|
|
MLX90308
Programmable Versatile Sensor Interface
 Download MLX90308 Datasheet (PDF)
Subscribe To Updates
MLX90308 General Description
The MLX90308 is a dedicated microcontroller which performs signal conditioning for sensors wired in bridge or differential configurations.
Sensors that can be used include thermistors, strain gauges, load cells, pressure sensors, accelerometers, etc. The signal conditioning includes gain adjustment, offset control, high order temperature and linearity compensation.
Compensation values are stored in EEPROM and are re-programmable. Programming is accomplished by using a PC, with an interface circuit (level shifting and glue logic), and provided software.
The application circuits can provide an output of an absolute voltage, relative voltage, or current. The output can be range limited with defined outputs when the signal is beyond the programmed limits. Other features include alarm outputs and level steering.
The robust electrical design allows the MLX90308 to be used where most signal conditioning and sensor interface circuits cannot be used. Voltage regulation control is provided for absolute voltage and current modes (external FET required).
The standard package is a plastic SO16W. The device is static-sensitive and requires ESD precautions.
For further information, please contact:
Laurent Otte, lot@melexis.com
MLX90308 Features and Benefits
- Microprocessor-controlled signal conditioning for bridge-type sensors
- Suited for low-cost sensors: reduction of non-linearity by programmable coefficients External or internal temperature sensor for compensating temperature errors
- Versatile output signal ranges: 4, 5, 10, or 11VDC; 4 to 20 mA loop
- Mass calibration easy with 2400 or 9600 baud UART
- Power supply from 6 to 35VDC
MLX90308 Tools
| Software & Tools |
File Type |
Size |
Revision |
Date |
Action |
| SW90308_90314 |
EXE |
220.0 KB |
2 |
6/5/2008 |
|
MLX90308 Environmental Information
This text will be replaced
MLX90308 Frequently asked Questions
Programmable Hall Sensors
Question
Thanks for the info. I agree the evaluation kit is a good idea for an old dog like me. I also read a bit of info on Melexis's sensor interface, and even though there is alot of digital talk, it seems there is an analog input and an analog output, which is what I am used to dealing with. I think this "out of the box" eval kit might be just the "bridge" I need to get me across the technology gap. A similar exrcise can be done for a strain guage pressure sensor with the MLX90308 compared to a series of instrumentation amplifier cirucits that would correct for the non-linearities of the pressure transducer over span and also due to temperature.
MLX90308 D High Temp linearity
Question
Has anyone noticed a change in the high temperature performance of the new version D of the MLX90308/90314? I'm observing a non-linearity in the low range (0-10% of full scale), at temperatures 110C - 140C. I'm not seeing this with our older "CA" chips. The sensors we use aren't the source of it (I checked). If I'm the only one with this problem - maybe I should reevaluate my design. Do you have any thoughts on what pins might be sensitive to component selection (sensor ~1-2kohm, 0.1 to 4.7uF bypass capacitors, ESD protection, etc.)?
I am in absolute mode. The output load is a 0.1uf cap, 11V zener diode, and DVM in parallel, all to ground. I used the same application circuit for CA and DA, but now I've removed the 5k resistor recommended in your application circuit - this helped remove some high-temperature non-linearity.
MLX90306
Question
SW90308 allows the user to program integrated EEPROM of MLX90308D, but it seems unable to program MLX90308CA.
Answer
The SW90308 allows to program both the MLX90308DA and MLX90308CA. To solve communication problems with the CA you can do the following: - use a non standard baud rate for the communication. - copy the EEPROM contents of the address 32 to 34 (CLKTC parameter) stored on a chip that shows no communication problems to the chip giving troubles. - disable the turbo bit.
MLX90308
Question
I am trying to determine if I can use the MLX90308 with a load cell. The cell is a 350ohm cell with 2mV/V output at full scale. Ideally I will use the device in current mode. Is this the correct device?
Answer
First you need to determine what supply voltage you expect for your load cell. With the MLX90308 you will supply your cell with 5V and it will take too much current with a 350ohm cell. The MLX90314 is the same as the MLX90308 besides that it has a much higher gain (2625mA/V max).
Production Level Calibration Software
Question
We are preparing for production with MLX90308 based 4-20mA sensors. We are looking for production level calibration software which will allow calibration of 10 x sensors at the same time. Basically we like to bring 10 x sensors to low pressure, set Zero than bring the whole manafold to High pressure and set Span. Does anyone developed MLX90308 calibration software which can handle 10 x sensors at the same time?
MLX90308 9n Digital Current Mode
Question
I cannot get MLX90308 to Operate in Digital Current Mode. It works OK in Analog Current or in Digital Voltage but when I change from Analog Current to Digital Current I get no signal on CMO pin. When I look at Signal In Value everything appears OK. Also if I enable both Current and Voltage Mode (which is allowed in Digital Mode) again VMO pin responding but not CMO pin. I am using MLXconfig 1.e as software.
Answer
We have a dll available for both MLX90308 and MLX90314 which you can use to build up your own calibration algorithm. By using this you can significantly decrease the calibration time.
Buy MLX90308
|
|