A1341 Datasheet

A1341
High Precision, Programmable Linear Hall Effect Sensor IC with EEPROM,
SENT and PWM Output Protocols, and Advanced Output Linearization
FEATURES AND BENEFITS
• Advanced 32-segment output linearization functionality
enables high output accuracy and linearity in the
presence of non-linear input magnetic fields
• Selectable digital SENT (Single Edge Nibble
Transmission) or PWM (Pulse Width Modulation) output
• SENT output is SAEJ2716 JAN2010 compliant Allegro
Proprietary Enhanced Programmable Features
• Customer programmable sensitivity offset, bandwidth,
output polarity, output clamps, 1st and 2nd order temperature
compensation
• Simultaneous programming of all parameters for accurate
and efficient system optimization
• 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, overvoltage, and
undervoltage
• Wide ambient temperature range: –40°C to 150°C
• Operates with 4.5 to 5.5 V supply voltage
Package: 4-pin SIP (suffix KT)
1 mm case thickness
DESCRIPTION
The A1341 device is a high precision, programmable Hall
effect linear sensor integrated circuit (IC) with a configurable
pulse width modulated (PWM) or single edge nibble
transmission (SENT) output, for both automotive and nonautomotive applications. The signal path of the A1341 provides
flexibility through external programming that allows the
generation of an accurate, and customized output voltage from
a input magnetic signal. The A1341 provides 12 bits of output
resolution, and supports a maximum bandwidth of 3 kHz.
The BiCMOS, monolithic integrated circuit incorporates a
Hall sensor element, precision temperature-compensating
circuitry to reduce the intrinsic sensitivity and offset drift of the
Hall element, a small-signal high-gain amplifier, proprietary
dynamic offset cancellation circuits, and advanced output
linearization circuitry.
With on-board EEPROM and advanced signal processing
functions, the A1341 provides an unmatched level of customer
reprogrammable options for characteristics such as gain
and offset, bandwidth, output clamps, and output polarity.
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.
A key feature of the A1341 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.
The A1341 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
Signal
12-bit
Hall
Element
Factory Preset
Magnetic Range
and
Signal Offset
A to D
Conversion
Output
Bandwidth
and
Temperature
Compensation
Sensitivity
and
Fine Offset
Adjustment
Linearization
Clamps
Figure 1: A1341 Signal Processing Path
SENT/PWM
Output Driver
Functions with programmable parameters indicated by double-headed arrows.
A1341-DS
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
Selection Guide
Part Number
A1341LKTTN-T
Packing*
4000 pieces per 13-in. reel
*Contact Allegro™ for additional packing options
Table of Contents
Specifications
Absolute Maximum Ratings
Thermal Characteristics
Functional Block Diagram
Pin-out Diagram and Terminal List
Electrical Characteristics
Magnetic Characteristics
Programmable Characteristics
Characteristic Performance
Functional Description
3
3
3
4
4
5
6
7
9
12
Signal Processing Parameter Setting
12
Digital Signal Processing
13
Bandwidth Selection
13
Temperature Compensation
13
Sensitivity (Gain) Adjustment
15
Output Fine Offset Adjustment
15
Linearization of Output
15
Output Polarity
16
Output Clamps Setting
16
Output Protocol Selection
16
Protection Features
17
Operating Voltage and Low Voltage
Protection17
Open Circuit Detection
17
Typical Application
17
EEPROM Lock Features
18
Memory Locking Mechanisms
18
Programming Serial Interface
Transaction Types
Writing the Access Code
19
19
19
Writing to EEPROM Reading from EEPROM
Error Checking
Serial Interface Reference
Serial Interface Message Structure
19
20
20
21
22
Linear Output Protocols
27
EEPROM Structure
34
Definitions of Terms
49
Package Outline Drawing
51
PWM Output Mode
SENT Output Mode
Message Structure
Optional Serial Output Protocol
Data Nibble Format
Pause Pulse Timing Synchronization
EEPROM Customer-Programmable Parameter
Reference
27
28
28
29
29
29
36
Full Scale (FSI and FSO)
49
Power-On Time (tPO)49
Signal Propagation Delay (tPROP)49
Signal Response Time (tRESP)49
Quiescent Output (QOUT)
49
Quiescent Output Drift through Temperature
Range49
Sensitivity (Sens)
49
Sensitivity Drift through Temperature Range
50
Sensitivity Drift Due to Package Hysteresis
(ΔSensPKG)50
Linear Sensitivity Error
50
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
2
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
SPECIFICATIONS
Absolute Maximum Ratings
Rating
Unit
Forward Supply Voltage
Characteristic
Symbol
VCC
Notes
30
V
Reverse Supply Voltage
VRCC
–20
V
Forward Supply Current
ICC
30
mA
Reverse Supply Current
IRCC
–30
mA
Forward Output Voltage (OUT Pin)
VOUT
30
V
Reverse Output Voltage (OUT Pin)
VROUT
–0.5
V
ISINK
50
mA
EEPROMW(max)
100
cycle
–40 to 150
ºC
Forward Output Sink Current (OUT Pin)
Maximum Number of EEPROM Write
Cycles
Operating Ambient Temperature
TA
Maximum Junction Temperature
TJ(max)
165
ºC
Tstg
–65 to 165
ºC
Storage Temperature
L temperature range
Thermal Characteristics may require derating at maximum conditions, see application information
Characteristic
Symbol
Package Thermal Resistance
Test Conditions*
RθJA
1-layer PCB with copper limited to solder pads
Value
Unit
174
ºC/W
*Additional thermal information available on the Allegro website.
Power Dissipation versus Ambient Temperature
1100
Power Dissipation, PD (mW)
1000
900
800
1-layer PCB, 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
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
3
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
VCC
UVLO
OVLO
Analog
Regulator
POR
Factory Coarse Sensitivity
Factory
and Magnetic Range
Coarse Offset
Setting
Trim
Digital
Regulator
Clock
Generator
EEPROM
Analog
Front End
Digital
Subsystem
ADC
Hall
Element
Serial
Decode
Anti-Alias
Filter
Temperature
Sensor
ADC
Precision
Reference
A/D
12
12
Serial
Interface
Bandwidth
Select
Temperature
Compensation
HV Pulse
Master
Control
Digital
Sensitivity
and Offset Trim
Pulse
Detect
EEPROM
Control
Scan/
IDDQ
Linearization
Clamp
SENT/
PWM
Driver
OUT
GND
Functional Block Diagram
Terminal List Table
1
Number
Name
1
VCC
Input power supply, use bypass capacitor to connect to ground
Function
2
OUT
Output pin; EEPROM strobe input
3
NC
4
GND
Not connected; connect to GND for optimal ESD performance
Device ground
2 3 4
Pin-out Diagram
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
4
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
ELECTRICAL CHARACTERISTICS: valid through full operating temperature range, TA , and supply voltage, VCC ,
CBYPASS = 10 nF, unless otherwise specified
Characteristics
Symbol
Test Conditions
Min.
Typ.
Max.
Unit1
4.5
–
5.5
V
General Electrical Characteristics
Supply Voltage
VCC
Supply Current
ICC
Reverse Supply Current
IRCC
Supply Zener Clamp Voltage
Hall Chopping Frequency3
Low Voltage Detection Threshold
Power-On Reset
Overvoltage Lockout Threshold
SENT Message Duration3
Minimum Programmable SENT
Message Duration3
4
–
10
mA
VRCC = 20 V
–
–
–5
mA
ICC = ICC(max) + 3 mA, TA = 25°C
30
–
–
V
TA = 25°C
–
128
–
kHz
VCC(LVD)LOW LVD_DIS = 0
4.25
4.4
4.55
V
VCC(LVD)HIGH LVD_DIS = 0
4.35
4.5
4.7
V
PORLOW
3.5
3.7
4.1
V
PORHIGH
3.6
3.8
4.15
V
OVLO_LO = 1, TA = 25°C
5.6
–
–
V
OVLO_LO = 0, TA = 25°C
18
–
–
V
Tick time = 3 µs
–
–
1
ms
Tick time = 0.25 µs, 3 data nibbles of
information, nibble length = 27 ticks
–
41
–
µs
VSAT
VCC = 4.5 V, ISINK = 4.6 mA
–
0.3
0.45
V
VZSUPPLY
fC
VCC(OV)
tSENT
tSENTMIN
Output Electrical Characteristics
Output Saturation Voltage
Output Current Limit
ILIMIT
Output FET on, TA = 25°C
20
35
50
mA
Output Zener Clamp Voltage
VZOUT
TA = 25°C
30
–
–
V
Capacitance3,4
CLOAD
OUT to GND
–
–
10
nF
BW = 3000 Hz
–
0.5
–
ms
BW = 1500 Hz
–
0.8
–
ms
BW = 750 Hz
–
2
–
ms
BW = 375 Hz
–
3
–
ms
Output Load
Power-On
Time5,6
Signal Propagation Delay3,6
Full Scale Output Range3
tPO
tPROP
FSO
BW = 188 Hz
–
6
–
ms
BW = 3000 Hz
–
0.35
–
ms
BW = 1500 Hz
–
0.7
–
ms
BW = 750 Hz
–
1.4
–
ms
BW = 375 Hz
–
2.8
–
ms
BW = 188 Hz
–
5.6
–
ms
PWM_MODE = 1 (PWM mode), CLAMP_HIGH
= CLAMP_LOW = 0 (PWM duty cycle)
–
–
90
%D
PWM_MODE = 0 (SENT mode)
–
–
4095
LSB
11
G (gauss) = 0.1 mT (millitesla).
Protection Features section.
by design.
4Clarity 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.
5Parameter is verified by lab characterization with a limited amount of samples.
6See Definitions of Terms section.
2See
3Determined
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
5
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
MAGNETIC CHARACTERISTICS: valid through full operating temperature range, TA , and supply voltage, VCC , CBYPASS =
10 nF, unless otherwise specified
Characteristics
Symbol
Test Conditions
Factory Programmed Device Values (Before Customer
Magnetic Input Signal Range
BIN
Magnetic Input Signal Offset
BINOFFSET
Output Sensitivity
Sens
Quiescent Output
OUT(Q)
Programming)2,3,
Output Clamp
Sensitivity Drift Over Temperature4
Output Offset Drift Over Temperature5
DSens
DOUT(Q)
Max.
Unit1,2
–
±500
–
G
–
0
–
%FSI
SENS_COARSE = 0, SENS_MULT = 0
SIG_OFFSET = 0
0.097
0.1
0.103
%FSO/G
BIN = 0 G, TA = 25°C
49.4
50
50.5
%FSO
–
4095
–
LSB
94.8
95
95.2
%D
–
0
–
LSB
4.8
5
5.2
%D
TA = –40°C to 25°C
–
<±0.03
–
%/°C
TA = 25°C to 150°C
–
<±0.02
–
%/°C
TA = –40°C to 25°C
–
<±0.005
–
%/°C
TA = 25°C to 150°C
–
<±0.005
–
%/°C
PWM_MODE = 1 (PWM mode) (PWM duty
cycle)
PWM_MODE = 0 (SENT mode)
OUTCLP(L)
Typ.
VCC = 5 V, TA = 25°C
SENS_COARSE = 0
PWM_MODE = 0 (SENT mode)
OUTCLP(H)
Min.
PWM_MODE = 1 (PWM mode) (PWM duty
cycle)
11
G (gauss) = 0.1 mT (millitesla).
2FSO means Full Scale Output and FSI means Full Scale Input. See Definitions of Terms section.
3Device performance is optimized for the input magnetic range of SENS_COARSE = 0 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.
4Does not include drift over lifetime and package hysteresis.
5Offset 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
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
6
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
PROGRAMMABLE CHARACTERISTICS: valid through full operating temperature range, TA , and supply voltage, VCC ,
CBYPASS = 10 nF, unless otherwise specified
Characteristics
Internal Bandwidth
Symbol
Test Conditions
Min.
Typ.
Max.
Unit1
–
3
–
bit
188
–
3000
Hz
TA = 25°C, measured as a percentage of BW
–
±5
–
%
QOUT_FINE
–
12
–
bit
Programming2
Bandwidth Programming Bits
BW
Bandwidth Programming Range
TA = 25°C; for programming values, see BW in
EEPROM Structure section
Bandwidth Post-Programming
Tolerance
BW
∆BW
Fine Quiescent Output2
FIne Quiescent Output Programming
Bits
Fine Quiescent Output Programming
Range
QOUT_FINE TA = 25°C, BIN = 0 G
–49
–
49
%FSO
Fine Quiescent Output Programming
Step Size
StepQOUT_
TA = 25°C, BIN = 0 G
FINE
–
0.0244
–
%FSO
0.025
–
0.18
%FSO/G
–
12
–
bit
Output Sensitivity2
Output Sensitivity
SENS_OUT TA = 25°C
Sensitivity Multiplier Programming Bits
SENS_MULT
Sensitivity Multipler Programming
Range
SENS_MULT TA = 25°C
0
–
2
–
Sensitivity Multiplier Programming
Step Size
StepSENS_
TA = 25°C
MULT
–
0.00048
–
–
TA = 25°C
–
33
–
data
sampling
point
LIN_x, programmed with output fitting method
–
12
–
bit
Linearization2
Linearization Positions
Linearization Position Coefficient Bits
LINPOS_
COEFF
Output Polarity Bit
LIN_OUTPUT_INVERT
–
1
–
bit
Input Polarity Bit
LIN_INPUT_INVERT
–
1
–
bit
Temperature Compensation (TC)2
1st Order Sensitivity TC Programming
Bits
TC1_SENS_CLD, TA = –40°C
–
8
–
bit
TC1_SENS_HOT, TA = 150°C
–
8
–
bit
– 98
–
+291
m%/°C
–
1.53
–
m%/°C
TC2_SENS_CLD, TA = –40°C
–
9
–
bit
TC2_SENS_HOT, TA = 150°C
–
9
–
bit
TC1_SENS_
Typical 1st Order Sensitivity TC
Programming
Range3
1st Order Sensitivity TC Programming
Step Size3
2nd Order Sensitivity TC Programming
Bits
CLD
TC1_
SENS_
HOT
StepTC1SENS
Continued on the next page…
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
7
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
PROGRAMMABLE CHARACTERISTICS (continued): valid through full operating temperature range, TA , and supply volt-
age, VCC , CBYPASS = 10 nF, unless otherwise specified
Characteristics
Temperature Compensation
Symbol
(TC)2
Test Conditions
Min.
Typ.
Max.
Unit1
–1.53
–
1.53
m%/°C2
–
0.00596
–
m%/°C2
–
8
–
bit
−0.48
−
+0.48
G/°C
–
0.00381
–
G/°C
bit
(continued)
TC2_SENS_
Typical 2nd Order Sensitivity TC
Programming Range3,4
CLD
TC2_
SENS_
HOT
2nd Order Sensitivity TC Programming
StepTC2SENS
Step Size3,4
1st Order Magnetic Offset TC
Programming Bits
Typical 1st Order Magnetic Offset TC
Programming Range
1st Order Magnetic Offset TC
Step Size
TC1_OFFSET
TC1_OFFSET
SENS_COARSE = 0
StepTC1_
OFFSET
Output Clamping Range2
Clamp Programming Bits
Output Clamp Programming Range
Clamp Programming Step Size
CLAMP_HIGH
–
6
–
CLAMP_LOW
–
6
–
bit
50.78
–
100
%FSO
OUTCLP(H) TA = 25°C, VCC = 5 V
OUTCLP(L) TA = 25°C, VCC = 5 V
0
–
49.22
%FSO
StepCLP(H) TA = 25°C
–
0.78
–
%FSO
StepCLP(L) TA = 25°C
–
0.78
–
%FSO
Accuracy (After Customer Programming)
Linearity Sensitivity Error
LinERR
–
<±1
–
%
–
< ±1
–
%
Sensitivity Drift Due to Package
Hysteresis
∆SensPKG
Variation on final programmed Sensitivity value;
measured at TA = 25°C after temperature
cycling from 25°C to 150°C and back to 25°C
Sensitivity Drift Over Lifetime
∆SensLIFE
TA = 25°C, shift after AEC Q100 grade 0
qualification testing
–
±3
–
%
Quiescent Output Drift over Lifetime
DOUT(Q)LIFE
TA = 25°C, shift after AEC Q100 grade 0
qualification testing
–
<±1
–
%
SENT Characteristics2
VSENT(L)
SENT Output Signal
SENT Output Trigger Signal
VSENT(H)
10 kΩ ≤ Rpullup ≤ 50 kΩ
–
–
0.05
V
Minimum Rpullup = 10 kΩ
0.9 × VCC
–
–
V
Maximum Rpullup = 50 kΩ
0.7 × VCC
–
–
V
VSENTtrig(L)
–
–
1.2
V
VSENTtrig(H)
2.8
–
–
V
11
G (gauss) = 0.1 mT (millitesla).
by design.
unit m% = 0.001%; for example, 250 m%/°C = 0.025 %/°C = 2.5 × 10–3 /°C.
4The unit m% / C2 means: (10–3 × %) / C2.
2Determined
3The
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
8
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
CHARACTERISTIC PERFORMANCE
Average Supply Current (On) versus Temperature
9.0
9.0
8.6
8.6
8.2
TA (°C)
-40
7.8
-20
7.4
0
7.0
50
25
75
6.6
100
6.2
125
150
5.8
5.4
5.0
4.0
4.5
5.0
5.5
Supply Current, ICC(av) (mA)
Supply Current, ICC(av) (mA)
Average Supply Current (On) versus Supply Voltage
VCC (V)
8.2
4.5
7.8
5.0
7.4
5.5
7.0
6.6
6.2
5.8
5.4
5.0
-60
6.0
-40
-20
Supply Voltage, VCC (V)
Output Saturation Voltage versus
Average Supply Voltage
250
TA (°C)
-40
-20
200
0
25
50
150
75
100
125
100
150
50
4.5
5.0
5.5
IOUT = 0.45 mA
VCC (V)
4.5
5.0
5.5
-40
VCC (V)
5.2
4.5
5.0
5.0
4.8
5.5
4.6
Duty Cycle (%)
Duty Cycle (%)
95.6
5.4
40
60
80
100
120
140
160
140
160
4.5
5.0
94.8
5.5
94.6
94.2
120
VCC (V)
95.0
4.2
Ambient Temperature, TA (°C)
20
95.2
94.4
100
0
95.4
4.4
80
-20
Upper Clamp versus Average Temperature
5.6
60
160
Ambient Temperature, TA (°C)
95.8
40
140
50
5.8
20
120
100
96.0
0
100
150
6.0
-20
80
200
0
-60
6.0
Lower Clamp versus Average Temperature
-40
60
250
Supply Voltage, VCC (V)
4.0
-60
40
300
IOUT = 0.45 mA
0
4.0
20
Output Saturation Voltage versus
Average Temperature
Output Saturation Voltage,
VSAT (mV)
Output Saturation Voltage,
∆VOUT (mV)
300
0
Ambient Temperature, TA (°C)
94.0
-60
-40
-20
0
20
40
60
80
100
120
140
160
Ambient Temperature, TA (°C)
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
9
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
93.0
Average + 3 sigma
0.030
Sensitivity, Sens (m%D/G)
Sensitivity Drift, ∆Sens (%/°C)
0.040
Factory Programmed Sensitivity Drift
versus Ambient Temperature
0.020
Average
0.010
0
-0.010
Average – 3 sigma
-0.020
-0.030
-0.040
-80
∆TA relative to TA = 25°C
-60
-40
-20
0
20
40
60
80
100
120
92.0
91.0
Average + 3 sigma
89.0
Average – 3 sigma
88.0
-40
Factory Programmed Quiescent Voltage Output
Drift versus Ambient Temperature
40
60
80
100
120
140
160
50.40
0.002
QVO, VOUT(Q) (%D)
Average + 3 sigma
0.004
Average
-0
-0.002
-0.004
Average – 3 sigma
-0.006
50.30
50.20
50.10
Average
Average + 3 sigma
50.00
49.90
Average – 3 sigma
49.80
49.70
40.60
-60
-40
-20
0
20
40
60
80
100
120
49.50
-60
140
-40
-20
Change in Ambient Temperature, ∆TA (°C)
2.0
2.0
Linearity (%)
3.0
Average + 3 sigma
Average
0
-1.0
20
40
60
80
100
120
140
160
Negative Linearity versus Ambient Temperature
3.0
1.0
0
Ambient Temperature, TA (°C)
Positive Linearity versus Ambient Temperature
Linearity (%)
20
50.50
0.006
Average – 3 sigma
-2.0
-3.0
-60
0
Factory Programmed Quiescent Voltage Output
versus Ambient Temperature
0.008
QVO (m%/°C)
-20
Ambient Temperature, TA (°C)
Change in Ambient Temperature, ∆TA (°C)
-0.008
-80
Average
90.0
87.0
-60
140
Factory Programmed Sensitivity
versus Ambient Temperature
Average + 3 sigma
1.0
Average
0
Average – 3 sigma
-1.0
-2.0
-40
-20
0
20
40
60
80
100
Ambient Temperature, TA (°C)
120
140
160
-3.0
-60
-40
-20
0
20
40
60
80
100
120
140
160
Ambient Temperature, TA (°C)
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10
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
100
Quiescent Output Duty Cycle
QDCDC (%)
QOUT_FINE Step Size
Duty Cycle (%)
0.025
Quiescent Output Duty Cycle versus QOUT_FINE Code
versus Ambient Temperature
QOUT_FINE Step Size Duty Cycle
versus Ambient Temperature
Average + 3 sigma
Average
Average – 3 sigma
0.024
0.023
0.022
0.021
0.020
0.019
-60
-40
-20
0
20
40
60
80
100
120
140
90
Code 2048
80
70
Code 1024
60
50
Code 0
40
30
20
Code 3072
10
Code 4096
0
-60
160
-40
-20
Ambient Temperature, ∆TA (°C)
50.30
Duty Cycle (%)
0.76
Average
Average + 3 sigma
0.70
Average – 3 sigma
0.68
0.66
0
20
40
60
80
100
140
160
120
140
SENS_MULT Minimum
SENS_MULT Code 0
SENS_MULT Maximum
49.80
49.50
-60
160
-40
-20
0
20
40
60
80
100
120
140
160
Ambient Temperature, TA (°C)
Ambient Temperature, TA (°C)
2.50
120
49.90
46.60
-20
100
50.00
49.70
-40
80
50.10
0.62
0.60
-60
60
50.20
0.64
Sensitivity Multiplication Factor
versus Ambient Temperature
SENSDC Maximum Multiplier
2.00
SENS_MULT
Clamp Step Size
Duty Cycle (%)
50.40
0.72
40
50.50
0.78
0.74
20
Quiescent Output Duty Cycle versus
SENS_MULT Code versus Ambient Temperature
Clamp Step Size Duty Cycle
versus Ambient Temperature
0.80
0
Ambient Temperature, ∆TA (°C)
1.50
1.00
0.50
SENSDC Minimum Multiplier
0
-0.50
-60
-40
-20
0
20
40
60
80
100
120
140
160
Ambient Temperature, TA (°C)
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115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
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11
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
FUNCTIONAL DESCRIPTION
This section provides descriptions of the operating features
and subsystems of the A1341. For more information on specific terms, refer to the Definitions of Terms section. Tables of
EEPROM parameter values are provided in the EEPROM Structure section.
YAD is the output of the analog subsystem to the A-to-D converter,
Signal Processing Parameter Setting
BIN is the current magnetic input signal,
The A1341 has customer-programmable parameters that allow
the user to optimize the signal processing performed by the
A1341. 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.
SIG_OFFSET the factory-set signal offset, and
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 (%FSO) = SENS_COARSE (%FSO/G) × BIN
+ SIG_OFFSET (%FSI)
+ QOUT (%FSO)
(1)
where:
SENS_COARSE is the factory-set coarse sensitivity,
QOUT is the quiescent voltage output with no factory compensation.
The DSP stage provides customer-programmable sensitivity
(gain) fine offset adjusting, TC processing, bandwidth, clamp,
and linearization selection.
Output is a digital voltage signal, proportional to the applied
magnetic signal, with customer-selectable formatting: either
pulse-wave modulated (PWM) or in the single edge nibble transmission encoding scheme (SENT). The Full Scale Output range
is proportional to the Full Scale Input range, but is optimized by
customer-programmed parameters.
Signal
Factory
Programmed
Magnetic
Input Range/
Coarse
Sensitivity
Factory
Programmed
Signal Offset
Signal Input
to
A/D
Signal Input
to
Figure 2: Signal Path for Analog Subsystem
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12
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
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.
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
EEPROM. The values chosen for BW and RANGE affect the
DSP stage output resolution and the Signal Response Time,
tRESP . These tradeoffs are represented in the Electrical Characteristics table, above.
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.
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 Figure 4). It can be programmed using the TC1_OFFSET parameter
Table 1: Bandwidth-Related Tradeoffs
TEMPERATURE COMPENSATION
Bandwidth Selection
[Internal Update Rate]
(kHz)
DSP Output Resolution
(bit)
Other
11 to 12
3.000 [16.0]
10 to 11
The magnetic properties of materials can be affected by changes
in temperature, even within the rated ambient operating temperature range, TA . Any change in the magnetic circuit due to temperature variation causes a proportional change in the device output.
Sensitivity
Multiplier
/Fine QOUT
Adjustment
TC Codes
Applied for
TA = 25°C
Output
Sensitivity
and Offset
Applied
Linearization
Linearization
Coefficients
Applied
Clamps
Are Set
Figure 3: Signal path for digital subsystem
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115 Northeast Cutoff
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13
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
TA Range
< 25°C
> 25°C
1st Order
TC1_SENS_CLD
TC1_SENS_HOT
2nd Order
TC2_SENS_CLD
TC2_SENS_HOT
TC
25°C
1_S
EN
S_C
LD
Ma
TC1_SENS_CLD Code 0
TC1_S
EN
xC
D Min
S_CL
TC
ode
1_S
EN
S_
H
M
OT
Co
ax
de
TC1_SENS_HOT Code 0
Code
TC1_S
ENS_H
OT Min
Code
TA
EN
25°C
S_
CL
TC2_SENS_CLD Code 0
NS
DM
_C
LD
_H
E NS
ax C od e
T C 2 _S
o de
Mi n C
T C2 _ S E
OT
x
Ma
TC2_SENS_HOT Code 0
NS _
HO
TM
in
C
e
SENS_COARSE_COEF = SENS_COARSE(code 0) /
SENS_COARSE(factory code) (sets the factory-programmed sensitivity of the YAD function).
FFS
od
SIG_OFFSET (set to 0) is the factory programmed addition to the
magnetic offset parameter (sets the centerpoint of YAD ), and
1_O
Table 2: Sensitivity Temperature Compensation options
_S
ΔTA is the change in ambient temperature from 25°C (for example: at 150°C, ΔTA = 150°C – 25°C = 125°C, or at –40°C,
ΔTA = –40°C – 25°C = –65°C),
TC
e
e
TA
Figure 4: The 1st Order Magnetic Offset Temperature
Compensation Coefficient (TC1_OFFSET) is used for
linear adjustment of device output for temperature
changes.
T C2
TC2_SENS is the second-order coefficient: either TC2_SENS_
HOT or TC2_SENS_CLD depending on TA ,
TC1_OFFSET Code 0
Cod
Cod
e
TC1_SENS is the first-order coefficient: either TC1_SENS_HOT
or TC1_SENS_CLD depending on TA ,
Min
ax
od
YAD is the input from the analog subsystem via the A-to-D converter,
ET
M
ET
C
where:
FFS
SE
YTC (%FSO) = YAD (%FSO) + [ (TC1_SENS (m%/°C)
× ΔTA (°C)) + (TC2_SENS (m%/°C2) × ΔTA2 (°C)) ]
× ( YAD (%FSO) – SIG_OFFSET (%FSI) )
+ TC1_OFFSET (G/°C) × 0.09 (%FSO/G)
× SENS_COARSE_COEF × ΔTA (°C)
(2)
1_O
2_
The programmed values set the temperature compensation, YTC,
according to the following formula:
TC
TC
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 A1341 applies the first-order, and then the
second-order algorithm during this stage.
QOUT
TC1_SENS(m%/C2)
Sensitivity drift compensation is customer-programmed
(described below), within a framework of programmed temperature compensation. Optional temperature compensation for Sensitivity 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 coefficients are programmed separately for temperatures above 25°C
and below 25°C, as shown in Table 2. The resulting functions are
illustrated in Figure 5.
TC1_SENS(m%/C2)
in a range of ±0.48 G/°C . This compensation is applied in DSP,
after bandwidth selection.
TC1_OFFSET (G/°C)
A1341
TA
Figure 5: Sensitivity TC Functions
(upper) first order, (lower) second order
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14
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
SENSITIVITY (GAIN) ADJUSTMENT
LINEARIZATION OF OUTPUT
Sensitivity is applied in the DSP subsystem, after bandwidth
selection and temperature compensation. 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.
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 6. The A1341 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.
OUTOUT FINE OFFSET ADJUSTMENT
The Fine Offset adjustment is the segment of the DSP signal used
to trim the device output, OUT (%FSO).
QOUT_FINE is a customer-programmable parameter that sets the
Quiescent Output, QOUT , 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:
YDA (%FSO) = SENS_MULT × YTC (%FSO)
+ QOUT_FINE (%FSO)
(3)
SENS_OUT (%FSO/G) = SENS_MULT
× SENS (%FSO/G)
(4)
where SENS_MULT is the multiplication factor from 0 to 2.
Device Output (%)
QOUT_FINE is set as a percentage of OUT . It can be set to add
up to 50% of FSO to the output of the DSP stage, or subtract up
to 50% of FSO from the DSP output.
100
90
80
70
60
50
40
30
20
10
0
-4
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 A1341, 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. When the A1341 is in
operation, it applies a built-in algorithm to linearize output based
on the stored coefficients.
Each of the coefficient values can be individually overwritten
during normal operation. Figure 7 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 A1341 is in operation, it applies a linearization curve
built from the 33 coefficients provided by the user. For example,
Initial Output
Linearized Output
-3
-2
-1
0
1
2
3
4
Ring Magnet Rotation (°)
Figure 6: Example of Linearization of a Sinusoidal Magnetic Signal Generated by a Rotating Ring Magnet
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15
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
at position 5 the device originally would output 384 LSB of
magnetic field. This 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
Device Output Polarity can be changed using the
LIN_OUTPUT_INVERT bit set to 1. 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
(linearization table coefficients are decimal values from 0 to 4096
with steps of 128 codes) 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.
OUTPUT CLAMPS SETTING
To eliminate the effects of outlier points, the A1341 Clamp
Range, OUTCLP , is initially set to 100% of FSO for high clamp
and 0% of FSO for low clamp, and can be adjusted using the
CLAMP_HIGH and CLAMP_LOW parameters.
OUTPUT PROTOCOL SELECTION
The A1341 supports a linear voltage output in either PWM or
SENT format. The PWM_MODE parameter in EEPROM sets the
format. (Output format programming is described in the Linear
Output Protocols section.)
4096
3968
3840
3712
3584
3456
Output Signal
3328
3200
Device Digital Output (LSBs)
3072
Input Signal
2944
Linearization
Function
2816
2688
2560
2432
2304
2176
2048
1920
1792
1664
(2) Rescaled x = 3.2,
yields LSB = 570
1536
1408
1280
1152
1024
896
768
640
(3) Final result is LSB = 570 for the input point 5
512
384
256
(1) x at 5, preprocessing LSB = 384
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 7: Sample of Linearization Function Transfer Characteristic.
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16
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
Protection Features
OPEN CIRCUIT DETECTION
Lockout and clamping features protect the A1341 internal circuitry and prevent spurious output when supply voltage is out of
specification. Open circuit detection is also provided.
Diagnostic circuitry reuses the output pin (OUT) to provide
feedback to the external controller. A sense resistor, ROCD , can be
placed between OUT and a separate VBAT reference, as shown in
Table 3.
OPERATING VOLTAGE AND LOW VOLTAGE DETECTION
Typical Application
Supply voltage detection features protect the A1341 internal
circuitry and prevent spurious output when VCC is out of specification. Diagnostic circuitry reuses the output pin (OUT) to
provide feedback to the external controller. The A1341 provides
protection for both overvoltage and undervoltage on the supply
line. The A1341 has two active circuits to identify when the supply voltage is below the minimum operating level. The internal
power-on reset circuitry, POR, controls when an internal reset is
triggered. If the supply voltage drops below PORLOW , an internal
reset occurs and the output is forced to a high impedance state.
When the supply voltage rises above PORHIGH , the device comes
out of reset and the output response is dependent on the Low
Voltage Detection feature.
The Low Voltage Detection, LVD, feature provides feedback to
the external controller when VCC is below minimum operating
level, but above the POR threshold. This feature is enabled by
default and is disabled by setting LVD_DIS to logic 1. When
configured for SENT output, if the supply voltage drops below
VCC(LVD)LOW , a status bit is set in the SENT message to indicate
a low supply voltage condition. When configured for PWM output, if the supply voltage drops below VCC(LVD)LOW , the output
is forced to a Logic low state. As the supply voltage rises above
VCC(LVD)HIGH , the output returns to normal operating state.
The Overvoltage Lockout Threshold, VCC(OV) , is customer
programmable to either 6.5 or 19.3 V typical, by setting the
OVLO_LO parameter. By default, the part will produce an error
at the output if VCC > 19.3 V. Setting OVLO_LO = 1 changes this
condition to VCC > 6.5 V. When OVLO_LO = 1, using programming pulses higher than VCC will cause the part to enter in and
out of overvoltage lockout mode, causing intermittent errors at
the output. This behavior is not fatal, but the output is not valid.
If overvoltage conditions are reached, the PWM output will be
brought to GND or the SENT_STATUS bits will be set to indicate the condition.
Multiple A1341 linear devices can be connected to the external
controller as shown in Figure 8. However, EEPROM programming in the A1341 occurs when the external control unit excites
the A1341 OUT pin by EEPROM pulses generated by the ECU.
Whichever A1341s are excited by EEPROM pulses on their OUT
pin will accept commands from the controller.
Table 3: Open Circuit Diagnostic Truth Table
Node A
Node B
Node C
OUT State
Open
Closed
Closed
Closed
0 V to VBAT
Open
Closed
GND/Float
Open
Open
Closed
GND/Float
Open
Closed
Open
VBAT
Closed
Open
Open
VCC
Closed
Closed
Open
VCC to VBAT
VBAT Referenced
VCC
A
VCC
A1341
VBAT
B
ROCD
OUT
GND
C
ECU
VCC1
R PULLUP1
VCC
0.01 µF
A1341
OUT1
VOUT
GND
VCC2
R PULLUP2
VCC
0.01 µF
A1341
VOUT
OUT2
GND
Figure 8: Typical Application
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115 Northeast Cutoff
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17
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
EEPROM Lock Features
MEMORY LOCKING MECHANISMS
The A1341 is equipped with two distinct memory locking mechanisms:
Default Lock
At power up, all registers of the A1341 are locked by default.
EEPROM and volatile memory cannot be read or written. To
disable Default Lock, a very specific 30-bit customer access code
is written to address 0x24 in less than 70 ms from power-up;
see Write Access code. After this, device registers are accessible
through the programming interface. If VCC is power cycled, the
Default Lock automatically reenables. This ensures that during
normal operation, memory content will not be altered due to
unwanted glitches on VCC or the output pin.
Lock Bit
This is used after EEPROM parameters are programmed by the
customer. The customer programmable EELOCK feature disables
the ability to write to any EEPROM register. This feature takes
effect after writing the EELOCK bit and resetting power to the
device. This prevents the ability to disable Default Lock using the
method described above. Please note that after EELOCK bit is set
and VCC pin power cycled, the customer will not have the ability
to clear the EELOCK bit or to write any register. Customer will
still have ability to read any EEPROM register.
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115 Northeast Cutoff
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18
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
PROGRAMMING SERIAL INTERFACE
The A1341 incorporates a serial interface that allows an external
controller to read and write registers in the A1341 EEPROM and
volatile memory. The A1341 uses a point-to-point communication
protocol, based on Manchester encoding per G. E. Thomas (a rising edge indicates 0 and a falling edge indicates 1), with address
and data transmitted MSB first.
Transaction Types
Each transaction is initiated by a command from the controller;
the A1341 does not initiate any transactions. Two commands are
recognized by the A1341: Write and Read. There also are three
special function Write commands: Write Access Code, Write Disable Output, and Write Enable Output. One response frame type
is generated by the A1341, Read Acknowledge.
If the command is Read, the A1341 responds by transmitting the
requested data in a Read Acknowledge frame. If the command is
any other type, the A1341 does not acknowledge.
As shown in Figure 9, The A1341 receives all commands via the
VCC pin. It responds to Read commands via the OUT pin. This
implementation of Manchester encoding requires the communication pulses be within a high (VMAN(H)) and low (VMAN(L))
range of voltages for the VCC line and the OUT line. The Write
command pulses to EEPROM are supported by two high voltage
pulses on the OUT line.
Writing the Access Code
If the external controller will write to or read from the A1341
memory during the current session, it must establish serial communication with the A1341 by sending a Write command including the Access Code within 70 ms after powering up the A1341. If
this deadline is missed, all write and read access is disabled until
the next power-up.
Writing to 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-separated, long high-voltage strobes via the OUT pin. These strobes
are detected internally, allowing the A1341 to boost the voltage
on the EEPROM gates.
The required sequence is shown in Figure 10.
Write/Read Command –
Manchester Code
ECU
High Voltage pulses to
activate EEPROM cells
VCC
A1341
GND
OUT
Read Acknowledge
– Manchester Code
Figure 9: Top-level Programming Interface
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115 Northeast Cutoff
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19
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
Reading from EEPROM
A Read command with the register number is sent from the controller to the A1341. The device responds with a Read Acknowledge frame. Output is automatically disabled after the Read command from the controller is received and output is enabled after a
Read Acknowledge command is sent.
C0
C1
Input Data
C2
Error Checking
The serial interface uses a cyclic redundancy check (CRC) for
data-bit error checking (synchronization bits are ignored during
the check).
1x 0
1x 1
0x 2
1x 3
= x3 + x + 1
Figure 11: CRC Calculation
The CRC algorithm is based on the polynomial
g(x) = x3 + x + 1 ,
and the calculation is represented graphically in Figure 11.
The trailing 3 bits of a message frame comprise the CRC token.
The CRC is initialized at 111.
VCC
Write Access
Command
Write
Command
EEPROM
Programming
Pulses
Write to
EEPROM
VOUT
Write
Command
tWRITE(E)
High
Impedance
Normal Operation
Normal Operation
GND
<70 ms from power-on
VCC
Read from
EEPROM
tsPULSE(E)
tWOUT_DIS
t
tWOUT_EN
Read
Command
Write Access
Command
<70 ms from power-on
VOUT
Read
Acknowledge
Normal Operation
Normal Operation
GND
tSTART_READ
tROUT_LOW
t
tROUT_EN
Figure 10: Programming Read and Write Timing Diagrams
(see Serial Interface Reference section for definitions)
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115 Northeast Cutoff
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20
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
Serial Interface Reference
Table 4. Serial Interface Protocol Characteristics1
Characteristics
Symbol
Note
Min.
Typ.
Max.
Unit
Customer Access Code should be fully entered
in less than tACC , measured from when VCC
crosses VCC(UV_high).
–
–
70
ms
Defined by the input message bit rate sent from
the external controller
4
–
100
kbps
Input/Output Signal Timing
Access code Time Out
tacc
Bit Rate
Bit Time
Bit Time Error
tBIT
errTBIT
Data bit pulse width at 4 kbps
243
250
257
µs
Data bit pulse width at 100 kbps
9.5
10
10.5
µs
Deviation in tBIT during one command frame
–11
–
+11
%
–
9 µs –
0.25 × tBIT
60
µs
2 × tBIT
–
–
µs
Write Output Disable Delay
tWOUT_DIS
Required delay from the trailing edge of certain
Write command frames to output entering the
high impedance state
Write Delay
tWRITE(E)
Required delay from the trailing edge of the
second EEPROM Programming pulse to the
leading edge of a following command frame
Write Output Enable Delay
tWOUT_EN
Delay from the trailing edge of the final
EEPROM programming pulse to output entering
the normal operation state
–
6
60
µs
Read Acknowledge Delay
tREAD
Required delay from the trailing edge of a Read
Acknowledge frame to the leading edge of a
following command frame
2 × tBIT
–
–
µs
–
45
60
µs
25 µs –
0.25 × tBIT
50 µs –
0.25 × tBIT
150 µs –
0.25 × tBIT
µs
Time the output is pulled low by device before
Read Acknowledge message
Read Output Disable Delay
tROUT_LOW
Read Delay2
Delay from the trailing edge of a Read
tSTART_READ command frame to the leading edge of the Read
Acknowledge frame
Read Output Enable Delay
tROUT_EN
Required delay from the trailing edge of the final
Read Acknowledge pulse to output entering the
normal operation state
–
45
60
µs
Disable Output Delay2
tDIS_OUT
Delay from the trailing edge of a Disable Output
command frame to the device output going from
normal operation to the high impedance state
1 µs –
0.25 × tBIT
5 µs –
0.25 × tBIT
15 µs –
0.25 × tBIT
µs
Enable Output Delay2
tENB_OUT
Delay from the trailing edge of an Enable Output
command frame to the device output going from
the high impedance state to normal operation
1 µs –
0.25 × tBIT
5 µs –
0.25 × tBIT
15 µs –
0.25 × tBIT
µs
tsPULSE(E)
Delay from last edge of write command to start
of EEPROM programming pulse
40
–
–
μs
Applied to VCC line
7.3
–
–
V
Read from OUT line
VCC – 0.2
–
–
V
EEPROM Programming Pulse
EEPROM Programming Pulse
Setup Time
Input/Output Signal Voltage
Manchester Code High Voltage
VMAN(H)
Manchester Code Low Voltage
VMAN(L)
Applied to VCC line
–
–
5.7
V
Read from OUT line
–
–
VSAT
V
1Determined
by design.
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.
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High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
Serial Interface Message Structure
The general format of a command message frame is shown in
Figure 12. 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.
The bits are described in Table 5.
Read/Write
Synchronize
0
Memory Address
Data
0 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1
MSB
0 0 1 1 0
...
CRC
0/1 0/1 0/1 0/1
MSB
Manchester Code per G. E. Thomas
Bit boundaries
Figure 12: General Format for Serial Interface Commands
Table 5: Serial Interface Command General Format
Bits
Parameter Name
Values
2
Synchronization
00
Used to identify the beginning of a serial interface command
0
[As required] Write operation
1
[As required] Read operation
1
Read/Write
Description
6
Address
0/1
[Read/Write] Register address (volatile memory or EEPROM)
Variable
Data
0/1
[As required] variable length, for data
3
CRC
0/1
Incorrect value indicates errors
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A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
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.
Table 6: Read
Function
Provides the address in A1341 memory to be accessed to transmit the contents to the external controller in the next
Read Acknowledge command.
A timely Write Access Code command is required once, at power-up of the A1341.
Syntax
Sent by the external controller on the A1341 VCC pin.
Related Commands
Read Acknowledge
Read/Write
Pulse Sequence
Synchronize
0
0
Memory Address
CRC
1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1
MSB
Options
None
Examples
Address in non-volatile memory: 0XXXXX
Address in volatile memory: 100100 (Register 0x24)
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A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
Table 7: Read Acknowledge
Function
Transmits to the external controller data retrieved from the A1341 memory in response to the most recent Read
command.
Syntax
Sent by the A1341 on the A1341 OUT pin.
Sent after a Read command.
Related Commands
Read
Data
(30 bits)
Synchronize
Pulse Sequence
0
CRC
0/1 0/1 0/1 0/1 . . . 0/1 0/1 0/1 0/1 0/1
0
MSB
Options
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.
Examples
–
Table 8: Write
Function
Transmits to the A1341 data prepared by the external controller.
Syntax
Sent by the external controller on the A1341 VCC pin.
A timely Write Access Code command is required once, at power-up of the A1341.
For writing to non-volatile memory.
Related Commands
Disable Output, Enable Output, Write Access Code
Read/Write
Synchronize
Pulse Sequence
0
0
Data
(30 bits)
Memory Address
0 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 . . .
MSB
CRC
0/1 0/1 0/1 0/1
MSB
Options
–
Examples
Address in non-volatile memory: 0XXXXX
Address in volatile memory: 100100 (Register 0x24)
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A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
Table 9: Write Access Code
Function
Transmits the Access Code to the A1341; data prepared by the external controller, but must match the internal 30-bit
code in the A1341 memory.
Syntax
Sent by the external controller on the A1341 VCC pin.
Sent within 70 ms of A1341 power-on, and before any other command.
Related Commands
Read/Write
Pulse Sequence
0
0
Data
(30 bits)
Memory Address
Synchronize
0
1
0
0
1
0
0
MSB
1
0
CRC
0 ...
1
0
0
1
MSB
Options
None
Examples
Standard Customer Access Code: 0x2781_1F77 to address 0x24
Table 10: Write Disable Output
Function
Places OUT in a high impedance state. It is not required, but it can be used to disable normal output for longer time
than the time that device applies to disable the output after a Read command from the controller.
Syntax
Sent by the external controller on the A1341 VCC pin.
For writing to non-volatile memory.
Related Commands
Write Enable Output
Read/Write
Pulse Sequence
0
0
Data
(30 bits)
Memory Address
Synchronize
0
1
MSB
Options
None
Examples
0x10 to address 0x24
0
0
1
0
0
0 ...
0
1
CRC
0
0
0
0
0
1
0
MSB
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A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
Table 11: Write Enable Output
Function
Restores normal output from the OUT pin after a high impedance state has been imposed by a Disable Output
command.
Syntax
Sent by the external controller on the A1341 VCC pin.
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
Pulse Sequence
0
0
Data
(30 bits)
Memory Address
Synchronize
0
1
MSB
Options
None
Examples
0x0 to address 0x24
0
0
1
0
0
0 ...
0
0
CRC
0
0
0
0
0
1
1
MSB
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A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
LINEAR OUTPUT PROTOCOLS
The operating output of the A1341 is digital voltage signal that
transfers information proportionally to the applied magnetic input
signal. Two customer-selectable options are provided for output
signal formatting: pulse-wave modulated (PWM), and single
edge nibble transmission encoding scheme (SENT, SAEJ2716).
direct proportion to the applied magnetic field.
The PWM output mode is configured by setting the following
parameters in EEPROM:
• PWM_MODE set to 1 to select the PWM option (for programming parameters, see EEPROM Structure section)
PWM Output Mode
• FPWM sets the PWM carrier frequency
PWM involves converting the output voltage amplitude to a
series of constant-frequency binary pulses, with the percentage of
the of high portion of the pulse varied in direct proportion to the
D = 5%
D = 50%
D = 95%
CLAMP_HIGH
Magnetic Signal,
BIN (G)
PWM Waveform (V)
• CALIBRATE_PWM parameter can be set to enable calibration
of the output 50% duty cycle level at power-on
CLAMP_LOW
D0T
D1T
D2T
D3T
D4T
D5T
D6T
D7T
D8T
D9T
D10T
D(x) = tpulse(x) / Tperiod
tpulse(5)
Tperiod
0T
1T
2T
3T
4T
5T
6T
7T
8T
9T
10T
11T
Time
Figure 13: PWM Mode
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High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
SENT Output Mode
boundary for the nibble; to assign the delimiting state, select a
fixed duration for the interval (the SENT_LOVAR parameter
selects the interval, and SENT_FIXED sets the duration)
The SENT output mode converts the input magnetic signal to a
binary value mapped to the Full Scale Output, FSO, range of 0
to 4095, shown in Figure 14. This data is inserted into a binary
pulse message, referred to as a frame, that conforms to the SENT
data transmission specification (SAEJ2716 JAN2010). Certain
parameters for configuration of the SENT messages can be set in
EEPROM.
• The other interval in the pair becomes the information state and
is variable in duration in order to contain the data payload of the
nibble
The duration of a nibble is denominated in clock ticks. The period
of a tick is set by dividing a 4-MHz clock by the value of the
SENT_TICK parameter. The duration of the nibble is the sum of
the low-voltage interval plus the high-voltage interval.
The SENT output mode is configured by setting the following
parameters in EEPROM:
The nibbles of a SENT message are arranged in the following
required sequence (see Figure 15):
• PWM_MODE set to 0 (default) to select the SENT option
• SENT_x programming parameters (see EEPROM Structure
section)
1. Synchronization and Calibration: flags the start of the SENT
message
MESSAGE STRUCTURE
2. Status and Communication: provides A1341 status and the
format of the data
A SENT message is a series of nibbles, with the following characteristics:
3. Data: magnetic field and optional data
• Each nibble is an ordered pair of a low-voltage interval followed by a high-voltage interval
4. CRC: error checking
5. Pause Pulse (optional): sets timing relative to A1341 updates
• Either interval can be the delimiting state, which only sets a
Magnetic Signal,
BIN (G)
4095 (1111 1111 1111 1111)
2048 (1000 0000 0000 0000)
0000 (0000 0000 0000 0000)
SENT Data Value
(LSB)
A1341
Figure 14: SENT Mode Outputs a Digital Value that can be Read by the External Controller
SENT_FIXED
SENT_FIXED
SENT_FIXED
SENT_FIXED
SENT_FIXED
SENT_FIXED
SENT_LOVAR = 0
12 to 27
ticks
56 ticks
Nibble Name
Synchronization
and Calibration
56 ticks
SENT_LOVAR = 1
12 to 27
ticks
12 to 27
ticks
12 to 27
ticks
Data 1
(MSB)
Data 6
CRC
12 to 27
ticks
12 to 27
ticks
12 to 27
ticks
Status and
Communication
12 to 27
ticks
SENT_FIXED
SENT_FIXED
SENT_FIXED
SENT_FIXED
Pause
Pulse
(optional)
SENT_FIXED
SENT_FIXED
tSENT
Figure 15: General Format for SENT Message Frame
(upper panel) low state fixed, (lower panel) high state fixed
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A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
OPTIONAL SERIAL OUTPUT PROTOCOL
DATA NIBBLE FORMAT
In the Status and Communication section, the data format selection can be:
When transmitting normal operation data, information about the
magnetic field is embedded in the first three Data nibbles. Each
Data nibble consists of 4 bits with values ranging from 0 to 15.
In order to present an output with the resolution of 12 bits, 3 Data
nibbles are required. The Data nibble containing the MSB of the
whole Data section is sent first.
• Normal device output (voltage proportional to applied
magnetic field) in SENT protocol (SENT_SERIAL = 0).
• Augmented data on the magnetic parameters and
device settings, in an optional Serial Output protocol
(SENT_SERIAL = 1, 2, or 3). Any of these three protocols
enables transmission of values from the following EEPROM
parameters, in the following order:
Table 12: Serial Output Protocols
Message ID
(4 or 8 bits)
Data
(8, 12, or 16 bits)
0
Corrected temperature
1
SENS_COARSE
1
SIG_OFFSET
3
QOUT_FINE
4
SENS_MULT
5
CLAMP_HIGH
6
CLAMP_LOW
7
DEVICE_ID (always 134110)
□□ Additional Short serial protocol (SENT_SERIAL = 1).
Has a message payload of 12 bits: 8 bits are for value data,
and 4 bits for the message ID (identification). A total of 16
separate SENT messages are required to transmit the entire
data group.
□□ Additional Enhanced 16-bit serial protocol (SENT_SERIAL
= 2). Has 12 bits for value data, and 4 bits for the message
ID. A total of 18 SENT messages are required to transmit
the entire data group.
□□ Additional Enhanced 24-bit serial protocol (SENT_SERIAL
= 3). Has 16 bits for value data, and 8 bits for the message
ID. A total of 18 SENT messages are required to transmit
the entire data group.
Three additional optional Data nibbles can be associated with
other parameters, by setting the parameter SENT_DATA:
• Counter – Each message frame has a serial number in each
Counter nibble
• Temperature – Temperature data from the A1341 internal
temperature sensor, in two’s complement format, with MSB
first:
□□ All zeros = 25°C
□□ Always is 0.8 LSB/°C except for serial output protocol
□□ For serial output protocol, temperature slope = 0.5 LSB/°C.
• Inverted – The last nibble in the message frame is the first
nibble, inverted (as an additional error check)
PAUSE PULSE TIMING SYNCHRONIZATION
In the Pause Pulse section, additional time can be added at the
end of a SENT message frame to ensure all message frames are
of equal length. The SENT_UPDATE parameter selects one of
these options:
• Allow message frame duration to vary according to the
contents; no Pause pulse is applied. (SENT_UPDATE = 0)
• The device sends messages with constant duration. If a
particular message is shorter, a Pause pulse is inserted with a
length that completes the message period. (SENT_UPDATE
= 1)
• Synchronize the message frame transmission rate with the
A1341 internal update rate (set by BW value) by inserting a
calculated Pause pulse to complete required period. (SENT_
UPDATE = 2)
Figures 16, 17, and 18 show examples of the timing relationship
between SENT message Pause pulse configurations and the internal update rate of the A1341.
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High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
n+1
n+2
n+3
n+4
SENT message 2
SENT message 3
data
stat
(skipped)
sync
stat
sync
CRC
data
stat
sync
CRC
data
stat
sync
SENT message 1
n+6
(skipped)
(skipped)
SENT
message
n+5
CRC
n
internal
update
data
A1341
SENT message 4
Figure 16: Messages Do not Contain a Pause Pulse (SENT_UPDATE = 0)
Messages do not contain a Pause pulse (SENT_UPDATE = 0), so the SENT message frame rate is not constant. The value transmitted in a
message is taken from the last internal update ready before the first Data nibble of the message is composed. Therefore, individual internal
updates may be skipped or repeated, depending on the BW bandwidth and SENT_TICK time settings.
SENT
message
SENT message 1
SENT message 2
n+6
sync
pause
n+5
(skipped)
CRC
CRC
data
stat
sync
CRC
data
stat
sync
pause
n+4
data
(skipped)
n+3
(skipped)
stat
n+2
(skipped)
sync
n+1
pause
n
internal
update
SENT message 3
Figure 17: Pause Pulse Used to Extend the Message to Match the Frame Rate (SENT_UPDATE = 1)
A constant message frame rate is used, and for each message, a Pause pulse is used to extend the message to match the frame rate (SENT_
UPDATE = 1). Internal updates may be skipped or repeated depending on the BW bandwidth and SENT_TICK time settings. The quantity of
skipped or repeated internal updates can vary from message to message.
Note: Although the frame transmission rate is constant, discrete SENT messages do not represent equal time interval sampling of the magnetic field.
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High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
SENT
message
Panel 18(c): The internal update rate is the same as in panel (b), but
the tick duration is reduced slightly. The longest possible SENT message is now synchronized at the internal update rate. Each update is
ready before the synchronization nibble is composed, and is transmitted. No updates are skipped.
SENT
message
SENT message 1
data
stat
sync
data
stat
n+2
CRC
pause
data
n+1
(skipped)
sync
n
sync
data
SENT message 1
pause
CRC
data
Panel 18(b): The filter bandwidth is reduced by twice relative to the
bandwidth in panel (a), which doubles the internal update interval.
The longest possible SENT message is now synchronized at two
times the internal update rate. The first update is ready before the
synchronization nibble is composed, and is transmitted. Two more
updates occur before the next SENT message, so only the second
update data is included, and the one intervening update is skipped.
internal
update
stat
sync
CRC
pause
data
stat
sync
n+1
n+2
SENT message 1
stat
Panel 18(a): The longest possible SENT message is synchronized at
three times the internal update rate. The first update is ready before
the synchronization nibble is composed, and is transmitted. Three
more updates occur before the next SENT message, so only the
third update data is included, and the two intervening updates are
skipped.
n
n+1
(skipped)
SENT
message
SENT message 1
internal
update
n
stat
data
sync
internal
update
stat
CRC
stat
SENT
message
pause
n+1
n+2
n+3
(skipped)
(skipped)
data
n
sync
internal
update
sync
A1341
SENT
Panel 18(d): The faster update rate of panel (a) and the shorter tick
duration of panel (c) are applied. Because the panel (d) higher bandwidth setting also applies, the overall A1341 response time is faster
than that shown in panel (c). However, the panel (c) settings reduce
front-end noise better than those of panel (d), because of the lower
bandwidth.
Figure 18: SENT Message Rate Synchronized with the Internal A1341 Internal Update Rate.
For each message, a Pause pulse is used to extend the message to match the internal update rate (SENT_UPDATE = 2). A consistent number
of updates are skipped or repeated from message to message. The internal update value transmitted is from the last update ready before the
Synchronization and Calibration nibble of the message is composed.
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A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
The SENT_UPDATE parameter has two other options, which
allow direct control of when magnetic field data is sent to the
external controller:
• Tandem data latching and sending (SENT_UPDATE = 3)
• Immediate data latching with a controllable delay before
sending (SENT_UPDATE = 4)
When SENT_UPDATE = 3 (upper panel in Figure 19), while
the A1341 has a Pause pulse on the device output, the controller
triggers a latch-and-send sequence by pulling the A1341 output
low. When the controller releases the output, the current magnetic
field data is latched, and after a delay of tdSENT the latched data
is sent to the controller. This option is useful when the controller
Controller pulls OUT low
requires a prompt response on the current magnetic field.
When SENT_UPDATE = 4 (lower panel in Figure 19), while
the A1341 has a Pause pulse on the device output, the controller triggers a latch-and-send sequence by pulling the output
low. With this option, the current magnetic field data is latched
immediately. This allows the controller to postpone receiving the
data. When the output is eventually released, the data is sent to
the controller after a delay of tdSENT . This option is useful where
multiple A1341s are connected to the controller (see Typical
Application, Figure 8). All the A1341s can be instructed at the
same time to latch magnetic field data, and the controller can then
retrieve the data from each A1341 individually.
Controller releases OUT; magnetic data latched
SENT
messages
sync
pause
CRC
data
stat
...
Waiting
period, twait
sync
VOUTx
pause
tdSENT (6 ticks)
Sensor IC starts message containing latched data
...
...
(previous message)
SENT message
Controller pulls OUT low;
magnetic data latched
Controller releases OUT
tdSENT (6 ticks)
SENT
messages
(previous message)
sync
pause
CRC
data
stat
Waiting
...
period, twait
sync
VOUTx
pause
Sensor IC starts message containing latched data
...
...
SENT message
Figure 19: Device Output Behavior where Normal Operation Magnetic Field Data is Latched at a Defined Time:
(upper panel) if SENT_UPDATE = 3, latched and sent at end of a low pulse, or (lower panel) if SENT_UPDATE = 4, latched at the beginning of a
low pulse, but not sent until the end of the pulse. The total delay from the beginning of the low pulse until the data message begins is: twait +
tdSENT .
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High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
The general format of a command message frame is shown
in Figure 15. The individual sections of a SENT message are
described in Table 13.
Table 13: SENT Message Frame Section Definitions
Section
Description
Synchronization and Calibration
Function
Syntax
Provide the external controller with a detectable start of the message frame. The large quantity of ticks distinguishes this section,
for ease of distinction by the external controller.
Nibbles: 1
Quantity of ticks: 56
Quantity of bits: 1
Status and Communication
Function
Syntax
Provides the external controller with the status of the A1341 and indicates the format and contents of the Data section.
Nibbles: 1
Quantity of ticks: 12 to 27
Quantity of bits: 4
1:0 Device status (set by SENT_STATUS parameter)
3:2 Message serial data protocol (set by SENT_SERIAL parameter)
Data
Function
Syntax
Provides the external controller with data selected by the SENT_DATA parameter.
Nibbles: 3 to 6
Quantity of ticks: 12 to 27 (each nibble)
Quantity of bits: 4 (each nibble)
CRC
Function
Syntax
Provides the external controller with cyclic redundancy check (CRC) data for certain error detection routines applied to the Data
nibbles and to the Status information.
Nibbles: 1
Quantity of ticks: 12 to 27 (each nibble)
Quantity of bits: 4
Pause Pulse
Function
Syntax
(Optional) Additional time can be added at the end of a SENT message frame to ensure all message frames are of appropriate
length. The SENT_UPDATE parameter sets format.
Nibbles: 1
Quantity of ticks: 12 minimum (length determined by SENT_UPDATE option and by the individual structure of each SENT
message)
Quantity of bits: n.a.
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33
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
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 Correction) check bits, stored as shown in Figure 20.
EEPROM Bit
Contents
29
28
27
26
25
24
23
22
21
20
19
18
17
D23 D22 D21 D20 D19 D18 D17 D16 D15 D14 D13 D12 D11
16
15
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 20: EEPROM Word Bit Sequence; C# – Check Bit, D# – Data Bit
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
34
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
Table 14: EEPROM Register Map of Customer-Programmable Parameters
Address
Bits
Parameter Name
0x07
23:21
Reserved
0x07
20:18
OUTDRV_CFG
0x07
17:0
SENTPWM_CFG
Description
Output Driver Setting
SENT and PWM output mode configuration parameters
(assignment determined by PWM_MODE bit)
17:11
SENT_TICK
Sets Tick Rate Coefficient (PWM_MODE = 0)
10:9
SENT_FIXED
Sets Fixed State interval (PWM_MODE = 0)
Sets Fixed State Assignment (PWM_MODE = 0)
8
SENT_LOVAR
7:5
SENT_UPDATE
4:3
SENT_DATA
DAC profile
Sets Pause Pulse and Message Frame Rate (PWM_MODE = 0)
Sets Data Nibble Format (PWM_MODE = 0)
2
SENT_STATUS
Sets Error Condition (PWM_MODE = 0)
1:0
SENT_SERIAL
Sets Message Series Format (PWM_MODE = 0)
3
CALIBRATE_PWM
2:0
FPWM
Enables 50% Duty Cycle Calibration (PWM_MODE = 1)
0x08
23:15
TC2_SENS_HOT
2nd Order Sensitivity Temperature Coefficient, ΔT (from 25°C) > 0
Two’s complement
0x08
14:6
TC2_SENS_CLD
2nd Order Sensitivity Temperature Coefficient, ΔT (from 25°C) < 0
Two’s complement
0x08
5:2
SENS_COARSE
Factory Trimmed Magnetic Input Signal Range
Non-uniform
Non-uniform
Sets PWM Carrier Frequency (PWM_MODE = 1)
0x08
1:0
Reserved
Reserved for system use (bits written here will not affect device
operation)
0x09
23:16
TC1_SENS_HOT
1st Order Sensitivity Temperature Coefficient, ΔT (from 25°C) > 0
Non-uniform
0x09
15:8
TC1_SENS_CLD
1st Order Sensitivity Temperature Coefficient, ΔT (from 25°C) < 0
Non-uniform
0x09
7:0
TC1_OFFSET
1st
0x0A
23:12
SCRATCH_C
Customer Scratchpad
0x0A
11:0
SENS_MULT
Output Sensitivity/ Sensitivity Multiplier
0x0B to 0x1A
23:12
LINPOS_COEFF
(LIN_1, LIN_3, ..., LIN_31)
Linearization Coefficients (odd-numbered sampling positions)
Two’s complement
0x0B to 0x1B
11:0
LINPOS_COEFF
(LIN_0, LIN_2, ..., LIN_32)
Linearization Coefficients (even-numbered sampling positions)
Two’s complement
Order Magnetic Offset TC Compensation
0x1B
23
LIN_TABLE_DONE
Linearization Coefficients Loaded Flag
0x1B
22
LIN_OUTPUT_INVERT
Linearization Output Polarity Inversion
0x1B
21
LIN_INPUT_INVERT
0x1B
20:12
ID
0x1C
23:18
CLAMP_HIGH
Clamp Upper Limit
0x1C
17:12
CLAMP_LOW
Clamp Lower Limit
0x1C
11
EEPROM_LOCK1
0x1C
10
OVLO_LO
Overvoltage Lockout Threshold
Low Voltage Detection Disable
Two’s complement
Linearization Input Polarity Inversion
Customer Identification Number
Customer EEPROM Lock
0x1C
9
LVD_DIS
0x1C
8:4
SIG_OFFSET
Factory Trimmed Magnetic Offset Compensation (Coarse)
0x1C
3
PWM_MODE
Normal Operation Output Mode (SENT / PWM)
0x1C
2:0
BW
0x1D
23:12
SCRATCH_C
Customer Scratchpad
0x1D
11:0
QOUT_FINE
Fine Quiescent Output Duty Cycle
Two’s complement
Bandwidth
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
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
35
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
EEPROM Customer-Programmable Parameter Reference
Table 15: BW (Register Address: 0x1C, bits 2:0)
Function
Filter Bandwidth
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.
This selection also sets the internal update rate.
Syntax
Quantity of bits: 3
Related Commands
–
Code
000 (Default)
001
010 (Same)
011
100
101
110
111
Values
Options
–
Examples
–
A-to-D Converter Output Rate
(Typical)
(kHz)
Filter 3 dB Bandwidth
(Typical)
(Hz)
8.
16
8
4
2
1
Factory Use Only
Factory Use Only
1500
3000
1500
750
375
188
–
–
Table 16: CALIBRATE_PWM (Register Address: 0x07, bit 3)
Function
PWM Calibration
Sent at power-on, commands the device to calculate the PWM 50% duty cycle to the centerpoint of the Full Scale
Output range.
Syntax
Quantity of bits: 1
Related Commands
PWM_MODE (see EEPROM Structure Section)
Values
Options
None
Examples
–
0: Disable calibration (Default)
1: Enable calibration
Table 17: CLAMP_HIGH (Register Address: 0x1C, bits 23:18)
Function
Clamp Upper Limit
Sets the percentage of the upper half of the Full Scale Output signal passed through at the end of the Digital Signal
Processing stage.
Syntax
Quantity of bits: 6
Related Commands
CLAMP_LOW
Values
000000: 100%FSO (PWM: 95% maximum duty cycle, SENT: 4095) (Default)
111111: 50.78%FSO (PWM: 50% duty cycle, SENT: 2047)
Options
The factory-programmed default, OUTCLP(H)init , is used if this parameter is not set.
Examples
–
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
36
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
Table 18: CLAMP_LOW (Register Address: 0x1C, bits 17:12)
Function
Clamp Lower Limit
Sets the percentage of the lower half of the Full Scale Output signal passed through at the end of the Digital Signal
Processing stage.
Syntax
Quantity of bits: 6
Related Commands
CLAMP_HIGH
Values
Options
The factory-programmed default, OUTCLP(L)init , is used if this parameter is not set.
Examples
–
000000: 0% FSO (PWM: 5% duty cycle, SENT: 0) (Default)
111111: 49.22% FSO (PWM: 50% duty cycle, SENT: 2047)
Table 19: EEPROM LOCK: Address 0x1C, bit 11
Function
Disables writing into the device memory
Syntax
Quantity of bits: 1
Related Commands
–
Values
Options
Lock bit feature is enabled following a reset of the device power after setting the EEPROM LOCK bit.
Examples
Refer to Memory Locking Mechanisms section for more information.
0 (default) Default memory lock mechanism
1 Prevents any Read or Write transaction with the device
Table 20: Customer_ID (Register Address: 0x1B, bits 20:12)
Function
Customer Identification Number
Available register for identifying the A1341 for multiple-unit applications.
Syntax
Quantity of bits: 12
Related Commands
SCRATCH_C
Values
Free-form
Options
–
Examples
–
EEPROM Lock
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
37
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
Table 21: FPWM (Register Address: 0x07, bits 2:0)
Function
PWM Carrier Frequency
Sets the carrier frequency for PWM mode normal output (voltage response to applied magnetic field). Selected
frequency determines maximum output resolution.
Syntax
Quantity of bits: 3
Related Commands
PWM_MODE (see EEPROM Structure Section)
Code
000 (Default)
001
010
011
100
101
110
111
Values
Options
–
Examples
–
PWM Frequency (Typical)
(kHz)
Maximum Output Resolution
(bits)
0.125
0.25
0.5
1
2
4
0.125
0.125
12
12
12
11
10
9
12
12
Table 22: LIN_INPUT_INVERT (Register Address: 0x1B, bit 21)
Function
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.
Syntax
Quantity of bits: 1
Related Commands
LIN_x, LIN_OUTPUT_INVERT
Values
0: No inversion of signal before input into the linearization block. (Default)
1: Input signal inverted before it is sent into the linearization block.
Options
–
Examples
–
Table 23: LIN_OUTPUT_INVERT (Register Address: 0x1B, bit 22)
Function
Inverts the polarity of the input signal after the linearization block. (Can be used to invert the output polarity without
populating the linearization table.)
Syntax
Quantity of bits: 1
Related Commands
LINPOS_COEFF, LIN_INPUT_INVERT
Values
0: No inversion of signal after processing in the linearization block. (Default)
1: Input signal inverted after processing in the linearization block.
Options
–
Examples
–
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
38
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
Table 24: 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)
Function
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.
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
LIN_INPUT_INVERT, LIN_OUTPUT_INVERT, LIN_TABLE_DONE
Values
Calculated according to applied magnetic field
Output
Position
(%FSI)
EEPROM
Address
Bits
BIN0
100
0x0B
11:00
Input
Sample
Options
Examples
Output
Position
(%FSI)
EEPROM
Address
Bits
BIN16
16/32
0x13
11:00
Input
Sample
BIN1
31/32
0x0B
23:12
BIN17
15/32
0x13
23:12
BIN2
30/32
0x0C
11:00
BIN18
14/32
0x14
11:00
23:12
BIN3
29/32
0x0C
23:12
BIN19
13/32
0x14
BIN4
28/32
0x0D
11:00
BIN20
12/32
0x15
11:00
BIN5
27/32
0x0D
23:12
BIN21
11/32
0x15
23:12
BIN6
26/32
0x0E
11:00
BIN22
10/32
0x16
11:00
BIN7
25/32
0x0E
23:12
BIN23
9/32
0x16
23:12
BIN8
24/32
0x0F
11:00
BIN24
8/32
0x17
11:00
BIN9
23/32
0x0F
23:12
BIN25
7/32
0x17
23:12
BIN10
22/32
0x10
11:00
BIN26
6/32
0x18
11:00
BIN11
21/32
0x10
23:12
BIN27
5/32
0x18
23:12
BIN12
20/32
0x11
11:00
BIN28
4/32
0x19
11:00
BIN13
19/32
0x11
23:12
BIN29
3/32
0x19
23:12
BIN14
18/32
0x12
11:00
BIN30
2/32
0x1A
11:00
BIN15
17/32
0x12
23:12
BIN31
1/32
0x1A
23:12
BIN32
0
0x1B
11:00
–
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
39
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
Table 25: LIN_TABLE_DONE (Register Address: 0x1B, bit 23)
Function
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.
Syntax
Quantity of bits: 1
Related Commands
LINPOS_COEFF
Values
Options
–
Examples
–
0: Linearization algorithm applies default coefficients to the processed signal (Default)
1: Linearization algorithm applies customer-loaded coefficients to the processed signal
Table 26: LVD_DIS: Address 0x1C bit 9
Function
Low Voltage Detection Disable
Disable the low voltage detection feature.
Syntax
Quantity of bits: 1
Related Commands
–
Values
0: Default, Low Voltage Detection enabled.
1: Low Voltage Detection disabled.
Options
–
Examples
–
Table 27: OUTDRV_CFG (Register Address: 0x07, bits 20:18)
Function
Output Signal Configuration
Sets configuration of the output signal slew-rate control. Sets the ramp rate on the gate of the output driver, thereby
changing slew rate at the output.
Syntax
Quantity of bits: 3
Related Commands
–
Fall Time (Typical)
(µs)
Code
000 (Default)
001
010
011
100
101
110
111
Values
Options
–
Examples
–
CLOAD = 100 pF
CLOAD = 1 nF
CLOAD = 10 nF
0.048
0.114.
0.202
0.290
0.760
1.539
3.161
4.819
0.149
0.217
0.309
0.400
0.854
1.555
2.978
4.442
1.324
1.323
1.404
1.492
1.948
2.669
4.118
5.557
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
40
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
Table 28: OVLO_LO (Register Address: 0x1C, bit 10)
Function
Overvoltage Lockout Threshold
Sets the typical threshold value.
Syntax
Quantity of bits: 1
Related Commands
–
Values
Options
–
Examples
–
0: 19.3 V typical (Default)
1: 6.5 V typical
Table 29: PWM_MODE (Register Address: 0x1C, bit 3)
Function
Normal Operation Output Mode
Changes normal output (voltage response to applied magnetic field) from SENT to PWM.
Syntax
Quantity of bits: 1
Related Commands
CALIBRATE_PWM, FPWM
Values
Options
–
Examples
–
0: SENT (Default)
1: PWM
Table 30: QOUT_FINE (Register Address: 0x1D, bits 11:0)
Function
Quiescent Output (QOUT)
Adjusts the device normal output (digital response to applied magnetic field) to set the baseline output level: for a
quiescent applied magnetic field (BIN ≈ 0 G).
Syntax
Quantity of bits: 12
Code stored in two’s complement format
Related Commands
SIG_OFFSET
Values
0111 1111 1111: +49.98% of output full scale range (Default)
1000 0000 0000: –50% of output full scale range
Options
The factory-programmed default, QOUT , is used if this parameter is not set.
Examples
–
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
41
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
Table 31: SCRATCH_C (Register Address: 0x1D, bits 23:12)
Function
Customer Scratchpad
For optional customer use in storing values in the device.
Syntax
Quantity of bits: 12
Two independent locations
Related Commands
IC
Values
Free-form field
Options
–
Examples
–
Table 32: SENS_COARSE (Register Address: 0x08, bits 5:2)
Offset drifts with temperature changes will be altered from the factory programmed values after the Coarse Sensitivity is changed. If a change
in Coarse Sensitivity is unavoidable, please contact Allegro for detailed information.
Function
Coarse Sensitivity
Sets the nominal (coarse) sensitivity of the device, SENS_COARSE, which can be defined as OUT / 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.)
Syntax
Quantity of bits: 4
Related Commands
SIG_OFFSET, SENS_MULT
Code
Values
Coarse Sensitivity at VCC = 5 V
(Typical)
(%FSO/G)
RANGE
(Typical)
(G)
0000 (Default)
0001
0010
0011
0100
0101
0110
0111
0.100
0.333
0.250
0.200
0.167
0.125
0.080
0.067
±500
±150
±200
±250
±300
±400
±625
±750
1000
1001
1010
1011
1100
1101
1110
1111
0.057
0.050
0.040
0.033
0.029
0.025
0.5
0.022
±875
±1000
±1250
±1500
±1750
±2000
±100
±2250
Options
The default, SENS = 0.1%FSO/G for SENS_COARSE and BIN = ±500 G for RANGE are used if this parameter is
not set.
Output accuracy is reduced with codes 1110 and 1111.
Examples
To set a sampled BIN range of 500 G, set RANGE = ±250 G (SENS_COARSE = 0011). That would also set Coarse
Sensitivity to 0.2%FSO/G (SENS_COARSE = 0011).
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
42
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
Table 33: SENS_MULT (Register Address: 0x0A, bits 11:0)
Function
Sensitivity Multiplier
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
The SENS_MULT values are mapped to the programming code values as follows:
2.0
Syntax
SENS_MULT 1.0
Value
0
0
0x800
0xFFF
SENS_MULT Code
Related Commands
RANGE (SENS_COARSE), TC1_SENS_CLD, TC1_SENS_HOT, TC2_SENS_CLD, TC2_SENS_HOT
Values
–
Options
SENS_OUT = SENS_COARSE, that is, SENS_MULT = 1 (code 0) if this parameter is not set.
Examples
At: RANGE = ±500 G,
SENS_COARSE code and available range:
0000: 0.1%FS/G nominal
SENS_MULT maximum code gives 0.2%FSO/G nominal
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
43
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
Table 34: SENT_DATA (Register Address: 0x07, bits 4:3)
Function
Data Nibble Format
Quantity and contents of Data nibbles in message. (Does not relate to data contained in the Status and
Communication nibble.)
Syntax
Quantity of Bits: 2
Related Commands
–
Values
0 0: Nibbles 1,2,3: magnetic field data; nibbles 4,5: counter data;
nibble 6: inverted nibble 1 (Default)
0 1: Nibbles 1,2,3: magnetic field data; nibbles 4,5: counter data;
nibble 6: all zeros
1 0: Nibbles 1,2,3: magnetic field data; nibbles 4,5,6: current temperature data
1 1: Nibbles 1,2,3: magnetic field data (nibbles 4,5,6 skipped)
Options
–
Examples
–
Table 35: SENT_FIXED (Register Address: 0x07, bits 10:9)
Function
Fixed Interval Duration
Indicates the quantity of ticks in fixed-duration intervals.
Syntax
Quantity of Bits: 2
Related Commands
SENT_LOVAR
Values
0 0:
0 1:
1 0:
1 1:
5 ticks (Default)
4 ticks
7 ticks
8 ticks
Options
SENT_FIXED = 1 ( 4 ticks) does not meet the SENT spec, but is provided for custom fast or improved-EMI
communication.
Examples
–
Table 36: SENT_LOVAR (Register Address: 0x07, bit 8)
Function
State Assignments
Assigns fixed duration state (becomes delimiting state; other interval becomes the information state)
Syntax
Quantity of Bits: 1
Related Commands
SENT_FIXED
Values
0: Low interval of every nibble is fixed in duration, and the high interval becomes the information state (Default)
1: High interval of every nibble is fixed in duration, and the low interval becomes the information state
Options
SENT_LOVAR = 0 meets the SENT specification.
SENT_LOVAR = 1 does not meet the SENT spec, but is provided for custom improved-EMI communication.
For SENT_UPDATE = 3 or 4, the Pause pulse has a fixed low time regardless of
the SENT_LOVAR setting.
Examples
–
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
44
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
Table 37: SENT_SERIAL (Register Address: 0x07, bits 1:0)
Function
Status and Communication Nibble Format
Defines values of bits 2 and 3 inside the Status and Communication nibble.
Syntax
Quantity of Bits: 2
Related Commands
–
0 0: Bits 2 and 3 are 0 (Default)
0 1: Bits 2 and 3 are 0 part of the Short Serial protocol: 8-bit value data, 4-bit message ID,
16 SENT frames are required to send an entire serial message
1 0: Bits 2 and 3 are part of the Enhanced 16-bit Serial protocol: 12-bit value data, 4-bit
message ID, 18 SENT frames are required to send an entire serial message
1 1: Bits 2 and 3 are part of the Enhanced 24-bit Serial protocol: 16-bit value data, 8-bit
message ID, 18 SENT frames are required to send an entire serial message
Values
Options
–
Examples
–
Table 38: SENT_STATUS (Register Address: 0x07, bit 2)
Function
Error Condition Status
Defines values of bits 0 and 1 inside the Status and Communication nibble.
Defines data inside the Status and Communication nibble on device error status.
Syntax
Quantity of Bits: 1
Related Commands
SENT_SERIAL
Values
(SENT_STATUS = 0)
0 0: No error (Default)
0 1: Not used
1 0: Overvoltage condition
1 1: Nonrecoverable EEPROM error, bad Linearization table or other error
(SENT_STATUS = 1)
0 0: No error (Default)
0 1: Error condition
Options
–
Examples
A Status and Communication nibble value of 0010 indicates an overvoltage condition.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
45
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
Table 39: SENT_TICK (Register Address: 0x07, bits 17:11)
Function
Tick Duration
Sets the SENT tick rate coefficient: 4 MHz / SENT_TICK = tick (µs)
Syntax
Quantity of Bits: 7
Any value from 0 to 127 can be used
Related Commands
–
Values
Code
PWM Frequency (Typical)
(µs)
Coefficient
(MHz/SENT_TICK)
000 0000
000 0001
000 0010
000 0111
111 1111
111 1110
111 1111
3.0 (Default)
0.25
0.5
0.75
32
31.5
31.75
4/12
4/1
4/2
4/3
4/125
4/126
4/127
Options
SENT_TICK = 1 through 11 do not meet the SENT spec, but are provided for custom fast communication.
Examples
–
Table 40: SENT_UPDATE (Register Address: 0x07, bits 7:5)
Function
Pause Pulse and Frame Rate
Pause pulse usage and message frame rate.
Syntax
Quantity of Bits: 3
Related Commands
SENT_LOVAR
Values
000: No Pause pulse; new frame immediately follows previous frame (Default)
001: Pause pulse used for minimum constant frame rate (Length of other message
sections, plus length of Pause Pulse nibble, is constant. For the maximum message
length, Pause pulse information state is the minimum size of 12 ticks.)
010: Pause pulse used for constant frame rate, synchronized with A1341 internal update
rate. (Handshaking occurs such that the Synchronization and Calibration nibble starts
immediately after the next new data word is ready.)
011: Pause pulse held indefinitely until receipt of trigger pulse (OUT pulled low) from the
controller, data latched after output released and message is sent.
100: Pause pulse held indefinitely until receipt of trigger pulse (OUT pulled low) from the
controller, data latched immediately and sent when output is released.
101, 110, 111: Same function as 000.
Options
–
Examples
–
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115 Northeast Cutoff
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46
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
Table 41: SIG_OFFSET (Register Address: 0x1C, bits 8:4)
If changing Coarse Magnetic Offset cannot be avoided because of application requirements, please contact Allegro for detailed information.
Function
Magnetic Offset Compensation (Coarse)
Adjusts the center of the selected BIN range (SIG_OFFSET) to adapt to the application magnetic field.
Syntax
Quantity of bits: 5
Code stored in two’s complement format.
Related Commands
RANGE, TC1_OFFSET
Code
Values
SIG_OFFSET
(% of Full-Scale RANGE)
00000 (Default)
00001
00010
00011
00100
00101
00110
00111
0.00
6.25
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
10000
10001
10010
10011
10100
10101
10110
10111
–100.00
–93.75
–87.50
–81.25
–75.00
–68.75
–62.50
–56.25
11000
11001
11010
11011
11100
11101
11110
11111
–50.00
–43.75
–37.50
–31.25
–25.00
–18.75
–12.50
–6.25
Options
The default, QOUT , is used if this parameter is not set.
Examples
To set the input range from 0 to 1000 G, with a centerpoint at +500 G:
1. Leave SENS_COARSE at 0.1%FSO/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%
3. Set the SIG_OFFSET code to 11000 (24), to select SIG_OFFSET = –50%.
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115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
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47
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
Table 42: TC1_OFFSET (Register Address: 0x09, bits 7:0)
Function
1st Order Magnetic Offset Temperature Compensation coefficient
Syntax
Quantity of bits: 8
Code stored in two’s complement format.
Related Commands
SIG_OFFSET, TC1_SENS_CLD, TC1_SENS_HOT, TC2_SENS_CLD, TC2_SENS_HOT
Values
0000 0000: Default
0111 1111: +0.48 G/°C
1000 0000: –0.48 G/°C
Options
No fine magnetic offset is applied if this parameter is not set.
Examples
–
Table 43: TC1_SENS_CLD (Register Address: 0x09, bits 15:8)
TC1_SENS_HOT (Register Address: 0x09, bits 23:16)
Function
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
• 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
Values
0000 0000: –98 m% / °C
1111 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.
Examples
Refer to Temperature Compensation section.
Table 44: TC2_SENS_CLD (Register Address: 0x08, bits 14:6)
TC2_SENS_HOT (Register Address: 0x08, bits 23:15)
Function
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
• 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
Values
0 0000 0000: –1.53 m% / °C
1 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.
Examples
Refer to Temperature Compensation section.
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115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
48
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
DEFINITION OF TERMS
Full Scale (FSI and FSO)
Quiescent Output (QOUT)
Full Scale Input, FSI, is the range of the applied magnetic field
processed by the device. Full Scale Output, FSO, is the range of
output values that device output can have for the applied magnetic field. If device output is configured as PWM, output will
be 5% and 95%. If device output is configured as SENT, device
output will obtain LSB values from 0 to 4095. See Figure 21.
The output value in the quiescent state (when no magnetic field is
applied, BIN = 0 G).
Power-On Time (tPO)
The time required for device output to generate either the first
valid output message frame (SENT mode) or the first valid duty
cycle (PWM mode), after the power supply has reached its minimum 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.
Signal Propagation Delay (tPROP)
The time necessary for the device to respond to an input magnetic
change and to create a valid output message.
Signal Response Time (tRESP)
Typically Signal Response Time is defined as propagation
delay plus length of the SENT/PWM message. However if filter
bandwidth is chosen such that the corresponding internal output
update rate (see BW parameter in EEPROM) is slower than the
output digital message length, it might take a couple of output
messages to update the user.
Output Mode
PWM
SENT
(D %)
(LSB)
100
FSO
FSI
(RANGE) (%)
100
0
50
0
95
1111 1111 1111 1111
50.78
49.22
1000 0000 0000 0000
5
0000 0000 0000 0000
(4095)
(2048)
(0)
B–
0
B+
Applied Magnetic
Field, BIN (G)
Figure 21: Full Scale Input (FSI) and Full Scale Output
(FSO)
The central portion of the programmable range for Quiescent
Output, QOUT, range lies within the QOUT limits. The
Quiescent Output, QOUT , can be customer-programmed around
its typical value , which is 0 LSB (SENT mode) or 50% duty
cycle (PWM mode).
Quiescent Output Drift Through Temperature
Range
Due to internal component tolerances and thermal considerations,
the temperature coefficient used to determine Quiescent Output
may drift from its typical initial value, OUT(Q) , when changes
occur in the operating ambient temperature, TA. For purposes of
specification, the Quiescent Output Drift Through Temperature
Range, ΔOUT(Q) , is defined as:
ΔOUT(Q) = OUT(Q)TA − OUT(Q)25°C
(5)
where OUT(Q)TA is the OUT(Q) at a given TA and OUT(Q)25°C is
the OUT(Q) at a TA of 25°C. Note that ΔOUT(Q) should be calculated using actual measured values, rather than target values used
when programming.
The Offset Temperature Coefficient can be seen as representation
of the offset drift over temperature in units %/C:
∆OUT(Q) =
(OUT(Q)TA – OUT(Q)25°C ) / OUT(Q)25°C
∆TA
× 100
(6)
where ΔTA = TA – 25°C.
Sensitivity (Sens)
The proportion of the output voltage to the magnitude of the
applied magnetic field. This proportionality is specified as the
Sensitivity, Sens (ΔLSB/G for SENT mode, ΔD/G for PWM
mode), and is effectively the gain of the device.
An individual A1341 device may be unipolar, and respond to the
presence of either a south (positive) polarity magnetic field, or a
north (negative) polarity magnetic field (but not both). Or it may
be bipolar, and respond to both polarities. If responsive to a south
field, a south field opposite and perpendicular to the branded face
of the package will increase the output from its quiescent value
toward the maximum output limit. If responsive to a north field, a
north field opposite and perpendicular to the branded face of the
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49
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
package will decrease the output from its quiescent value.
purposes of specification, the Sensitivity Drift Due to Package
Hysteresis, is defined as:
For bipolar configurations, Sensitivity is defined as:
Sens =
OUT(BPOS) – OUT(BNEG)
BPOS – BNEG
,
(7)
and for unipolar configurations (south field responsive) as:
Sens =
OUT(BPOS) – OUT(Q)
BPOS
,
(8)
where BPOS and BNEG are two magnetic fields with the indicated
opposite polarities.
Sensitivity Drift Through Temperature Range
Due to internal component tolerances and thermal considerations,
the temperature coefficient used to determine Sensitivity may
drift from its typical initial value, SensTCinit , and the expected
value after customer programming (EEPROM parameters TC1_
SENS_CLD, TC1_SENS_HOT, TC2_SENS_CLD, TC2_SENS_
HOT) when changes occur in the operating ambient temperature,
TA. For purposes of specification, the Sensitivity Drift Through
Temperature Range, ∆SensTC , is defined as:
∆SensTC =
SensTA – SensEXPECTED(TA)
SensEXPECTED(TA)
× 100 (%) . (9)
where SensTA is the actual Sens at the current ambient temperature, and SensEXPECTED(TA) is the Sens calculated based on
programmed parameters.
Sensitivity Temperature Coefficient can be seen as a representation of the Sensitivity drift in %/°C when a temperature divider,
∆T = TA – 25°C, is inserted into equation 9.
Sensitivity Drift Due to Package Hysteresis
(∆SensPKG)
Package stress and relaxation can cause the device sensitivity at
TA = 25°C to change during and after temperature cycling. For
∆SensPKG =
Sens(25°C)2 – Sens(25°C)1
Sens(25°C)1
× 100 (%)
(10)
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.
Linearity Sensitivity Error
The A1341 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.
Linearity Error is calculated separately for the positive
(LinERRPOS ) and negative (LinERRNEG ) applied magnetic
fields. Linearity error is measured and defined as:
SensBx 

SensBx/2 
× 100 (%)
Sens–Bx


LinERRNEG = 1–
Sens
–Bx/2

where:
× 100 (%)

LinERRPOS = 1–

SensBx =
|OUT(Bx) – OUT(Q)|
Bx
(11)
(12)
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).
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115 Northeast Cutoff
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1.508.853.5000; www.allegromicro.com
50
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
A1341
PACKAGE OUTLINE 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°
5.21
+0.08
–0.05
1.00
+0.08
–0.05
E
2.60 F
1.00 F
Mold Ejector
Pin Indent
+0.08
3.43
–0.05
F
0.89 MAX
1
2
3
Branded
Face
4
A
0.54 REF
NNNN
YYWW
0.41
+0.08
0.20
–0.05
+0.08
–0.05
D
12.14 ±0.05
1.27 NOM
N = Device part number
Y = Last two digits of year of manufacture
W = Week of manufacture
0.54 REF
0.89 MAX
1.50
+0.08
–0.05
D
+0.08
5.21
–0.05
Standard Branding Reference View
A
Dambar removal protrusion (16X)
B
Gate and tie burr area
C
Branding scale and appearance at supplier discretion
D
Thermoplastic Molded Lead Bar for alignment during shipment
E
Active Area Depth, 0.37 mm REF
F
Hall element, not to scale
+0.08
1.00
–0.05
Package KT, 4-Pin SIP
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115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
51
A1341
High Precision, Programmable Linear Hall Effect Sensor IC
With EEPROM, SENT and PWM Output Protocols, and Advanced Output Linearization
Revision History
Revision
Revision Date
–
November 13, 2014
Description of Revision
Initial Release
Copyright ©2012-2014, 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
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115 Northeast Cutoff
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52
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