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A1340LKTTN-4-T [ALLEGRO]

High Precision Programmable Linear Hall Effect Sensor IC with EEPROM, Analog Output, and Advanced Output Linearization;
A1340LKTTN-4-T
型号： A1340LKTTN-4-T
厂家： ALLEGRO MICROSYSTEMS    ALLEGRO MICROSYSTEMS
描述：

High Precision Programmable Linear Hall Effect Sensor IC with EEPROM, Analog Output, and Advanced Output Linearization

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

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