output
command to restore VOUT to normal operation. After the Read
Input Data
C0
C1
C2
1x0
1x1
0x2
1x3 = x3 + x + 1
Figure 10: CRC Calculation
VCC
Write Access
Command
Disable Output
Command
Write
Command
Enable Output
Command
EEPROM
Programming
Pulses
Write to
EEPROM
High
High
Impedance
Normal Operation
Normal Operation
Impedance
VOUT
GND
t
t
<70 ms from power-on
tDIS_OUT
tsPULSE(E) tWRITE(E)
tENB_OUT
Write to
Volatile Memory
(Register 0x24)
VCC
Write Access
Command
Previous
Command
Write
Command
Next
Command
<70 ms from
power-on
tWRITE
tWRITE
tWRITE
VCC
Write Access
Command
Disable Output
Command
Read
Command
Enable Output
Command
Read from
EEPROM
<70 ms from power-on
High
Impedance
High
Impedance
Read
Acknowledge
Normal Operation
Normal Operation
VOUT
GND
t
tDIS_OUT
tSTART_READ
tSTART_READ
tENB_OUT
Figure 9: Programming Read and Write Timing Diagrams
(see Serial Interface Reference section for definitions)
Allegro MicroSystems, LLC
115 Northeast Cutoff
20
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
Serial Interface Reference
Table 4: Serial Interface Protocol Characteristics1
Characteristics
Symbol
Note
Min.
Typ.
Max.
Unit
Input/Output Signal Timing
Customer Access Code should be fully entered
in less than tACC , measured from when VCC
Access code Time Out
Baud Rate
tacc
–
5
–
–
70
ms
crosses VCC(UV_high)
.
Defined by the input message bit rate sent from
the external controller
100
kbps
Data bit pulse width at 5 kbps
195
9.5
200
10
–
205
10.5
+11
µs
µs
%
Bit Time
tBIT
Data bit pulse width at 100 kbps
Deviation in tBIT during one command frame
Bit Time Error
errTBIT
–11
Required delay from the trailing edge of certain
Write command frames to the leading edge of a
following command frame
Volatile Memory Write Delay
Non-Volatile Memory Write Delay
Read Acknowledge Delay
Read Delay2
tWRITE
2 × tBIT
–
–
–
–
µs
µs
µs
µs
µs
µs
Required delay from the trailing edge of the
tWRITE(E) second EEPROM Programming pulse to the
leading edge of a following command frame
2 × tBIT
Required delay from the trailing edge of a Read
Acknowledge frame to the leading edge of a
following command frame
tREAD
2 × tBIT
25 µs –
–
–
Delay from the trailing edge of a Read
command frame to the leading edge of the Read
Acknowledge frame
50 µs –
150 µs –
tSTART
_
READ
0.25×tBIT 0.25×tBIT 0.25×tBIT
Delay from the trailing edge of a Disable Output
tDIS_OUT command frame to the device output going from
normal operation to the high impedance state
1 µs –
5 µs –
15 µs –
Disable Output Delay2
0.25×tBIT 0.25×tBIT 0.25×tBIT
Delay from the trailing edge of an Enable Output
tENB_OUT command frame to the device output going from
the high impedance state to normal operation
1 µs –
5 µs –
15 µs –
Enable Output Delay2
0.25×tBIT 0.25×tBIT 0.25×tBIT
EEPROM Programming Pulse
EEPROM Programming Pulse
Setup Time
Delay from last edge of write command to start
tsPULSE(E)
40
–
–
μs
of EEPROM programming pulse
Input/Output Signal Voltage
Applied to VCC line
7.3
–
–
–
–
V
V
Manchester Code High Voltage
VMAN(H)
VCC
VSAT(H)
–
Read from VOUT line
Applied to VCC line
VMAN(L)
–
–
–
–
5.7
V
V
Manchester Code Low Voltage
1Determined by design.
Read from VOUT line
VSAT(L)
2In the case where a slower baud rate is used, the output responds before the transfer of the last bit in the command message is completed.
Allegro MicroSystems, LLC
115 Northeast Cutoff
21
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
Serial Interface Message Structure
The general format of a command message frame is shown in
Figure 11. Note that, in the Manchester coding used, a bit value
of 1 is indicated by a falling edge within the bit boundary, and
a bit value of zero is indicated by a rising edge within the bit
boundary.
Read/Write
Synchronize
Memory Address
Data
CRC
0
0 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 . . . 0/1 0/1 0/1 0/1
MSB
MSB
The bits are described in Table 5.
Manchester Code per G. E. Thomas
Bit boundaries
0 0 1 1 0
Figure 11: General Format for Serial Interface
Commands
Table 5: Serial Interface Command General Format
Quantity
of Bits
Parameter Name
Values
Description
2
Synchronization
00
0
Used to identify the beginning of a serial interface command
[As required] Write operation
1
Read/Write
1
[As required] Read operation
6
Variable
3
Address
Data
0/1
0/1
0/1
[Read/Write] Register address (volatile memory or EEPROM)
[As required] 30 bits of data
CRC
Incorrect value indicates errors
Allegro MicroSystems, LLC
115 Northeast Cutoff
22
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
The following command messages can be exchanged between the
device and the external controller:
• Read
• Read Acknowledge
• Write
• Write Access Code
• Write Disable Output
• Write Enable Output
For EEPROM address information, refer to the EEPROM
Structure section.
READ
Provides the address in A1340 memory to be accessed to transmit the contents to the external controller in the next
Read Acknowledge command.
Function
A timely Write Access Code command is required once, at power-up of the A1340.
Sent by the external controller on the A1340 VCC pin.
Sent after a Write Disable Output command.
Syntax
Related Commands
Read Acknowledge
Read/Write
Memory Address
CRC
Synchronize
Pulse Sequence
0
0
1
0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1
MSB
Options
None
Address in non-volatile memory: 0XXXXX
Address in volatile memory: 100100 (Register 0x24)
Examples
Allegro MicroSystems, LLC
115 Northeast Cutoff
23
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
READ ACKNOWLEDGE
Transmits to the external controller data retrieved from the A1340 memory in response to the most recent Read
command.
Function
Sent by the A1340 on the A1340 VOUT pin.
Sent after a Read command and before a Write Enable Output command.
Syntax
Related Commands
Read
Data
(30 bits)
CRC
Synchronize
Pulse Sequence
0
0
0/1 0/1 0/1 0/1 . . . 0/1 0/1 0/1 0/1 0/1
MSB
If EEPROM Error Checking and Correction (ECC) is not disabled by factory programming, the 6 MSBs are EEPROM
data error checking bits. Refer to the EEPROM Structure section for more information.
Options
Examples
–
WRITE
Function
Transmits to the A1340 data prepared by the external controller.
Sent by the external controller on the A1340 VCC pin.
Syntax
A timely Write Access Code command is required once, at power-up of the A1340.
For writing to non-volatile memory: Sent after a Write Disable Output command.
Related Commands
Disable Output, Enable Output, Write Access Code
Read/Write
Data
Memory Address
(30 bits)
CRC
Synchronize
Pulse Sequence
0
0
0
0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 . . . 0/1 0/1 0/1 0/1
MSB MSB
Options
–
Address in non-volatile memory: 0XXXXX
Address in volatile memory: 100100 (Register 0x24)
Examples
Allegro MicroSystems, LLC
115 Northeast Cutoff
24
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
WRITE ACCESS CODE
Transmits the Access Code to the A1340; data prepared by the external controller, but must match the internal 30-bit
code in the A1340 memory.
Function
Sent by the external controller on the A1340 VCC pin.
Sent within 70 ms of A1340 power-on, and before any other command.
Syntax
Related Commands
Read/Write
Data
Memory Address
(30 bits)
CRC
Synchronize
Pulse Sequence
0
0
0
1
0
0
1
0
0
1
0
0
. . .
1
0
0
1
MSB
MSB
Options
None
Standard Customer Access Code: 0x2781_1F77 to address 0x24
Examples
WRITE DISABLE OUTPUT
Suppresses normal output from the VOUT pin to allow clear transmission of Read Acknowledge commands and
EEPROM Programming pulses. Places VOUT in a high impedance state.
Function
Sent by the external controller on the A1340 VCC pin.
For writing to non-volatile memory: Sent before each Write command.
For reading: Sent before a Read command.
Syntax
Related Commands
Write Enable Output
Read/Write
Data
Memory Address
(30 bits)
CRC
Synchronize
Pulse Sequence
0
0
0
1
0
0
1
0
0
0
. . .
0
1
0
0
0
0
0
1
0
MSB
MSB
Options
None
Examples
0x10 to address 0x24
Allegro MicroSystems, LLC
115 Northeast Cutoff
25
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
WRITE ENABLE OUTPUT
Restores normal output from the VOUT pin after a high impedance state has been imposed by a Disable Output
command.
Function
Sent by the external controller on the A1340 VCC pin.
Syntax
For writing to non-volatile memory: Sent after a Write command and corresponding EEPROM Programming pulses.
For reading: Sent after a Read Acknowledge command.
Related Commands
Write Disable Output
Read/Write
Data
Memory Address
(30 bits)
CRC
Synchronize
Pulse Sequence
0
0
0
1
0
0
1
0
0
0
. . .
0
0
0
0
0
0
0
1
1
MSB
MSB
Options
None
Examples
0x0 to address 0x24
Allegro MicroSystems, LLC
115 Northeast Cutoff
26
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
EEPROM STRUCTURE
Programmable values are stored in an onboard EEPROM,
including both volatile and non-volatile registers. Although it is
separate from the digital subsystem, it is accessed by the digital
subsystem EEPROM Controller module.
The EEPROM is organized as 30-bit wide words, and by default
each word has 24 data bits and 6 ECC (Error Checking and Cor-
rection) check bits, stored as shown in Figure 12.
EEPROM Bit
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
Contents
D23 D22 D21 D20 D19 D18 D17 D16 D15 D14 D13 D12 D11 C5 D10
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
D9
D8
D7
D6
D5
D4
C4
D3
D2
D1
C3
D0
C2
C1
C0
Figure 12: EEPROM Word Bit Sequence; C# – Check Bit, D# – Data Bit
Allegro MicroSystems, LLC
115 Northeast Cutoff
27
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
Table 6: EEPROM Register Map of Customer-Programmable Parameters (Non-Volatile Memory)
Address
0x08
0x08
0x08
0x08
0x09
0x09
0x09
0x0A
0x0A
Bits
23:15
14:6
5:2
Parameter Name
TC2_SENS_HOT
TC2_SENS_CLD
SENS_COARSE
BW
Description
DAC profile
Two’s complement
Two’s complement
Non-uniform
2nd Order Sensitivity Temperature Coefficient, ΔT (from 25°C) > 0
2nd Order Sensitivity Temperature Coefficient, ΔT (from 25°C) < 0
Factory Adjustment of the Magnetic Input Signal Range
Internal Bandwidth
1:0
Non-uniform
23:16
15:8
7:0
TC1_SENS_HOT
TC1_SENS_CLD
TC1_OFFSET
SCRATCH_C
1st Order Sensitivity Temperature Coefficient, ΔT (from 25°C) > 0
1st Order Sensitivity Temperature Coefficient, ΔT (from 25°C) < 0
1st Order Magnetic Offset Drift Compensation
Customer Scratchpad
Non-uniform
Non-uniform
Two’s complement
23:12
11:0
SENS_MULT
Output Sensitivity/ Sensitivity Multiplier
LINPOS_COEFF
(LIN_1, LIN_3, ..., LIN_31)
0x0B to 0x1A
0x0B to 0x1B
23:12
11:0
Linearization Coefficients (odd-numbered sampling positions)
Linearization Coefficients (even-numbered sampling positions)
LINPOS_COEFF
(LIN_0, LIN_2, ..., LIN_32)
0x1B
0x1B
0x1B
0x1B
0x1C
0x1C
0x1C
0x1C
0x1C
0x1C
23
22
LIN_TABLE_DONE
LIN_OUTPUT_INVERT
LIN_INPUT_INVERT
ID
Linearization Complete Flag
Linearization Output Polarity Inversion
Linearization Input Polarity Inversion
Customer Identification Number
Clamp Upper Limit
21
20:12
23:18
17:12
11
CLAMP_HIGH
CLAMP_LOW
EEPROM_LOCK1
Reserved
Clamp Lower Limit
Customer EEPROM Lock
10
Reserved for system use (customer should not write this bit)
Disable Internal Pullups on Digital Output Signals
Factory Adjustment of Input Signal Offset
9
OPEN_DRAIN
SIG_OFFSET
8:4
Two’s complement
Reserved for System Use (bits written here will not affect device
performance)
0x1C
3:2
Reserved
0x1C
0x1C
0x1D
0x1D
1
0
Reserved
Reserved
Reserved for system use (customer should not write this bit)
Reserved for system use (customer should not write this bit)
Customer Scratchpad
23:12
11:0
SCRATCH_C
QVO_FINE
Fine Quiescent Voltage Output (QVO)
Two’s complement
1Customer EEPROM lock allows the customer to lock the EEPROM registers from any further changes for the life of the device. Memory reading is still possible after the
EEPROM lock bit is set. In the case that a write command is sent to the device by accident after the EEPROM lock, the device needs to be repowered to be accessible
again for memory read.
Allegro MicroSystems, LLC
115 Northeast Cutoff
28
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
EEPROM Customer-Programmable Parameter Reference
BW (Register Address: 0x08, bits 1:0)
Filter Bandwidth
Function
Selects the filter bandwidth (3-dB frequency) for the digitized applied magnetic field signal, applied when passed to
the digital system after analog front-end processing.
Syntax
Quantity of bits: 2
–
Related Commands
00: 1500 Hz (Default)
01: (Factory use only)
10: 375 Hz
Values
11: 3000 Hz
Options
–
–
Examples
CLAMP_HIGH (Register Address: 0x1C, bits 23:18)
Clamp Upper Limit
Function
Sets the maximum valid output value.
Syntax
Quantity of bits: 6
CLAMP_LOW
Related Commands
000000: 5 V – Vsat (Default)
111111: 2.5 V for VCC = 5 V
Values
Options
The default, VCLP(H)init , is used if this parameter is not set.
When ratiometry is on (RATIOM_OFF = 0): Range is VCC / 2, up to VCC – Vsat
When ratiometry is off (RATIOM_OFF = 1): Typical value is VCC – 0.5 × VCC
× (CLAMP_HIGH / 64)
.
Examples
Allegro MicroSystems, LLC
115 Northeast Cutoff
29
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
CLAMP_LOW (Register Address: 0x1C, bits 17:12)
Clamp Lower Limit
Function
Sets the minimum valid output value.
Syntax
Quantity of bits: 6
CLAMP_HIGH
Related Commands
000000: 0 V + Vsat (Default)
111111: 2.5 V for VCC = 5 V
Values
Options
The default, VCLP(L)init , is used if this parameter is not set.
When ratiometry is on (RATIOM_OFF = 0): Range is VCC / 2, down to Vsat
.
Examples
When ratiometry is off (RATIOM_OFF = 1): Typical value is 0 V + 0.5 × VCC
× (CLAMP_LOW / 64)
ID (Register Address: 0x1B, bits 20:12)
Customer Identification Number
Available register for identifying the A1340 for multiple-unit applications.
Function
Syntax
Quantity of bits: 12
Related Commands
Values
SCRATCH_C
Free-form
Options
–
–
Examples
LIN_INPUT_INVERT (Register Address: 0x1B, bit 21)
Inverts the polarity of the input signal before it is sent into the linearization block. This
setting is effective only if LIN_TABLE_DONE is set to 1.
Function
Syntax
Quantity of bits: 1
Related Commands
LIN_x, LIN_OUTPUT_INVERT
0: No inversion of signal before input into the linearization block.
1: Input signal inverted before it is sent into the linearization block.
Values
Options
–
–
Examples
Allegro MicroSystems, LLC
115 Northeast Cutoff
30
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
LIN_OUTPUT_INVERT (Register Address: 0x1B, bit 22)
Inverts the polarity of the input signal after the linearization block. This setting is effective only if LIN_TABLE_DONE
is set to 1.
Function
Syntax
Quantity of bits: 1
LIN_x, LIN_INPUT_INVERT
Related Commands
0: No inversion of signal after processing in the linearization block.
1: Input signal inverted after processing in the linearization block.
Values
Options
–
–
Examples
LINPOS_COEFF
(LIN_0, LIN_2, ..., LIN_32) (Register Address: 0x0B to 0x1B, bits 11:0)
(LIN_1, LIN_3, ..., LIN_31) (Register Address: 0x0B to 0x1A, bits 23:12)
Linearization Coefficients
These addresses are available to store customer-generated and loaded coefficients used for linearization of the
temperature-compensated and offset digital signal. Note: These are not used by the device unless the LIN_TABLE_
DONE bit is set.
Function
Syntax
Quantity of bits: 12 (each)
LIN_x corresponds to Input Sample BINx
Coefficient data stored in two’s complement format
Values must be monotonically increasing
Related Commands
Values
LIN_INPUT_INVERT, LIN_OUTPUT_INVERT, LIN_TABLE_DONE
Calculated according to applied magnetic field
Input
Sample
Output
Position
EEPROM
Address
Input
Sample
Output
Position
EEPROM
Address
Bits
Bits
BIN0
BIN1
BIN2
BIN3
BIN4
BIN5
BIN6
BIN7
BIN8
BIN9
BIN10
BIN11
BIN12
BIN13
BIN14
BIN15
−2048
−1920
−1792
−1664
−1536
−1408
−1280
−1152
−1024
−896
0x0B
0x0B
0x0C
0x0C
0x0D
0x0D
0x0E
0x0E
0x0F
0x0F
0x10
0x10
0x11
0x11
0x12
0x12
11:00
23:12
11:00
23:12
11:00
23:12
11:00
23:12
11:00
23:12
11:00
23:12
11:00
23:12
11:00
23:12
BIN16
BIN17
BIN18
BIN19
BIN20
BIN21
BIN22
BIN23
BIN24
BIN25
BIN26
BIN27
BIN28
BIN29
BIN30
BIN31
BIN32
0
0x13
0x13
0x14
0x14
0x15
0x15
0x16
0x16
0x17
0x17
0x18
0x18
0x19
0x19
0x1A
0x1A
0x1B
11:00
23:12
11:00
23:12
11:00
23:12
11:00
23:12
11:00
23:12
11:00
23:12
11:00
23:12
11:00
23:12
11:00
128
256
384
512
640
768
896
Options
1024
1152
1280
1408
1536
1664
1792
1920
2047
−768
−640
−512
−384
−256
−128
Examples
–
Allegro MicroSystems, LLC
115 Northeast Cutoff
31
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
LIN_TABLE_DONE (Register Address: 0x1B, bit 23)
Linearization Table Loaded
Set by the customer to indicate custom coefficients have been loaded (into the LINPOS_COEFF area of EEPROM).
When this flag is set, the device uses the customer coefficients for output linearization. Allows correction for targets
that generate non-linear magnetic fields.
Function
Syntax
Quantity of bits: 1
LINPOS_COEFF
Related Commands
0: Linearization algorithm applies default coefficients to the processed signal (Default)
1: Linearization algorithm applies customer-loaded coefficients to the processed signal
Values
Options
–
–
Examples
OPEN_DRAIN (Register Address: 0x1C, bit 9:0)
Output Digital Signal Pullup Disable
Function
Switches off internal pullup resistors when digital serial data is being transmitted and uses customer pullup. (Does
not affect transmission of normal magnetic data transmission).
Syntax
Quantity of bits: 1
–
Related Commands
0: Internal output pullup enabled at all times (Default)
1: Disable internal output pullup during transmission of digital serial data
Values
Options
–
–
Examples
QVO_FINE (Register Address: 0x1D, bits 11:0)
Quiescent Voltage Output (QVO)
Function
Adjusts the device normal output (voltage response to applied magnetic field) to set the baseline output level: for a
quiescent applied magnetic field (BIN ≈ 0 G).
Quantity of bits: 12
Code stored in two’s complement format
Syntax
Related Commands
Values
SIG_OFFSET
0111 1111 1111: +49.98% of output full scale range (Default)
1000 0000 0000: –50% of output full scale range
Options
The default, VOUT(Q), is used if this parameter is not set.
–
Examples
Allegro MicroSystems, LLC
115 Northeast Cutoff
32
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
RATIOM_OFF (Register Address: 0x1C, bit 11)
Function
Output Ratiometry Disable
Syntax
Quantity of bits: 1
–
Related Commands
0: Ratiometry enabled (Default)
The output is determined by:
VOUT = 0.5 × VCC × [(BIN / RANGE (G))+1]
1: Ratiometry disabled
The output is determined by:
Values
VOUT = 2.5 (V) × [(BIN / RANGE (G))+1]
RANGE defined in SENS_COARSE table below.
Options
–
–
Examples
SCRATCH_C (Register Address: 0x1D, bits 23:12)
Customer Scratchpad
For optional customer use in storing values in the device.
Function
Syntax
Quantity of bits: 12
Related Commands
Values
ID
Free-form field
Options
–
–
Examples
Allegro MicroSystems, LLC
115 Northeast Cutoff
33
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
SENS_COARSE (Register Address: 0x08, bits 5:2)
Note: If the Coarse Sensitivity is changed, the offset drifts with temperature changes will be altered from the factory programmed values. If
changing Coarse Sensitivity cannot be avoided because of application requirements, please contact Allegro for detailed information.
Coarse Sensitivity
Sets the nominal (coarse) sensitivity of the device, SENS_COARSE, which can be defined as ΔVOUT/ΔBIN
Selection determines the RANGE, the extent of the applied magnetic flux intensity, BIN , sampled for signal
processing. (Use SIG_OFFSET to adjust the BIN level at which RANGE is centered.)
.
Function
Syntax
Quantity of bits: 4
Related Commands
SIG_OFFSET, SENS_OUT
Coarse Sensitivity at VCC = 5 V
(Typical)
(mV/G)
RANGE
(G)
Code
0000 (Default)
0001
0010
0011
0100
0101
0110
0111
5.00
16.70
12.50
10.00
8.30
6.25
4.00
3.30
±500
±150
±200
±250
±300
±400
±625
±750
Values
1000
1001
1010
1011
1100
1101
1110
1111
2.80
2.50
2.00
1.67
1.43
1.25
25.00
1.11
±875
±1000
±1250
±1500
±1750
±2000
±100
±2250
Options
–
To set a sampled BIN range of 500 G, set RANGE = ±250 G (SENS_COARSE = 0011). That would also set Coarse
Sensitivity to 10 mV/G (SENS_COARSE = 0011).
Examples
Allegro MicroSystems, LLC
115 Northeast Cutoff
34
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
SENS_MULT (Register Address: 0x0A, bits 11:0)
Sensitivity Multiplier
Function
Syntax
After temperature compensation, establishes the gain of the device in normal output (response to a change in the
applied magnetic field) by indicating a multiplier value.
Quantity of bits: 12
2.0
SENS_MULT
Value
1.0
0
0
0x800 0xFFF
SENS_MULT
Programming Code
Related Commands
Values
RANGE, TC1_SENS_CLD, TC1_SENS_HOT, TC2_SENS_CLD, TC2_SENS_HOT
RANGE: ±300 G
SENS_COARSE: 8.33 mV/G
Options
SENS_OUT = SENS_COARSE, that is, SENS_MULT = 1 (code 0) if this parameter is not set.
–
Examples
Allegro MicroSystems, LLC
115 Northeast Cutoff
35
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
SIG_OFFSET (Register Address: 0x1C, bits 8:4)
Note: If changing Coarse Magnetic Offset cannot be avoided because of application requirements, please contact Allegro for detailed informa-
tion.
Magnetic Offset Compensation (Coarse)
Adjusts the center of the selected RANGE to adapt to the application magnetic field.
(The applied offset, QVO_COARSE, is the sum of the selected SIG_OFFSET and a VOUT(Q) factor that compensates
for the magnetic back-biasing of the device.)
The offset values are expressed in terms of a percentage of the full scale of the selected RANGE and as a voltage
Function
relative to VOUT(Q)
.
Note: This is an analog domain variable, so step size is variable, and the offset values shown here represent the
expected typical value for the programmed code.
Quantity of bits: 5
Code stored in two’s complement format.
Syntax
Related Commands
RANGE, TC1_OFFSET
SIG_OFFSET
SIG_OFFSET
(Typical)
Code
(% of Full-Scale RANGE)
(ΔV)
00000 (Default)
00001
00010
00011
00100
00101
00110
00111
0.00
6.25
0.00
0.31
0.63
0.94
1.25
1.56
1.88
2.19
12.50
18.75
25.00
31.25
37.50
43.75
01000
01001
01010
01011
01100
01101
01110
01111
50.00
56.25
62.75
68.75
75.00
81.25
87.50
93.75
2.50
2.81
3.13
3.44
3.75
4.06
4.38
4.69
Values
10000
10001
10010
10011
10100
10101
10110
10111
–100.00
–93.75
–87.50
–81.25
–75.00
–68.75
–62.50
–56.25
–5.00
–4.69
–4.38
–4.06
–3.75
–3.44
–3.13
–2.81
11000
11001
11010
11011
11100
11101
11110
11111
–50.00
–43.75
–37.50
–31.25
–25.00
–18.75
–12.50
–6.25
–2.50
–2.19
–1.88
–1.56
–1.25
–0.94
–0.63
–0.31
Options
The default, VOUT(Q), is used if this parameter is not set.
To set the input range from 0 to 1000 G, with a centerpoint at +500 G:
1. If SENS_COARSE at 5 mV/G (SENS_COARSE code = 0000). This establishes a full scale input RANGE of 1000
G.
2. The full scale input value, 1000 G, is used as the start point of the offset, so:
SIG_Offset = (Centerpoint – Full scale input) / Full scale input
= 100 × (500 – 1000) / 1000 = –50%
Examples
3. Set the SIG_OFFSET code to 11000 (24), to select SIG_OFFSET = –50%.
This also has the effect of setting SIG_OFFSET = –2.5 V.
Allegro MicroSystems, LLC
115 Northeast Cutoff
36
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
TC1_OFFSET (Register Address: 0x09, bits 7:0)
Function
1st Order Magnetic Offset Temperature Compensation coefficient.
Quantity of bits: 8
Code stored in two’s complement format.
Syntax
Related Commands
Values
SIG_OFFSET, TC1_SENS_CLD, TC1_SENS_HOT, TC2_SENS_CLD, TC2_SENS_HOT
0111 1111: +122 mG/°C
1000 0000: –122 mG/°C
Options
No fine magnetic offset is applied if this parameter is not set.
–
Examples
TC1_SENS_CLD (Register Address: 0x09, bits 15:8)
TC1_SENS_HOT (Register Address: 0x09, bits 23:16)
1st Order Sensitivity Temperature Coefficient.
Specifies a compensation factor for drift in device Sensitivity resulting from changes in ambient temperature during
operation. Applies a 1st order, linear compensation algorithm. Two different parameters are set, one for increasing
values relative to TA = 25°C, and the other for decreasing values, as follows:
• TC1_SENS_HOT: ΔTA (from 25°C) > 0
Function
• TC1_SENS_CLD: ΔTA (from 25°C) < 0
Syntax
Quantity of bits: 8 (each parameter)
Related Commands
SENS_MULT, TC2_SENS_HOT, TC2_SENS_CLD
1100 0000: –98 m%/°C
Values
1011 1111: +291 m%/°C
Increments (step size) of ±1.53 m%/°C
Options
Set all bits to 0 if TC1_SENS_HOT and TC1_SENS_CLD are not used.
Refer to Temperature Compensation section.
Examples
Allegro MicroSystems, LLC
115 Northeast Cutoff
37
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
TC2_SENS_CLD (Register Address: 0x08, bits 14:6)
TC2_SENS_HOT (Register Address: 0x08, bits 23:15)
2nd Order Sensitivity Temperature Coefficient.
Specifies a compensation factor for drift in device Sensitivity resulting from changes in ambient temperature
during operation. Applies a 2nd order, quadratic compensation algorithm. Two different parameters are set, one for
increasing values relative to TA = 25°C, and the other for decreasing values, as follows:
• TC2_SENS_HOT: ΔT (from 25°C) > 0
Function
• TC2_SENS_CLD: ΔT (from 25°C) < 0
Syntax
Quantity of bits: 9 (each parameter)
Related Commands
SENS_MULT, TC1_SENS_HOT, TC1_SENS_CLD
1 0000 0000: –1.53 m%/°C
Values
0 1111 1111: +1.53 m%/°C
Increments (step size) of ±0.00596 m%/°C
Options
Set all bits to 0 if TC2_SENS_HOT and TC2_SENS_CLD are not used.
Refer to Temperature Compensation section.
Examples
Allegro MicroSystems, LLC
115 Northeast Cutoff
38
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
DEFINITIONS OF TERMS
Power-On Time, tPO
Magnetic Offset Drift Through Temperature
Range
The time required for device output to settle within ±10% of its
steady state value, after the power supply has reached its mini-
mum specified operating voltage, VCC(min). When the supply is
ramped to its operating voltage, the device requires a finite time
to power internal circuits before supplying a valid output value.
See Figure 13.
Due to internal component tolerances and thermal consider-
ations, the magnetic offset may drift from its expected value,
BOFFEXPECTED, when changes occur in the operating ambient
temperature, TA. For purposes of specification, the Offset Drift
Through Temperature Range, ∆BOFF(TC), is defined as:
BOFF(TA) – BOFFEXPECTED(TA)
Response Time, tRESP
∆BOFF(TC)
100 (%)
=
(1)
×
BOFFEXPECTED(TA)
The time interval between a) when the applied magnetic field
reaches 90% of its final intensity, and b) when the device output
reaches 90% of its change corresponding to the magnetic field
change. See Figure 14. Response time is affected by the pro-
grammed bandwidth, f3dB , for the DSP stage.
where BOFF(TA) is the actual magnetic offset at the current ambi-
ent temperature, and BOFFEXPECTED(TA) is the magnetic offset
calculated based on factory programmed parameters.
The Offset Temperature Coefficient can be seen as a representa-
tion of the offset drift over temperature in units mV/°C:
Quiescent Voltage Output (QVO), VOUT(Q)
VOUT(Q)TA – VOUT(Q)25°C
The output value in the quiescent state (when no magnetic field is
applied, BIN = 0 G).
∆VOUT
.
=
(2)
TA – 25°C
Sensitivity, Sens
where VOUT is measured quiescent output value at tempera-
ture TA.
The proportion of the output voltage to the magnitude of the
applied magnetic field. This proportionality is specified as the
Sensitivity, Sens (mV/G), and is effectively the gain of the
device.
t1
V
%
Supply Voltage
VCC(min.)
t1
Applied Magnetic Field
100
90
t1= time at which power supply reaches
minimum specified operating voltage
t1= time at which applied magnetic field
reaches 90% of operating intensity
tPO
tRESP
%
100
90
%
A1340 Output
A1340 Output
100
90
t2
t2
t2= time at which output voltage initially
generates a valid output
t2= time at which output voltage initially
reaches 90% of its corresponding value
VOUT(Q)
=
0
2.5 V (typ)
time
time
Figure 13: Definition of Power-On Time
Figure 14: Definition of Response Time
Allegro MicroSystems, LLC
115 Northeast Cutoff
39
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
Sensitivity Drift Through Temperature Range
Sens
Bx
1–
LinERRPOS
=
=
100 (%)
100 (%)
×
×
SensBx/2
Due to internal component tolerances and thermal considerations,
the Sensitivity may drift from its expected value, SensEXPECTED
when changes occur in the operating ambient temperature, TA.
For purposes of specification, the Sensitivity Drift Through Tem-
perature Range, ∆SensTC, is defined as:
,
Sens
–Bx
1–
LinERRNEG
(5)
(6)
Sens
–Bx/2
where:
SensTA – SensEXPECTED(TA)
∆SensTC
100 (%) .
=
(3)
×
|VOUT(Bx)
V
|
SensEXPECTED(TA)
–
OUT(Q)
SensBx
=
Bx
where SensTA is the actual Sens at the current ambient tem-
perature, and SensEXPECTED(TA) is the Sens calculated based on
factory programmed parameters.
and BX and –BX are positive and negative magnetic fields
Final Linearity Sensitivity Error (LinERR) is the maximum value
of the absolute positive and absolute negative linearization errors.
Note that unipolar devices only have positive linearity error
(LinERRPOS).
The Sensitivity Temperature Coefficient can be seen as a repre-
sentation of the Sensitivity drift in %/°C when when a tempera-
ture divider, ∆T = TA – 25°C, is inserted into equation 3.
Sensitivity Drift Due to Package Hysteresis,
∆SensPKG
Ratiometric
The A1340 features ratiometric output. This means that the qui-
escent voltage output, VOUT(Q), magnetic sensitivity, Sens, and
clamp voltage, VOUTCLP , are proportional to the supply voltage,
Package stress and relaxation can cause the device sensitivity at
TA = 25°C to change during and after temperature cycling. For
purposes of specification, the Sensitivity Drift Due to Package
Hysteresis, is defined as:
VCC
.
The ratiometric change in the quiescent output voltage,
RatVOUT(Q) (%), is defined as:
Sens(25°C)2 – Sens(25°C)1
(4)
∆SensPKG
100 (%)
=
×
Sens(25°C)1
VOUT(Q)VCC / VOUT(Q)5V
(7)
(8)
(9)
RatVOUT(Q)
100 (%)
=
×
VCC / 5 V
where Sens(25°C)1 is the programmed value of Sensitivity at TA =
25°C, and Sens(25°C)2 is the value of Sensitivity at TA = 25°C,
after temperature cycling.
the ratiometric change in sensitivity is defined as:
SensVCC / Sens5V
Linearity Sensitivity Error
RatSENS
100 (%)
=
×
VCC / 5 V
The A1340 is designed to provide a linear output in response to
a ramping applied magnetic field. Consider two magnetic field
strengths, B1 and B2. Ideally, the sensitivity of a device is the
same for both field strengths, for a given supply voltage and
temperature. Linearity error is present when there is a difference
between the sensitivities measured at B1 and B2.
and the ratiometric change in clamp voltage is defined as:
VCLP(VCC) / VCLP(5V)
RatVCLP
100 (%)
=
×
VCC / 5 V
Linearity Error is calculated separately for the positive
(LinERRPOS) and negative (LinERRNEG) applied magnetic fields.
Linearity error is measured and defined as:
Note that clamping effect is applicable only when clamping is
enabled by programming of the device.
Allegro MicroSystems, LLC
115 Northeast Cutoff
40
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
CUSTOMER PACKAGE DRAWING
For Reference Only - Not for Tooling Use
(Reference DWG-9202)
Dimensions in millimeters - NOT TO SCALE
Dimensions exclusive of mold flash, gate burs, and dambar protrusions
Exact case and lead configuration at supplier discretion within limits shown
B
10°
+0.08
–0.05
+0.08
–0.05
1.00
5.21
E
2.60
F
Mold Ejector
Pin Indent
1.69
F
F
+0.08
–0.05
3.43
Branded
Face
1
2
3
4
0.89 MAX
0.54 REF
A
NNNN
YYWW
+0.08
–0.05
+0.08
–0.05
0.41
0.20
12.14 0.05
D
Standard Branding Reference View
1.27 NOM
N
Y
= Device part number
= Last two digits of year of manufacture
W = Week of manufacture
A
Dambar removal protrusion (16X)
Gate and tie burr area
0.54 REF
B
C
Branding scale and appearance at supplier discretion
0.89 MAX
D
E
F
Thermoplastic Molded Lead Bar for alignment during shipment
Active Area Depth, 0.37 mm REF
+0.08
1.50
–0.05
D
Hall element, not to scale
+0.08
–0.05
+0.08
–0.05
1.00
5.21
Figure 15: Package KT, 4-Pin SIP
Allegro MicroSystems, LLC
115 Northeast Cutoff
41
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Precision Programmable Linear Hall Effect Sensor IC
with EEPROM, Analog Output, and Advanced Output Linearization
A1340
Revision History
Revision
Revision Date
Description of Revision
–
1
2
September 16, 2014 Initial Release
December 2, 2014
February 12, 2015
Revised Selection Guide
Revised Package Drawing
Copyright ©2015, Allegro MicroSystems, LLC
Allegro MicroSystems, LLC reserves the right to make, from time to time, such departures from the detail specifications as may be required to
permit improvements in the performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that
the information being relied upon is current.
Allegro’s products are not to be used in 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, LLC assumes no responsibility for its
use; nor for any infringement of patents or other rights of third parties which may result from its use.
For the latest version of this document, visit our website:
www.allegromicro.com
Allegro MicroSystems, LLC
42
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
相关型号:
A1340LKTTN-4-T
High Precision Programmable Linear Hall Effect Sensor IC with EEPROM, Analog Output, and Advanced Output Linearization
ALLEGRO
A1351KKTTN-T
Hall Effect Sensor, 0.20-4.80V, BICMOS, Plastic/epoxy, Rectangular, 4 Pin, Through Hole Mount, LEAD FREE, PLASTIC, SIP-4
ALLEGRO
A1354KKT-T
High Precision 2-Wire Linear Hall Effect Sensor IC With Pulse Width Modulated Output
ALLEGRO
A1354KKTTN-T
High Precision 2-Wire Linear Hall Effect Sensor IC with Pulse Width Modulated Output
ALLEGRO
©2020 ICPDF网 联系我们和版权申明