MELEXIS MLX90255LUF-4

MLX90257
Relative Integrated Pressure Sensor
Features and Benefits
Relative Integrated Pressure sensor
Less than ±1% error range overall
Programmable through the connector (3 pins)
Trimmable offset and sensitivity
On-Chip Signal Conditioning
Output proportional to the applied pressure
Ratiometric output
Rail-to-rail output
Diagnostics of broken supply wires and broken sensor
Output protected against short-circuits at both battery terminals
Different pressure ranges available
Application Examples
Medical diagnostics
Pumps
Industrial applications
Robotics
Ordering Information
Part No.
MLX90257
MLX90257
Temperature Suffix
L (-40°C to 150°C)
L (-40°C to 150°C)
Package Code
UF (die on foil)
UF (die on foil)
Option
-2
-4
Description
3 to 7 Bar Full Scale
15 to 30 Bar Full Scale
1. Functional Diagram
2. Description
VDD
Chopper
demodulator
Temperature
sensor
ADC
Gain
calibration
DAC
DIGITAL CORE
Diagnostics
OUT
The MLX90257 is an integrated
relative pressure sensor (2
pressure ports) realized in
CMOS technology with
micromachining options. It
consists of an analog signal
chain that interacts with the
digital core and on-chip
temperature sensor in order to
provide uniform overall sensing
characteristics after calibration
and to cancel the temperature
related parameter drifts.
The output is proportional to the applied pressure with an adjustable slope and offset. It is ratiometric and
goes rail-to-rail with a 3mA source and sink capability. Different pressure ranges are available (from 1.2 to
10 Bar full scale ranges, see above ordering information).
3901090257
Rev. 006
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Data Sheet
Mar/08
MLX90257
Relative Integrated Pressure Sensor
TABLE OF CONTENTS
1.
FUNCTIONAL DIAGRAM...................................................................................................................... 1
2.
DESCRIPTION....................................................................................................................................... 2
3.
ABSOLUTE MAXIMUM RATINGS ....................................................................................................... 3
4.
MLX90257 ELECTRICAL SPECIFICATIONS ...................................................................................... 3
5.
GENERAL DESCRIPTION .................................................................................................................... 4
6.
UNIQUE FEATURES ............................................................................................................................. 4
7.
PERFORMANCE GRAPHS................................................................................................................... 5
8.
APPLICATION INFORMATION ............................................................................................................ 6
9.
DIE DIMENSION AND PAD COORDINATES....................................................................................... 7
10. CALIBRATION AND PROGRAMMING PROCEDURE ........................................................................ 7
11. ESD PRECAUTIONS............................................................................................................................. 8
12. DISCLAIMER ......................................................................................................................................... 9
3901090257
Rev. 006
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Data Sheet
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MLX90257
Relative Integrated Pressure Sensor
3. Absolute Maximum Ratings
Parameter
Min
Max
Supply Voltage, VDD
-14V
16V
Output Voltage, Vout
-0.5V
16V
Storage Temperature Range, TS
-55°C
165°C
ESD Sensitivity (AEC Q100 002)
-2 kV
2 kV
Exceeding the absolute maximum ratings may cause permanent damage. Exposure to absolutemaximum-rated conditions for extended periods may affect device reliability.
4. MLX90257 Electrical Specifications
DC Operating Parameters TA = -40oC to 150oC, VDD = 5V (unless otherwise specified)
Parameter
Symbol Test Conditions
Min
Typ
Max
Units
OPERATIONAL FEATURES
Supply Voltage
VDD
Operating
4.5
5
5.5
V
Supply Current
IDD
VDD = 5V ± 10%, excluding
output current
4
6
10
mA
Output Current Capability
Iout
VDD = 5V
-3
3
mA
Pressure output @ zero pressure
Vout
VDD = 5V
0.46
0.5
0.54
V
Pressure output @ full scale pressure Vout
VDD = 5V
4.46
4.5
4.54
V
Low Clamping Level
Vout
5
10
% VDD
High Clamping Level
Vout
90
95
% VDD
2
% VDD
5
% VDD
DIAGNOSTIC FEATURES
Output when sensor is broken
Sensor broken
Output when VDD is broken
Pull-Up > 4.7K
Output when VSS is broken
Pull-Down > 10K
Response Time (to reach 1% error)
3901090257
Rev. 006
95
% VDD
2
Page 3 of 9
ms
Data Sheet
Mar/08
MLX90257
Relative Integrated Pressure Sensor
5. General Description
This chip integrates a pressure sensor and the associated signal conditioning on the same die. The
supply voltage VDD directly supplies the pressure sensor.
A chopped instrumentation stage amplifies the differential output signal of the sensor. The gain of this
amplifier can be adjusted with 3 bits. The input stage is followed by a differential to single-ended
conversion. The reference voltage for this stage is generated by a 10 bit DAC and varies linearly with
temperature in order to perform the offset and offset drift compensation. A digital hardware multiplier
calculates this compensation. The temperature signal, serving as input for this multiplier, is generated
from the ADC of the output signal of the internal temperature sensor.
The chopped signal is demodulated with a switched capacitor stage. The buffered output serves as
reference for a 10 bit DAC to perform the span and span drift compensation. The DAC is controlled by the
digital part.
Finally the signal is given out by a class AB rail-to-rail amplifier capable of sourcing and sinking large
currents.
A 3-point temperature and 2-point pressure calibration is required (room temperature, a low temperature
and a high temperature), to achieve an error less than ±1% over the complete pressure and temperature
range (the output error is referred to the output span).
PTC (Programming Through Connector) protocol is used to perform calibration.
6. Unique Features
Diagnostic Limits
Diagnostic of broken sensor: The output will be forced to ground (or a very low level) when the sensor
membrane breaks.
Diagnostic of broken wires: The output will be forced to ground (or a very low level) when the supply wire
breaks, even when a pull-up is still connected to the output pin.
The output will be forced to the supply voltage (or a very high level) when the ground wire breaks, even
when a pull-down is still connected to the output pin.
Output Protection
The output is protected against short-circuits at either battery terminals. The output can handle voltages
between -0.5V and 16V (independent of supply voltage).
Memlock Function
The memory consists of ZAP cells. When all calibration parameters are programmed, the chip can be
locked. This to avoid unwanted data to be written into the memory cells.
Once the chip is locked in a normal application, it is not possible to unlock.
Clamping Levels
The user can enable the clamping of the output to ensure that the output can not enter the fault band in
normal application.
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Rev. 006
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Data Sheet
Mar/08
MLX90257
Relative Integrated Pressure Sensor
7. Performance Graphs
The graphs below show measured output voltages taken at 20 differential pressure points (0 mBar to
2000 mBar between pressure ports), at 21 ambient temperature points (-50 to 150 Celsius) and with Vdd
set to 4.5 V, 5 V and 5.5 V.
Vout versus Pressure with Ta = -50..150 C
100
90
80
70
Vout %Vdd
60
50
40
30
20
10
0
0
10
20
30
40
50
60
70
80
90
100
Pressure %FS (FS = 2000 mBar)
Note : FS means Output Voltage Full Scale (4 V).
Measured Error is below 1 % of FS for all ambient temperature and pressure points (see graphs below).
Error versus Ambient Temperature with P = 0..2000 mBar
1.5
1
Error in % of FS
0.5
0
-0.5
-1
-1.5
-50
-30
-10
10
30
50
70
90
110
130
150
Ambient Temperature C
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Rev. 006
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Data Sheet
Mar/08
MLX90257
Relative Integrated Pressure Sensor
Error versus Pressure with Ta = - 50..150 C
1.5
1
Error in % of FS
0.5
0
-0.5
-1
-1.5
0
250
500
750
1000
1250
1500
1750
2000
1750
2000
Pressure mBar
4.5V and 5.5V Ratiometricity Error versus Pressure with Ta = - 50..150 C
0.5
0.4
0.3
Error in % of FS
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
-0.5
0
250
500
750
1000
1250
1500
Pressure mBar
8. Application Information
Very few off-chip components are needed (only 2 decoupling capacitors).
Only 3 pins are used (Vdd, Vss, Out), see pad layout drawing in paragraph 9.
Calibration and Programming is made through Out pin.
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Rev. 006
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Data Sheet
Mar/08
MLX90257
Relative Integrated Pressure Sensor
9. Die dimension and pad coordinates
Available upon request.
10.
Calibration and Programming Procedure
Programming in Temporary Memory
The programming is done through the connector: only the application pins (supply, ground and output)
need to be used. The programming can be enabled by forcing the supply high enough (VCC_T). Through
the OUT pin one can input the data. The data is Pulse Width Modulated.
At the end of the programming, keep OUT high until VCC has reached its normal level (VCC_N).
Thereafter disconnect OUT. The time in between should be less than 100us.
Zapping of the Permanent Memory
Only 1 bit can be zapped at a time. First program 1 bit to ‘1’. A higher supply (VCC_Z) is needed to be
able to zap the bit. The zapping is done when OUT is high (OUT_Z).
A high current will flow during the zapping. It is recommended to limit this current to 200mA.
The memlock-bit should be zapped as last bit, as this disables programming function.
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Rev. 006
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Data Sheet
Mar/08
MLX90257
Relative Integrated Pressure Sensor
In order to check zapping, one can program Test Mode 22 = 10110b. Also 1 bit of the temporary memory
should be ‘1’. If the zap cell – corresponding to the place of the ‘1’ in the temporary memory – is zapped,
then the supply current will be at least 35mA. Otherwise the supply current will be approximately the same
as in normal mode (maximum 10mA). Values in between indicate a bad zap.
Parameters
Parameter
t0n
t0p
tpz
tpn
tz0
tr
tf
trz
tfz
th0
tl0
th1
tl1
tz
tz0
td0
tdp
tuz
tun
tdz
VCC_N
VCC_P
VCC_Z
OUT_L
OUT_H
OUT_Z
Minimum
1us
2us
1us
1us
2us
0.5us
0.5us
0.5us
0.5us
50us
200us
200us
50us
5ms
100us
100us
100us
100us
5us
5us
4.5V
8V
14V
0V
4V
12V
Maximum
100us
200us
100us
100us
300us
5us
5us
15us
20us
100us
300us
300us
100us
6ms
1ms
1ms
1ms
1ms
50us
50us
5.5V
12V
16V
1V
5V
14V
Meaning
Rise Time of Supply from 0V to VCC_N
Rise Time of Supply from 0V to VCC_P
Rise Time of Supply from VCC_P to VCC_Z
Fall Time of Supply from VCC_P to VCC_N
Fall Time of Supply from VCC_Z to 0V
Rise Time of Out from OUT_L to OUT_H
Fall Time of Out from OUT_H to OUT_L
Rise Time of Out from OUT_H to OUT_Z
Fall Time of Out from OUT_Z to OUT_L
High Time for 0
Low Time for 0
High Time for 1
Low Time for 1
zap time
OUT & VCC = Z & 0V
OUT & VCC = OUT_L & 0V
OUT & VCC = OUT_L & VCC_P
OUT & VCC = OUT_H & VCC_Z
OUT & VCC = OUT_H & VCC_N
OUT & VCC = OUT_L & VCC_Z
Normal Supply
Programming Supply
Zapping Supply
Low Output
High Output
Output for zapping
An application note describes in more details this calibration procedure.
Calibration software is also available on request.
11.
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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Rev. 006
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Data Sheet
Mar/08
MLX90257
Relative Integrated Pressure Sensor
12.
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 life-support 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.
© 2002 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 and Japan:
All other locations:
Phone: +32 1367 0495
E-mail: [email protected]
Phone: +1 603 223 2362
E-mail: [email protected]
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3901090257
Rev. 006
Page 9 of 9
Data Sheet
Mar/08