MLX90251

MLX90251
Programmable Linear Hall Effect Sensor
Features and Benefits
Application Examples
Analog Signal Processing
Quad Switched Hall Plate
Chopper Stabilized Amplifier
Linear Analog Ratiometric Output Voltage
Programmable Output Quiescent Voltage (VOQ)
-100%VDD…200%VDD Range
Programmable Magnetic Sensitivity
Programmable Low Pass Filter
Programmable Clamping Voltage
Programmable Temperature Compensation
Melexis ID Number
Programmable Customer ID Number
Lead-free package
Linear Position Sensing
Rotary Position Sensing
Current Sensing
Magnetic Field Measurement
Ordering Code
Product Code
MLX90251
MLX90251
MLX90251
MLX90251
MLX90251
MLX90251
MLX90251
MLX90251
Temperature Code
E
E
E
E
L
L
L
L
Legend:
Temperature Code:
Package Code
VA
VA
VA
VA
VA
VA
VA
VA
Option Code
FAA-000
FAA-100
FAA-200
FAA-300
FAA-000
FAA-100
FAA-200
FAA-300
Packing Form Code
BU
BU
BU
BU
BU
BU
BU
BU
Package Code:
Option Code:
Packing Form:
L for Temperature Range -40°C to 150°C
E for Temperature Range -40°C to 85°C
VA for Plastic Single in Line thickness 1.1 -1.2mm
See section 10.4
BU for Bulk
Ordering example:
MLX90251LVA-FAA-000-BU
3901090251
Rev 012
Page 1 of 20
Data Sheet
Apr/12
MLX90251
Programmable Linear Hall Effect Sensor
2 General Description
1 Functional Diagram
Supply
1
Filter
OPA
OPA
OPA
4
3
DAC
DAC
DAC
DAC
DAC
DAC
2
Shift Register
E E P R O M
Figure 1-1 Functional Diagram
VDD
Test
VSS (Ground)
VOUT
Pin Out
VA package
1
2
3
4
Program
decoder
The MLX90251 is a CMOS Programmable,
Ratiometric Linear Hall Effect sensor IC. The
linear output voltage is proportional to the
magnetic flux density. The ratiometric output
voltage is proportional to the supply voltage. The
MLX90251 possesses active error correction
circuitry, which virtually eliminates the offset errors
normally associated with analog Hall Effect
devices. All the parameters of the MLX90251
transfer characteristic are fully programmable.
The VOQ (VOUT @ B = 0 Gauss), the Sensitivity,
the slope polarity, the Output Clamping levels, the
thermal Sensitivity drift, the internal bias point and
a low-pass filter are all programmable in end-user
applications. The MLX90251 has a very stable
thermal compensation for both the Sensitivity and
the VOQ over a broad temperature range. For
traceability purpose the MLX90251 will carry a
unique ID number programmed by Melexis and 24
bits of EEPROM memory are allocated for a user
programmed serial number.
Table 1: Pin out
3901090251
Rev 012
Page 2 of 20
Data Sheet
Apr/12
MLX90251
Programmable Linear Hall Effect Sensor
Table of Contents
1 Functional Diagram ........................................................................................................... 2
2 General Description .......................................................................................................... 2
3 Glossary of Terms ............................................................................................................. 4
4 Maximum Ratings ............................................................................................................. 4
5 Detailed Block Diagram ..................................................................................................... 5
5.1 Detailed Description .................................................................................................... 5
6 General Electrical Specifications ....................................................................................... 6
7 Programming Range ......................................................................................................... 7
8 Timing Specifications ........................................................................................................ 7
9 Accuracy ........................................................................................................................... 7
10 Programmable Features ................................................................................................. 8
10.1 Output Quiescent Voltage (VOQ)................................................................................ 9
10.2 Thermal VOQ Drift (DRIFT) ........................................................................................ 9
10.3 Sensitivity, Rough Gain and Fine Gain ..................................................................... 9
10.4 Sensitivity Range Selection ..................................................................................... 10
10.5 Sensitivity Polarity (INVERT)................................................................................... 12
10.6 Clamping Levels (CLAMPLOW, CLAMPHIGH)....................................................... 12
10.7 Filter (FILTER) ........................................................................................................ 13
10.8 Sensitivity Temperature Compensation (TC, TCW, TC2) ........................................ 13
10.9 Diagnostic Output Level (FAULTLEV) ..................................................................... 14
10.10 The EEPROM, Parity, and Melexis CRC .............................................................. 14
10.11 Output Amplifier Configuration (MODE) ................................................................ 14
10.12 Memory Lock (MEMLOCK) ................................................................................... 14
10.13 IC traceability ........................................................................................................ 15
11 Performance Graphs ..................................................................................................... 15
12 Applications Information ................................................................................................ 16
12.1 Application Circuits – VA-package .......................................................................... 16
12.2 Programming the Sensor ........................................................................................ 16
12.3 Calibration Procedure ............................................................................................. 17
13 Standard information regarding manufacturability of Melexis products with different
soldering processes ........................................................................................................... 18
14 ESD Precautions ........................................................................................................... 18
15 Package Information ..................................................................................................... 19
15.1 VA Package Outline and Hall Plate Position ........................................................... 19
16 Disclaimer ..................................................................................................................... 20
3901090251
Rev 012
Page 3 of 20
Data Sheet
Apr/12
MLX90251
Programmable Linear Hall Effect Sensor
3 Glossary of Terms
Term
mT (milli-Tesla)
VOQ (Output Quiescent
Voltage)
Sensitivity
TempCo (Sensitivity
Temperature Compensation)
PTC (Programming Through
the Connector)
MSB
LSB
Explanation
Unit of measurement for magnetic flux density. 1mT is equal to 10 Gauss.
Output voltage at zero magnetic field, VOUT for B = 0 mT.
Change in output voltage versus change in magnetic field (∆ VOUT / ∆ B)
Change in Sensitivity over temperature.
Listed in units of ppm / °C (where 100ppm / °C. = 0.01% / °C)
Melexis in-circuit programming protocol.
Most Significant Bit.
Least Significant Bit.
4 Maximum Ratings
Parameter
Maximum Supply Voltage, VDD_MAX (over
Voltage)
Units
30 V
Maximum Supply Current, IDD_MAX
(Over Voltage)
50 mA
Reverse Voltage, VDD_REV
- 15 V
Reverse Supply Current, IDD_REV
- 85 mA
Positive Output Voltage, VOUT_MAX
24 V
Positive Output Current, IOUT_POS_FAULT
40 mA
Reverse Output Voltage, VOUT_REV
- 0.7 V
Reverse Output Current, IOUT_REV_FAULT
-50 mA
Operating Ambient Temperature Range, TA
-40°C to 150°C
Storage Temperature Range, TS
Magnetic Flux Density
Table 2: Absolute Maximum Ratings
-55°C to 165°C
Infinite
Note: Exceeding the absolute maximum ratings may cause permanent damage. Exposure to absolutemaximum-rated conditions for extended periods may affect device reliability.
3901090251
Rev 012
Page 4 of 20
Data Sheet
Apr/12
MLX90251
Programmable Linear Hall Effect Sensor
5 Detailed Block Diagram
Figure 5-1 Detailed Block Diagram
5.1 Detailed Description
Integrated on the MLX90251 is a temperature-compensated quad switched Hall plate, chopper stabilized
amplifiers, adjustable output filter, output driver, voltage protection circuitry and a programmable EEPROM
with security and redundancy. Programming the EEPROM allows each device to be calibrated in the
application.
In normal operation data stored in the EEPROM feeds a register, RAM, that updates internal DACs and
switches that effect the operation of the device. In programming mode the RAM can be directly accessed to
allow faster calibration of the parameters. Communication to the device is done using Melexis' PTC serial
interface.
3901090251
Rev 012
Page 5 of 20
Data Sheet
Apr/12
MLX90251
Programmable Linear Hall Effect Sensor
6 General Electrical Specifications
DC operating parameters at VDD = 5V (unless otherwise specified) and for TA as specified by the temperature
range (E or L).
Parameter
Symbol
Test Conditions
Min
Typical Max
Units
Nominal Supply Voltage
VDDNOM
5
V
Operating Supply Voltage
VDD†
Nominal Supply Current
IDDNOM
Supply Current
4.5
-
5.5
V
VDD = VDDNOM
4.0
7.0
8.0
mA
IDD
VDD = 4.5 … 5.5 V
3.0
-
9.0
mA
VOUTPD
Pull Down Load ≥ 10 kΩ
no clamping
2
96
%VDD
VOUTPU
Pull Up Load ≥ 10 kΩ
no clamping
5
97
%VDD
Output Current
IOUT
VDD = VDDNOM
-1.25
1.25
mA
Output Short-Circuit Current
IOUTSC+
IOUTSC-
VDD = VDDNOM
Output shorted to supply-permanent
Output shorted to ground-permanent
-12
4
-4
12
mA
mA
0.5
%VDD
Output Voltage Swing
VOUT1
Broken supply,
Pull-down load > 10 kΩ
0
VOUT2
Broken ground,
Pull-down load > 10 kΩ
94
96
100
%VDD
VOUT3
Broken supply,
Pull-up load > 10 kΩ
0
3
5
%VDD
VOUT4
Broken ground,
Pull-up load > 10 kΩ
99.5
100
%VDD
Power on Reset
VDD_POR
Voltage on VDD
1.5
3.8
V
Over Voltage Detection
VDD_OVD
6.5
8.5
V
Diagnostic Output Voltage
Voltage on VDD
Table 3: Electrical Specifications
†
The ratiometric output voltage is proportional to the supply voltage. When using the supply voltage as a
reference for an A/D converter, fluctuations of ±10% in supply voltage are compensated.
3901090251
Rev 012
Page 6 of 20
Data Sheet
Apr/12
MLX90251
Programmable Linear Hall Effect Sensor
7 Programming Range
TA programming 20°C to 30°C.
Parameter
Symbol
Output Quiescent Voltage
VOQ
Sensitivity
S
Output Clamping Voltage Low
ClampLo
Output Clamping Voltage High
ClampHi
Temperature Compensation
Test Conditions
AGND = Default
AGND = 0…1023
Min
-10
-100
Typical Max
110
200
Units
%VDD
%VDD
2.6
210
mV/mT
0
100
%VDD
0
100
%VDD
2300
ppm / °C
1st
TempCo
order
0
Table 4: Programming Range Specifications
8 Timing Specifications
DC operating parameters at VDD = 5V (unless otherwise specified) and for TA as specified by the temperature
range (E or L).
Parameter
Symbol
Test Conditions
Min
Typical Max
Units
Power On Delay
TPO
FILTER = 0, RG = 0
0.4
0.8
ms
FILTER = 0, RG = 15
0.6
1.2
ms
FILTER = 15, RG = 0
1.1
2.2
ms
10
ms
FILTER = 15, RG = 15
5
Step Response Time
RG = 0 to 3, FILTER = 0
RG = 4 to 7, FILTER = 0
RG = 8 to 11, FILTER = 0
RG = 12 to 15, FILTER = 0
Table 5: Timing Specifications
24
48
100
200
32
64
132
264
µs
µs
µs
µs
9 Accuracy
DC operating parameters at VDD = 5V (unless otherwise specified) and for TA as specified by the temperature
range (E or L).
Parameter
Symbol††
Test Conditions
Min
Typical Max
Units
∆TVOQ
VOQ = 2.5V(1), 25°C / 150°C
Thermal Voq Drift
- 0.2
+ 0.2
%VDD
VOQ = 2.5V(1), 25°C / -40°C
- 0.4
+ 0.4
%VDD
∆L∆TVOQ
Life Time Drift of the Thermal
- 0.2
+ 0.2
%VDD
Voq Drift
∆L∆VOQ
Life Time Voq Drift
- 0.3
+ 0.3
%VDD
∆L∆S
Life Time Sensitivity Drift
-1
+1
%
0 to 500 ppm / °C
± 100 ppm / °C
Sensitivity Temperature
TCs
†
Coefficient
500 to 1200 ppm / °C
± 150 ppm / °C
1200 to 2300 ppm / °C
± 200 ppm / °C
∆TTC
ppm / °C
Thermal Drift of Sensitivity
VA-package
150
Temperature Compensation
GO-package
250
Thermal Drift Output Clamping ∆TVOUTCLAMP
- 0.4
+ 0.4
%VDD
Levels
Life Time Drift Output Clamping ∆LVOUTCLAMP
- 0.2
+ 0.2
%VDD
Levels
Linearity error
Le
0.2
%
Table 6: Accuracy Specifications
3901090251
Rev 012
Page 7 of 20
Data Sheet
Apr/12
MLX90251
Programmable Linear Hall Effect Sensor
†
Valid for Rough Gain within the specified option code.
∆L = Life Time Drift (based on HTOL data [1000 hours @ 150°C]).
∆T = Thermal Drift.
(1) For other test conditions, please contact the Melexis Sales representative of your area.
††
10 Programmable Features
The MLX90251 has many programmable features for adjusting the output characteristic. The features are
utilized by writing data into the redundant non-volatile EEPROM. Below is a quick list and description of all
the programmable parameters. Many of the parameters are set by Melexis and they are not used by the end
customer. Later sections of the data sheet give details on how the parameters are used.
Parameter
Internal Bias Point
Symbol
AGND
Description
Coarse adjustment of VOQ.
Analog Clock Choice†
CKANACH
Adjustment for amplifier clock generator.
2
Preset
Clamping High
CLAMPHIGH Adjustment of upper output clamping voltage.
10
512
Clamping Low
CLAMPLOW Adjustment of lower output clamping voltage.
10
512
CUSTID
Open bits for customer’s ID programming.
24
Preset
Customer
Offset
ID††
Drift†
Number of Bits Default
10
Trimmed
DRIFT
VOQ temperature drift compensation.
4
Trimmed
EEPROM Fault Level
FAULTLEV
Output state for EEPROM parity error.
1
0
Fine Gain
FG
Fine adjustment for Sensitivity.
10
0
Filter
FILTER
Adjustment for low pass output filter.
4
0
Invert Slope
INVERT
Sensitivity polarity selection.
1
0
Memory Lock
MEM_LOCK Used to lock the entire EEPROM.
1
0
Melexis
ID†
MLX_ID
Melexis IC identification number.
Melexis
Lock†
MLX_LOCK
Used to lock Melexis area of the EEPROM.
Output
Driver†
Preset
1
0
MODE
Adjustment for output stage amplifier.
2
1
OFFSET
Fine adjustment of VOQ.
10
0
OSCADJ
Chip oscillator frequency adjustment.
4
Preset
EEPROM Parity
PARITY
Ensures the integrity of the EEPROM data.
3
Calculated
Rough Gain
RG
Rough adjustment for Sensitivity.
4
0
Slow†
SLOW
Amplifier speed adjustment.
1
Preset
Temperature
Compensation Window
TCW
Range adjustment for Sensitivity Temperature
Compensation.
3
0
Temperature
Compensation
TC
Fine adjustment of Sensitivity Temperature
Compensation.
5
0
2nd Order Temperature
Compensations
TC2
Linearization adjustment of the Sensitivity
Temperature Compensation.
Table 7: Programmable Parameters
6
0
Offset DAC
Oscillator
Adjust†
†
Melexis parameter adjusted at final test.
Not included in redundant area of the EEPROM.
††
3901090251
Rev 012
Page 8 of 20
Data Sheet
Apr/12
MLX90251
Programmable Linear Hall Effect Sensor
10.1 Output Quiescent Voltage (VOQ)
Two parameters, AGND and OFFSET, are used for adjustment of the VOQ. The AGND is a 10 bit parameter
for coarse adjustment of VOQ. It has a resolution of approximately 0.014V and a range of -100%VDD to
200%VDD. The OFFSET is a 10 bit parameter with a resolution of approximately -0.005V. The OFFSET
parameter is used for fine adjustment of the VOQ, while the AGND parameter is used to set the range. The
large adjustable range allows the MLX90251 to be used in an unipolar magnetic system without limiting the
output voltage span. The formula below shows how the AGND and OFFSET parameters combine to set the
VOQ.
 14.25V
  5.0V

VOQ = −0.75V + 
∗ AGND  +  −
∗ OFFSET 
 1023
  1023
 VDD =5.00V
This formula approximates the typical VOQ of the MLX90251. The actual VOQ formula varies slightly from chip
to chip. Melexis calibrates the AGND setting during final test so that the VOQ is approximately 50%VDD with
OFFSET set to 512. This gives the VOQ a range of 0%VDD to 100%VDD without adjusting the AGND value.
The OFFSET parameter is often used to set the offset in the application's output transfer characteristic.
10.2 Thermal VOQ Drift (DRIFT)
The Thermal VOQ Drift is tuned using 4 bits. This parameter, DRIFT, is calibrated for each unit by Melexis
during final test. The value is set to achieve a VOQ accuracy below 10mV over a temperature span of 25°C to
150°C. This parameter is not used by the end customer.
10.3 Sensitivity, Rough Gain and Fine Gain
The Sensitivity of the MLX90251 is controlled through parameters linked to dedicated internal amplification
stages. The parameter Rough Gain (RG), or pre-amplifier, has 4 bits for adjustment of two stages. The two
MSB affect the Differential Input Differential Output (DIDO) stage. The two LSB effect the Differential to
Single output (DTS) stage. The gain of both the DIDO and DTS are multiplied to get the total RG. The table
below shows the theoretical small signal amplifier gain vs. the parameter RG. The pre-amplifier is chopper
stabilized and the refresh frequency is adapted automatically to the RG setting to match the chopper gainbandwidth product.
Rough Gain (MSB LSB)
DIDO
DTS
Gain
00 (00 00)
16
1.0
16
01 (00 01)
16
1.5
24
02 (00 10)
16
2.33
37
03 (00 11)
16
4.0
64
04 (01 00)
39
1.0
39
05 (01 01)
39
1.5
59
06 (01 10)
39
2.33
91
07 (01 11)
39
4.0
156
08 (10 00)
82
1.0
82
09 (10 01)
82
1.5
123
10 (10 10)
82
2.33
191
11 (10 11)
82
4.0
328
12 (11 00)
205
1.0
205
13 (11 01)
205
1.5
308
14 (11 10)
205
2.33
477
15 (11 11)
205
4.0
820
Table 8: MLX90251 Rough Gain Small Signal Amplifier Gain
3901090251
Rev 012
Page 9 of 20
Data Sheet
Apr/12
MLX90251
Programmable Linear Hall Effect Sensor
The MLX90251 also has an additional stage, Fine Gain, for fine tuning the Sensitivity. The stage (parameter
FG) follows the RG and provides a 10 bit adjustment. The small signal gain of the FG is within 1.0 and 2.5.
The RG and FG parameters are adjusted in the application to calibrate the device's sensitivity (gain) and
output slope transfer characteristic. The function for the fine gain is given in the following equation:
1
Fine Gain =
1 − 0.6 *
FG
1023
Note. The one bit parameter INVERT is used to fix the “sign” of the sensitivity. A value of 0 makes the
Sensitivity positive and the output voltage increases in response to a South magnetic field. A value of 1
makes the Sensitivity negative and the output voltage decreases in response to a South magnetic field.
Refer to section 10.5, Sensitivity Polarity, for more information on INVERT.
10.4 Sensitivity Range Selection
Each unit is characterized over temperature during final test to optimize its performance and accuracy. To
achieve the best possible Sensitivity Temperature Compensation, TempCo, each unit is optimized for use
within a specific Sensitivity range. This is represented in the ordering information by the option code. There
are four available ranges, option codes 0, 1, 2 and 3. The option code corresponds with the two MSB of the
RG parameter. Each device is tested to meet the TempCo specification in the Sensitivity range determined
by the RG parameter (RG = 0...3, RG = 4…7, RG = 8…11 or RG = 12…15), regardless of the FG parameter.
Option Code
xxx-000
xxx-100
xxx-200
xxx-300
Rough Gain
Sensitivity Range
Typical Magnetic Field Range
(mV/mT)
(mT, BMAX - BMIN)
0-3 (00 xx)
2.6 < S < 15
333 < B < 800
4-7 (01 xx)
10 < S < 35
156 < B < 333
8-11 (10 xx)
18 < S < 90
62 < B < 156
12-15 (11 xx)
50 < S < 210
6 < B < 62
Table 9: Optimized Sensitivity Range
The next figures show the typical Sensitivity versus the FG and RG parameters. The gray areas are
representative of the chip to chip dispersion (i.e.: for the same RG and FG parameters, the Sensitivity can
vary from chip to chip). There is a large overlap between the different ranges for use of one range for
applications with large magnetic and/or mechanical dispersions. The Sensitivity graphs and tables can be
used to select the right device type for the application. If one is unsure of the applications magnetic design
and the desired Sensitivity range Melexis recommends option code 2.
3901090251
Rev 012
Page 10 of 20
Data Sheet
Apr/12
MLX90251
Programmable Linear Hall Effect Sensor
Figures 10.4-1…10.4-4 Sensitivity versus RG and FG
3901090251
Rev 012
Page 11 of 20
Data Sheet
Apr/12
MLX90251
Programmable Linear Hall Effect Sensor
10.5 Sensitivity Polarity (INVERT)
The slope transfer characteristic defines the Sensitivity. The INVERT parameter changes the Sensitivity's
polarity, or the slope's direction. This allows the device to accommodate the application requirements and
the magnet's polarity. The slope is inverted in the first stage of the IC, at the Hall plate. With INVERT set to 0,
the output voltage increases as a South magnetic field is applied and decreases in the presence of a North
magnetic field. An INVERT value of 1 causes the output voltage to increase in the presence of a North
magnetic field and decrease in the presence of a South magnetic field. The magnetic field polarity is
referenced to the field component perpendicular to the top-face of the MLX90251.
10.6 Clamping Levels (CLAMPLOW, CLAMPHIGH)
Two independent values, called the clamping levels, can limit the output voltage range or swing. The
CLAMPLOW parameter adjusts the minimum output voltage level, ClampLo. The CLAMPHIGH sets the
maximum output voltage level, ClampHi. Both parameters have 10 bits of adjustment with a resolution of
approximately 0.005V. The formulas below give a close approximation of the output clamp voltage. The
actual clamping level formulas vary slightly from chip to chip. If CLAMPLOW exceeds CLAMPHIGH the
output voltage is fixed at the high clamp voltage level. The CLAMPHIGH and CLAMPLOW have an initial
value of 512, set by Melexis. This results in a fixed output voltage of approximately 50% VDD.
ClampLo =
5.10V
∗ CLAMPLOW
1023
V DD = 5.00V
ClampHi =
5.10V
∗ CLAMPHIGH
1023
V DD = 5.00V
At the point the output voltage switches between the linear operating region and the clamping region the
output can deviate slightly. This is represented by the grey areas in the figure below. The limits for deviation
in the Y axis are listed in Table 10. The deviation in the X axis is calculated from the application's transfer
function. The Clamp Comparator Offset does not affect the output linearity or clamp voltage accuracy.
During calibration it is recommended to set the clamp voltage outside of the transition region (0V to 5V).
VOUT
CLAMP HIGH
Linear Operating
Region
CLAMP LOW
Transition Point
FIELD
Figure 10.6 Output Voltage Clamping Deviation
DC operating parameters at VDD = 5V (unless otherwise specified) and for TA as specified by the temperature
range (E or L).
Parameter
Clamp Comparator Offset
3901090251
Rev 012
Symbol
Test Conditions
Min
Typical Max
CLAMPOFF
- 0.7
+ 0.7
Table 10: Clamp Comparator Offset Specification
Page 12 of 20
Units
%VDD
Data Sheet
Apr/12
MLX90251
Programmable Linear Hall Effect Sensor
10.7 Filter (FILTER)
The MLX90251 includes two programmable low-pass filters located within the chopper amplifier stages. The
two low-pass filters are controlled through a 4 bit parameter, FILTER. The FILTER value 0 corresponds to
minimum filtering, maximum speed (impulse response time), and maximum output noise. The value 15
provides the maximum filtering, minimum speed, and minimum output noise. It is important to note the noise
is also linked to the gain settings. The FILTER parameter needs to be adjusted to achieve optimal
performance. The next table shows typical values the cut-off frequency at -3 dB versus FILTER and RG
parameters. FILTER values from 8 to 11 are not used. For most applications FILTER values 7 or 15 are
recommended.
Cut-off frequency at -3 dB (Hz) – Typical
Filter
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
MLX90251-0
Rough Gain 0…3
22900
19500
12300
10400
7450
5850
5700
5050
MLX90251-1
MLX90251-2
MLX90251-3
Rough Gain 4…7 Rough Gain 8…11
Rough Gain 12…15
14300
7000
3850
11450
5550
2950
10000
3000
2300
6750
2100
1100
3900
1500
850
2900
1125
860
2700
1350
715
2550
1380
650
Not used
Not used
Not used
Not used
2200
840
565
250
1000
480
470
190
920
380
290
155
800
330
250
135
Table 11: Cut-off Frequency versus FILTER and RG Parameters
10.8 Sensitivity Temperature Compensation (TC, TCW, TC2)
The change in the device's Sensitivity versus temperature is defined as the Sensitivity Temperature
Compensation, TempCo. In an application the slope output transfer characteristic is often affected by
temperature. Fluctuations in temperature can cause variations in the air gap, mechanical alignment and
magnetic field. The Sensitivity Temperature Compensation feature compensates for these effects.
2
Three parameters, TC, TCW, TC are used for adjustment of the TempCo. The TCW is used to adjust the
2
TempCo range, TC is for fine adjustment of the TempCo value, and TC effects the TempCo linear response.
To simplify use of these parameters Melexis stores a look up table within the EEPROM of each device. The
look up table is optimized for each device by characterizing the unit over temperature at final test.
The value of TempCo is often determined by the magnet. In the application the TempCo is adjusted to
compensate for the temperature coefficient of the magnet. To adjust the value the look up table is read from
the device. The parameters are then calculated to match the desired value. The Melexis PTC hardware and
software tools contain built in functions for programming the TempCo.
3901090251
Rev 012
Page 13 of 20
Data Sheet
Apr/12
MLX90251
Programmable Linear Hall Effect Sensor
TempCo Range (ppm / °C)
Accuracy (ppm / °C)
0 to 500
± 100
500 to 1200
± 150
1200 to 2000
± 200
Table 12: TempCo Accuracy
Note: The budget error of the whole system, the compensation mismatch (system Vs. IC) tolerance should be
taken into consideration during the design. Table 11 is valid for Rough Gain within the specified option code.
See section 10.4 for information on selecting the option code.
10.9 Diagnostic Output Level (FAULTLEV)
The MLX90251 EEPROM memory content is secured through a parity check. This self-diagnostic feature
brings the output to a defined range in case of a parity error. The parameter, FAULTLEV, is used to define
the parity error diagnostic state. With the FAULTLEV set to 0 a parity error event will result in an output
diagnostic voltage low. With the FAULTLEV set to 1 a parity error event will result in an output diagnostic
voltage high. To get rid of the output load influence the output diagnostic voltage level can be fixed to either
Ground (to be used with pull-down load) or VDD (to be used with pull-up load). Melexis PTC software and
hardware tools have built in functions for calculating and programming the parity.
Note: The MLX90251 EEPROM is also redundant. Each parameter bit is written in three separate cells and a
“majority voting” is applied to determine its status. A parity error is detected only if two out of the three cells
unexpectedly change state. The bits available for the customer ID are not redundant.
10.10 The EEPROM, Parity, and Melexis CRC
The memory cells of the EEPROM are arranged in a table of four columns and one hundred twenty eight
rows. This configuration gives redundancy to the parameters stored in the EEPROM. Each parameter bit is
written in three separate cells in an individual row. A majority voting applied to the three cells determines the
logic status of the bit.
A parameter bit only toggles state in error if two out of three memory cells, within a row, unexpectedly
change. If this happens the feature, PARITY, forces the output voltage to the FAULTLEV diagnostic level.
This ensures the device does not operate with a critical memory fault.
The remaining memory cells are used for data storage. The status of these cells does not effect the device
operation. For example the Customer ID, CUSTID, is stored in this area. Melexis stores the device ID
information, TempCo look-up table and CRC bits in the extra cells. The CRC bits ensure the integrity of the
Melexis data.
Note: To avoid parity and CRC errors, the entire contents of the EEPROM must be read before
programming. Melexis PTC software and hardware tools have built in functions for reading the EEPROM and
handling parity.
10.11 Output Amplifier Configuration (MODE)
The output buffer can be configured to accommodate capacitive loads and improve the saturation voltage
(output swing). The two bit parameter, MODE, sets the current capacity of the output amplifier. Melexis sets
this parameter to 1 at final test. This parameter is not used by the end customer.
10.12 Memory Lock (MEMLOCK)
The Memory Lock feature prevents the device from entering programming mode and from any changes to the
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EEPROM. The entire EEPROM is locked by setting the MEMLOCK parameter to 1. This should be the last
parameter set in the application.
10.13 IC traceability
A unique ID number is programmed into the EEPROM of every IC. The ID number gives Melexis additional
traceability to better service its customers. The ID number is composed of the lot number, wafer number, and
wafer coordinates (X and Y). Memory is also available for the customer to add a serial number of the product
or any other data.
11 Performance Graphs
Typical IDD VS VDD
Typical I DD VS VDDNOM
60
8.5
20
8
Over Voltage
40
V DDNOM
7.5
Under Voltage
IDD (mA)
I DD (mA)
7
0
-20
6.5
6
-40
5.5
150°C
-40°C
25°C
-60
-80
-10
0
10
20
150°C
-40°C
25°C
5
30
VDD (Volts)
4.5
4
4.5
5
5.5
6
VDD (Volts)
Figure 11-1…11-2 IDD Versus VDD
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12 Applications Information
12.1 Application Circuits – VA-package
Pin 2, TEST, is not used in applications. For EMC protection it is recommended to connect pin 2 to pin 3,
Ground, as close as possible to the device pins. The values for capacitors, C1 and C2, can be adjusted to
satisfy ESD and EMC requirements according to the environment. Ceramic capacitors are recommended for
use in the application. However for stable operation, the global output capacitor (C2 + C3) should not be
higher than 150nF.If higher capacitors (due to special ESD or EMC requirements) or special circuit
configurations are requested, please contact Melexis.
The MLX90251 can operate with a high impedance load and C2, a load resistor is not required.
Figures 12.1-1…12.1-2 Application Circuits
A voltage of 9V is required on VDD for programming. All additional components connected to VDD must be
able to withstand the voltage. The MLX90251 is designed for operation with a stable 5V supply. If fast
voltage transients occur additional filtering may be required.
12.2 Programming the Sensor
To program the MLX90251 connection to VDD, GND, and VOUT is required. The device is placed into program
mode by increasing the supply voltage to the VDD program level. In program mode data is clocked into the
device through the output pin using the Melexis tri-level PTC protocol. The clock and data are integrated into
one serial data stream, eliminating the need for a dedicated clock signal. The data is clocked at the leading
edge of each bit.
5.0V
VOUT
Program Wave Form
2.5V
0V
Device
Decoded
Clock
Device
Decoded
Data
Figure 12.2-1 VDD Programming Level
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X
0
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Figure 12.2-2 Tri-Level PTC
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Note: External capacitors and resistors will effect the rise and fall times for the programming waveforms.
Program pulse timings may require adjustment for the application. The device can not be programmed if
MEMLOCK equals 1.
The EEPROM contents can be read from the device. This procedure, known as a read back, is done by
sending a read command and then measuring the supply current. To successfully read the EEPROM it must
be possible to measure the supply current to the device. The Melexis PTC hardware and software tools
contain built in functions for reading the EEPROM.
The MLX90251 can be programmed by using the PTC-04 programmer and the dedicated software tools. The
timing and voltage levels are controlled through the programming hardware and software. Further details can
be found in the MLX90251 software documentation.
12.3 Calibration Procedure
The programmable features of the device allow for calibration within the application. This section gives
general information for a two point calibration procedure. The two point calibration is the most common
however, it is possible to adapt other procedures.
1.) The first step in the calibration procedure is to initialize the device. This is done by establishing
communication and reading the contents of the EEPROM.
2.)The second step is to set the TempCo and FILTER settings.
3.) Step three is the evaluation of position one. During this step the output voltage is measured with initial
values for RG, FG and OFFSET.
4.) Step four is the evaluation of position two. During this step, the output voltage is measured with the same
values from step 3. From the measurements it is possible to calculate the slope and offset error. Next the
output slope transfer characteristic versus FG and RG is interpolated. With this information the initial settings
are adjusted and the output voltage is measured again.
5.) Step five is the final check and adjustment. At this stage small corrections are made to the OFFSET and
FG parameters. Next, the output clamping parameters, CLAMPHIGH and CLAMPLOW, are determined.
6.) The sixth step is the program phase. Now that all the parameters are determined and the application
requirements are satisfied, the settings are programmed into the EEPROM.
7.) The final step, seven, is the lock and verify step. Here the customer can perform any number of additional
measurements and verify the EEPROM contents. After this is completed the MEMLOCK is set and the
EEPROM is locked, preventing any further programming.
Note: EEPROM verification is done by reading the contents of the EEPROM and comparing it to the data
written. It is possible to read the EEPROM contents regardless of the status of MEMLOCK.
The Melexis PTC software tools contain built in functions and procedures for calibrating the MLX90251.
Please refer to the software documentation for more information on how to use the calibration tools.
The output of the MLX90251 is ratiometric. To avoid calibration errors from fluctuations in the supply voltage,
the output voltage should be measured as a percentage of the supply voltage.
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13 Standard information regarding manufacturability of Melexis
products with different soldering processes
Our products are classified and qualified regarding soldering technology, solderability and moisture sensitivity
level according to following test methods:
Reflow Soldering SMD’s (Surface Mount Devices)
•
•
IPC/JEDEC J-STD-020
Moisture/Reflow Sensitivity Classification for Nonhermetic Solid State Surface Mount Devices
(classification reflow profiles according to table 5-2)
EIA/JEDEC JESD22-A113
Preconditioning of Nonhermetic Surface Mount Devices Prior to Reliability Testing
(reflow profiles according to table 2)
Wave Soldering SMD’s (Surface Mount Devices) and THD’s (Through Hole Devices)
•
•
EN60749-20
Resistance of plastic- encapsulated SMD’s to combined effect of moisture and soldering heat
EIA/JEDEC JESD22-B106 and EN60749-15
Resistance to soldering temperature for through-hole mounted devices
Iron Soldering THD’s (Through Hole Devices)
•
EN60749-15
Resistance to soldering temperature for through-hole mounted devices
Solderability SMD’s (Surface Mount Devices) and THD’s (Through Hole Devices)
•
EIA/JEDEC JESD22-B102 and EN60749-21
Solderability
For all soldering technologies deviating from above mentioned standard conditions (regarding peak
temperature, temperature gradient, temperature profile etc) additional classification and qualification tests
have to be agreed upon with Melexis.
The application of Wave Soldering for SMD’s is allowed only after consulting Melexis regarding assurance of
adhesive strength between device and board.
Melexis is contributing to global environmental conservation by promoting lead free solutions. For more
information on qualifications of RoHS compliant products (RoHS = European directive on the Restriction Of
the use of certain Hazardous Substances) please visit the quality page on our website:
http://www.melexis.com/quality.aspx
14 ESD Precautions
Electronic semiconductor products are sensitive to Electro Static Discharge (ESD).
Always observe Electro Static Discharge control procedures whenever handling semiconductor products.
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15 Package Information
VA-package: the lead-free VA-package is released for MSL1/245°C.
15.1 VA Package Outline and Hall Plate Position
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16 Disclaimer
Devices sold by Melexis are covered by the warranty and patent indemnification provisions appearing in its
Term of Sale. Melexis makes no warranty, express, statutory, implied, or by description regarding the
information set forth herein or regarding the freedom of the described devices from patent infringement.
Melexis reserves the right to change specifications and prices at any time and without notice. Therefore, prior
to designing this product into a system, it is necessary to check with Melexis for current information. This
product is intended for use in normal commercial applications. Applications requiring extended temperature
range, unusual environmental requirements, or high reliability applications, such as military, medical lifesupport or life-sustaining equipment are specifically not recommended without additional processing by
Melexis for each application.
The information furnished by Melexis is believed to be correct and accurate. However, Melexis shall not be
liable to recipient or any third party for any damages, including but not limited to personal injury, property
damage, loss of profits, loss of use, interrupt of business or indirect, special incidental or consequential
damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical
data herein. No obligation or liability to recipient or any third party shall arise or flow out of Melexis’ rendering
of technical or other services.
© 2012 Melexis NV. All rights reserved.
For the latest version of this document, go to our website at
www.melexis.com
Or for additional information contact Melexis Direct:
Europe, Africa, Asia:
Phone: +32 1367 0495
E-mail: [email protected]
America:
Phone: +1 248 306 5400
E-mail: [email protected]
ISO/TS 16949 and ISO14001 Certified
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