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MLX90251
Programmable Linear Hall Effect Sensor
 Download MLX90251 Datasheet (PDF)
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MLX90251 General Description
The MLX90251 is a Programmable Linear Hall Effect sensor IC fabricated utilizing Silicon-CMOS technology. It 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 for even greater versatility.
The Voq (Vout @ B = 0 Gauss), sensitivity, direction of slope, the magnitude of sensitivity drift over temperature (TC - 1st & 2nd order), the clamping level, the thermal Voq drift and the bandwidth, are all programmable.
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 will not affect accuracy. When programmed for a conventional sensitivity (with a positive gain), the voltage at the output will increase as a South magnetic field is applied to the branded face of the MLX90251. Conversely, the voltage output will decrease in the presence of a North magnetic field. The MLX90251 has a very stable thermal compensation for both the sensitivity and the Voq over a broad temperature range.
MLX90251 Features and Benefits
- Analog Signal Processing
- Quad Switched Hall plate/Chopper Stabilized Amplifier
- ratiometric output Quiescent Voltage Voq
- Adjustable Sensitivity
- Adjustable Low-pass Filter
- Adjustable Output Driver Configuration
- Adjustable Clamping Voltage
- Adjustable Thermal Voq Drift
- Adjustable Sensitivity Temperature Coefficient (1st & 2nd order)
- Adjustable Internal Bias Point
MLX90251 Environmental Information
This text will be replaced
MLX90251 Frequently asked Questions
Noise Filtering for MLX90215
Answer
Low pass filter can only help and the lower the cut-off frequency, the better results you will get.
At the sensitivity range you are thinking i.e. 140mV/mT or 14 mV/G, the internal sampling frequency of the chip is already pretty low (4 kHz) and therefore a cut-off frequency of 500 Hz (or less) for your filter will be adequate to eliminate the noise components which are associated to the internal sampling.
You can also work w/ MLX90251 as this IC has also an on-chip filter you can set through the programming unit (e.g. together w/ offset and gain settings). Using the strongest filter (i.e. Filter = 15), you will already get a serious noise reduction and you may not need an external low-pass filter: a decoupling cap will be enough. Advantage of MLX90251 is that 140 mV/mT is not at the top end of its specification while MLX90215 gain settings is somewhat limited to this value.
In any case, all those filter (internal or external) considerations need to be checked vs. your bandwidth requirement for your application. If you do not have specific "speed" requirements, you have the complete freedom. If you have speed/response time/bandwidth requirements, then you need to consider those while dimensioning your filter.
Problem on PTC04 Programmer
Answer
When the MPT is started, the software automatically scans for the PTC-04 on all ports and reads the ID + Firmware version. If this fails you get the error "No Melexis Devices were found...". In your case it sound like the firmware is corrupted and does not fit with the requirements. You should try to reload the firmware and check for the “Main ID". Please use the following procedure:
- Switch OFF PTC-04 and connect RS232
- Start MPT
- Start user interface PTC-04. Press "Do not connect" in case you get a warning.
- Click on "Firmware commander"
- Switch ON PTC-04. Green LED will be ON
- Select Communication / connect / communications Port ( com x)
- Select Communication / Upload firmware and select the “ptc04_mlx90251_firmware.hex" from CD
- Select System / Main ID and click "Load". Verify the "contents of this hardware" with the "default". If it matches then the problem is solved. If it does not match click on "save defaults" and then click "load" again. If the contents still does not match the default then most likely the PTC-04 is damaged and should be send back to Melexis.
MLX90251 Problem
Question
My question regards the device MLX90251.
I use the programmer PTC-03 and the device 90251LVA-2 wich I received through your sales representative in Sweden.
Recently I received a device called 90251LVA-3(LF) and my PTC-03 does not recognize this. Can you tell me what the difference between these devices is, besides the sensitivity range (-3), and why the PTC-03 can't connect to it.
Programming MLX90251 with PTC04
Question
Hello,
I'm now using the PTC04 to program sensors MLX90251.
The dauter-board is PTC04-DB-HALL01. I cabled as follow:
1. VDD_DIE_1 connected to VDD of the sensor
2. GND_DIE_1 connected to GND of sensor
3. OUT_DIE_1 connected to Vout of sensor
There is no any other component connected to the sensor.
I'm using the connection USB between PC and mainboard.
I installed the MLX90251 UI. Actually, I can read Vdd, Idd and Vout RAM by using Measuring by RAM.
The voltage applied onto Vdd of the sensor is correctly set to 9V when passing in mode program.
However, when I begin with the first step: Read Device + Set TC, there is an error:
The device is not regconized.
Could you please tell me how to solve this problem.
Answer
Hello
The user interface of the MLX 90251 is equipped to handle the MLX 90251CC and FA.The MLX 90251 CC and FA have different read back protocols. If you want to use the MLX90251CC read back protocol, you have to select the type of device you want to use. The selection is made in the INI-file. See documantation of UI how to change the ini file.
Check the description on the package to find out which version you got. FYI : The 90251F is the leadfree version.
rg
Depoorter JC
Question
Thank you for your reply.
I checked your sensors. These are MLX90251F so the problem maybe doesn't come from the ini-files. May I not use the logfile?
I wonder if the Readback is not done completely. I mean that maybe the CRC, parity or TC-Table is not correct.
I'm now using the default settings for the MLX90251 UI but I can't pass through the first step of Solver (Read Device + Set TC).
Do you think that I have to change these settings?
Did I cable correctly the sensor to the daughter-board? To where will I connect the pin Test of the sensor?
Thank you and best regards.
Two measuring equipments on one PTC-04 programmer
Question
The PTC04_DB_Hall01_DataSheet.pdf document shows that 2 measurement instruments could be connected to the PTC-04 programmer at the same time. I use a safety-critical sensor with dual MLX90251. Can I communicate with the two chips without changing the connections from one sensor to the other? Device selector does nothing.
Answer
The second connection on the PTC04_DB_HALL01 is only used for the MLX90277. It can not be used with the MLX90251.
The device selector is a software switch. It allows you to handle more than one device with the software. There are 16 virtual devices available. Every virtual device corresponds to a single die with separate cache for the EEPROM, independent Solver settings and Solver parameters.
The hardware switch has to be done externally by a MUX or relay.
Please check the topic: "MLX90251 and PTC04" for additional information and maybe an alternative solution to your question.
MLX90251 and PTC04
Question
I am using the PTC04 and the MPT to program a MLX90251 FA sensor. I am able to start the User Interface MLX90251 FA. I am also able to switch to the UI MLX90251 CC. When I do ReadEEprom for an FA-sensor, there is an error message: "This device is not recognized. The Software is unable to program this device". Could you please tell me how to solve this problem.
Answer
First of al: Never use software for the MLX90251CC with samples of the MLX90251FA or visa versa. If you program devices with the wrong software you can make them unusable.
After Read EEPROM the software will check the EEPROM contend is valid or not. If EEPROM contend is not valid, the software returns an error message.
An unrecognised device is usually the cause of a bad connection between the PTC04 and the device. Check your connections. Perform a measure by ROM to check the IDD and the output of the device.
You can find more details on this topic in the document FAQ_PTC04. You can find this document on the CD delivered with the PTC04 or on softdist.
Question
We have got a PCT04 programmer (unit: 04060009, rev:2.3)and we want to program a MLX90251. In our sensors we use two MLX90251. The problem is the following:
We made a cable to the programmer and we tried to program the Hall cells (we tried with two sensor). While we tried to programm the Hall IC, two ICs was ruined. In the first sensor’s dead IC is the Hall 1, and in the second sensor’s dead IC is the Hall2.
After that I made a much shorter cable because our helper suggested that. I noticed the following things:
-If I used the output device A pin (application connector pin 4) the programmer was able to read the EEPROM and made measurment.
-If I used the output device B pin (application connector pin 8) the programmer was able to read the EEPROM but unable to made measurment.
-I tried to run the self test of the programmer but it was failed with Test Xram Roughly fail (bin code: 400).
-We saw the voltage level of the Hall IC’s output and supply voltage with oscilloscope when we tried to read the device. The supply voltage maximum was 9V, and the output maximum was 5V.
If you have any suggestion what should I do please write me.
Answer
1) Please let me first explain the purpose of PTC-04 and the uses for different applications / devices
- PTC-04 is a universal programming toolbox to program all current Hall sensors. A daughter board is used to create the link between the programmer and the sensor/application.
Currently we have 2 type of daughterboards : DBhall-01 ( general DB used for 90215 / 90251 / 90277 ...) and the DB-90316 ( only usable for 90316).
The DB can handle single and dual hall sensors. Single device are linked to device A and dual devices are linked to device A + B.
- The MLX90251 is a single linear hall sensor. This means it should be connected to pins of the DB hall marked as device A.
The pins marked with device B are not accessible by the software of 90251. In the user interface you will find a device selector ( device 1...16), but it is a software switch. It allows you to handle more than one device with the software. There are 16 virtual devices available. Every virtual device corresponds to a single die with separate cache for the EEPROM, independent Solver settings and Solver parameters. The hardware switch has to be done externally by a MUX or relay.
- The MLX90277 is a dual programmable hall sensor, which is equal to 2 dies in 1 TSSOP package. They should be connected as device A + device B. The software of 90277 can handle 8 virtual devices in case an external multiplexer is used.
2) in your application you use 2 x 90251, but for us this is 2 x a single hall sensor and therefore handled as device 1 and device 2.
Even if you connect the second 90251 to device B of the DBhall-01, the software will only measure + communicate with the sensor connected to device A. This explains why you think that you can read the EEPROM of the second 90251, but not see any response or changes in the measurements.
If you compare the EEPROM contents of the 2 devices , then you will notices that they are exactly the same, even the unique Melexis ID.
According to me your you have programmed 2 times the same device, but the second time with wrong solver information and therefore the output will not be as expected. The devices are not damaged and can be reprogrammed if there were not locked.
3) The supply voltage level of 90251 can be 0 / 5 / 9V. 5V is the normal operating voltage and used during measurements. 9V is applied during communication. 0V is selected for resetting the device.
4) The error message that you get during the self test of PTC-04 is not critical and is not related to the mentioned issue. The function that has been tested and reported as fault is currently not used. This error message has been noticed before by Melexis but was related to a software bug. Please check that the latest UI and PSF is installed.
5) In case you want to use 2 x 90251 without an external multiplexer or without manually switching the connector, you could use the 90277 software and connect the 2 x 90251 as a dual sensor , connected to device A and Device B. BUT you can only do this if the VDD is separated, this implements that you have 5 or 6 cables and did not use a common VDD.
( the dual sensor is used for redundancy and implements that everything is separated. 2 x Vdd + 2 x Vout + 2 Vss. A common Vss is acceptable, but not a common Vdd)
Question
First of all thanks for the fast reaction.
If I tried only with output device A pin (application connector pin 4) to connect the MLX90251 the connection was succesfull and the programmer read out the EEPROM but with a error massage, and it was unable to programm the sensor. The UI said : Device is not recognized. The Software is unable to program the device. Do you have any suggestion what should I do?
Answer
The curreent version of the UI for 90251 can support 2 types: 90251CC and 90251FA. To change the type you have to modify the ini file and restart the program. ( please check the dokumenttion how to change the ini file)
By default the software starts for 90251CC.
Never use software for the MLX90251CC with samples of the MLX90251FA or visa versa. If you program devices with the wrong software you can make them unusable.
That is why you get an error like "Device is not recognized. " when the wrong type is selected.
Best regards
Depoorter JC
Programming MLX90251 FA
Question
I need to programm a MLX90251 FA sensor using the MPT. In a first step I use the Solver to programm the angle range, the voltage range and the clamps. The filter value is set to 0. I disconnect the sensor from the PTC and do some measurements.
Then I need to change the filter value, for example to 15. Thus I connect the sensor to the PTC again.
My problem is: Do I have to use the Solver again and evaluate the positions again, or is it possible to use the "Program EEprom" switch?
I tried using the "Program EEprom", and this destroyed the sensor.
measuring range of 5000 Gauss
Question
the MLX90251LVA-3 (i.e. Option Code 3) could be an option for you. This chip is a programmable Linear Hall Effect Sensor with Ratiometric Output voltage, which allows to measure magnetic fields up to 5000Gauss (=500mT) and even more.
MLX90251FA EEPROM Parity
Question
I'm using a PTC-03 with firmware revision 1.64 and UI software revision 1.3 to program MLX90251FA hall-effect sensors. Somehow, it appears that I've programmed one sensor with invalid memory contents (oops...I suppose that's what I get for setting fields manually rather than using the solver). Immediately after programming the device, the output went to the programmed low error output (0.01V measured through the PTC-03). Attempting to read the EEPROM fails with a "The device is not recognized" message, however, the EEPROM Analyzer window shows data and a big red "Parity Failed" message.
Is there any way to bypass the parity check in order to reprogram the device with proper, valid contents? I had something similar happen a year ago on some -CC revision parts and, IIRC, there was a way to force the programmer to ignore the parity and reprogram the device.
programming the MLX90251
Question
I have samples of MLX90251 which I would like to test in our application. I wonder if the component works with factory defaults or if it is mandatory to "activate" the cell by programming the EEPROM inside. In this case where can I find the programming protocol.
Current Sensor
Answer
We do not have similar current sensor modules like the DHAB S/14.
What Melexis offers are sensors which can be used to measure current, but not the whole module.
For example the MLX90251, datasheet:
http://www.melexis.com/prodfiles/0004765_MLX90251_009.pdf
90251F problem with PTC-04
Question
I installed Melexis programmable toolbox, with PTC04UI and MLX90251UI.
I tried to program a 90251F device, but the program answer is: 'Firmware is not recognized as 90251'
We have read in a previous discussion that by default the software is configured for the '90251CC' and that in order to change the devices we should modify the .ini file. Is it still correct?
At second point, in the Application note of PTC04-DBHall (Apr 04) shows the connector layout in a wrong way. It seems to be pin-changed (1-8, 2-7 and so on).
Answer
For most MLX products there is a specific firmware, PSF and UI for the PTC-04 programmer. Therefore it is important to have the correct firmware loaded in the PTC-04 programmer.
At start-up the PSF layer checks the ID and revision of the firmware that is loaded in the PTC-04. If the firmware doesn’t support the MLX product of the PSF, the PSF layer returns an error message.
In such a case you have to upload the correct firmware:
Start the PTC04UI and press the upload firmware button ( or firmware commander) to upload the "ptc04_mlx90251_firmware.hex".
US1881
Answer
As you have surmised correctly this is not an appropriate use for this IC. The current in a PCB trace is generally much too small and generates a very weak magnetic field. Usually the field is orders of magnitude smaller than the field required to switch an 1881 Hall Latch. Even our linear Hall ICs, like the MLX90215 or MLX90251 are not sensitive enough for this task. Melexis has a device called the CSA1V that can be used to detect certain currents flowing in a PCB trace. You can learn more about this part at http://www.sentron.ch/csa.htm. Sentron is a Melexis company that specialies in advanced magnetic sensor technologies.
To make the US1881 work would require a toroidal ferrite core with the 1881 inserted into an air gap in the core and then likely several hundred turns of copper magnet wire on the core. The current would then be run through this coil and the field in the gap would be a multiple of the amp turns of the windings. I am sure this is not what you had in mind so look at the CSA1V and see if it could meet your expectations. This IC uses very clever on chip flux concentrator technology to give a more sensitive detection solution without requiring ferrite cores and windings.
MLX90251 and PTC-04
Question
I'm trying to program an MLX90251 with the PTC-04 board. I need to measure fields around 125mT (sensors type 2). In the programmer interface, i try to perform the liear set-up: position 1 is, for example, 100mT (0V) and position 2 is 150mT (5V). With a RG of 11 and a FG of 900 the system should work, but when I perform the linear set-up I always obtain the error: out of tolerance. Can you explain me how to program a sensor (in that range) without errors? Is there an example pdf in your website?
MLX90242LUA Hall Sensor
Answer
The 90242 does not have any user adjustable provision for temperature compensation of the magnetic material. The described temperature behavior indicates a Rare Earth Samarium Cobalt material is being applied. Is that correct? The Magnet is losing 3.5% of it field strength at the elevated temperature (128-25=103). This IC has a range for its' thermal coefficent of sensitivity and also for the drift of the null or Voq value. Both will influence the overall Vout drift due to the temperature change. But both have a statistical distribution within the typical range provided in the datasheet. It becomes quite limited to be able predict what any 1 IC will do without specifically characterizing that device over temperature and with a stable magnetic field (from an Helmholtz coil not a permanent magnet).
Meanwhile the MLX90215 or the MLX90251 are available as programmable Linear Hall IC's with the significant advantage that the temperature coefficient can be set to compensate for the loss in magnetic strength by increasing the gain of sensitivity an opposite amount.
PTC-04
Answer
Answer: for the installation procedure of the PTC04, please refer to the document: Installation_Guide_PTC04.pdf
This document can be found on the CD delivered with the PTC04 or at http://www.melexis.com
In a nutshell:
IMPORTANT: ALL INSTALLATIONS HAVE TO BE DONE WITH ADMINISTRATOR RIGHTS.
This means you need to have full access on your PC.
For the installation of the software, the PTC04 does NOT have to be connected to the PC. This is only necessary when you install the USB of the PTC04. If you want to use the USB of the PTC04, follow the procedure described in the chapter: Hardware: Question: How do I install the USB? You can install the USB before or after you install the software of the PTC04.
Installation from CD:
If you are installing the package from the CD, please follow the instructions
STEP 1: Start Autorun program from the CD.
STEP 2: Select the device you want to install. This will install the whole package. This means: if you select a MLX device, for example the MLX90251, all packages that are needed for the MLX90251 will be installed including the PTC04 modules. In this case it is not needed to select the PTC04 module afterwards.
STEP 3: Press Next > to install the module.
STEP 4: Select “I accept the agreement. And press
STEP 5: Next >
STEP 6: Press install.
STEP 7: Press Finish to complete the installation.
This procedure (step 3 – 6) is repeated for each module of the package automatically.
Installation from Package:
If you are not installing the package from the CD, please follow these instructions:
STEP 1: Put all software modules, except for the firmware, into one directory. The location of the directory on your PC is not important.
There are 6 software modules:
• 2 modules for the MLX product: (xxxxx = Melexis product number.)
o MLXxxxxx user interface (UI_0xxxxxAAMLX.exe)
o MLXxxxxx PSF (PSF0xxxxxAAMLX.exe)
For example:
MLX90251 user interface (UI_090251AAMLX.exe)
MLX90251 PSF (PSF090251AAMLX.exe)
• 2 modules for the PTC04:
o PTC04 user interface (UI_0PTC04AAMLX.exe)
o PTC04 PSF (PSF0PTC04AAMLX.exe)
• The MPT and the Melexis updater:
o MPT application (MPTApp.exe)
o Melexis Updater (MelexisUpdaterSetup.exe) - optional, the installation can be omitted. If this file is not in the directory, a warning is given and the installation is skipped.
STEP 2: Run the installation of the user interface (UI_0xxxxxAAMLX.exe).
For example: UI_090251AAMLX.exe.
This will install all other needed modules of the packages. The module is only installed if the previous installation has a lower revision number.
STEP 3: Press Next > to install the module.
STEP 4: Select “I accept the agreement. And press Next >
STEP 5: Press install.
STEP 6: Press Finish to complete the installation.
This procedure (step 3 – 6) is repeated for each module of the package automatically.
Answer
for instructions on how to upload the firmware of the PTC04, please refer to the document: PTC04_UI.pdf
This PTC04_UI.pdf document can be found on the CD delivered with the PTC04 or at:
http://www.melexis.com
In a nutshell:
The firmware loader is needed in order to upload new or other firmware into the PTC-04 programmer.
For most MLX products there is a specific firmware, PSF and UI for the PTC-04 programmer. Therefore it is important to have the correct firmware loaded in the PTC-04 programmer.
At start-up the PSF layer checks the ID and revision of the firmware that is loaded in the PTC-04. If the firmware doesn’t support the MLX product of the PSF, the PSF layer returns an error message.
In such a case you have to upload the correct firmware:
STEP 1: Start the User Interface of the PTC-04
STEP 2: Press the button Upload firmware
STEP 3: Select the firmware needed for your MLX product.
The firmware filename is called ptc04_mlx*****_firmware.hex or fir******aamlx.hex.
The marks ***** stand for the MLX product name.
For ex.: ptc04_mlx90251_firmware.hex or fir090264aamlx.hex.
Once the file is opened, the firmware is loaded in to the PTC-04 programmer. Afterwards the software verifies if the upload was done correctly.
Question
Error on RUN of PTC04 VB example Code
I have set up the code (in VB6) provided on page 8 of the "MLX90251 Product Specific Functions Software Library" programming guide. However when I try to run the program it errors on the following line: MsgBox (Dev.Name & " device found on " & Dev.Channel.Name) with the following message: "Object doesn't support this property or method" I have also adapted the code to VB.net and it errors at the same line: MsgBox(Dev.Name & " device found on " & Dev.Channel) but gives the following error message: "Attempted to read or write protected memory.”
Answer
Public Dev As MLX90251PSFDevice
The function should work, but you need to make sure that "Dev" is linked to the 90251PSF. “Dev” is not declared on page 8 of the PSF documentation, but it is mandatory: It should be a global variable:
Public Dev As MLX90251PSFDevice
MLX90251 PTC-03
Question
I need the MLX90251 software manual for the PTC-03 programmer. Is it still available on this site or how can I get it?
General quesions for MLX90251
Question
Do you provide SMD package in MLX90251?
Answer
Reply for both posted messages:
MLX90251 is available in so-called leaded package for thru-hole mounting (Single-in-Line Package - 4 leads - 4-SIP-VA).
Melexis offers the option of performing a trimming and forming of the leads in order to get a device suitable for SMD mounting. The parts are then delivered in pocket tape.
Melexis is currently qualifying the MLX90251 in TSSOP-14 package. Release expected by the end of the year 2005. Engineering samples are available in small quantity. It will be referred as MLX90251-E-GO (Option - 0, 1, 2 or 3) for the temperature range up to 85 Deg.C. and MLX90251-L-GO (Option - 0, 1, 2 or 3) for the temperature range up to 150 Deg.C.
This product is then similar to the MLX90277 but the MLX90251 has only one die while the MLX90277 includes 2 isolated dies in the same package (for redundancy purpose).
Both MLX90251 and MLX90277 can be programmed through the Standard Melexis Programming Unit PTC-04.
General quesions for MLX90215
Question
Can I use the MLX90215 or MLX90251 ,with a cylindrical magnet, to measure rotary angle and have a linear output with regard to the angle?
PTC04 VB interfacing
Question
I am trying to set up VB code to interface with the PTC04 programmer so that I can create a custom programming HMI in VB.
I have set up the code (in VB6) provided on page 8 of the "MLX90251 Product Specific Functions Software Library" programming guide. However when I try to run the program it errors on the following line:
MsgBox (Dev.Name & " device found on " & Dev.Channel.Name)
with the following message:
"Object doesn't support this property or method"
I have also adapted the code to VB.net and it errors at the same line:
MsgBox(Dev.Name & " device found on " & Dev.Channel)
but gives the following error message:
"Attempted to read or write protected memory. This is often an indication that other memory is corrupt."
Does anybody have any insight into this problem.
Answer
The function should work, but you need to make sure that "Dev"is linked to the 90251PSF.is not written on pag 8, but mandatory:
Public Dev As MLX90251PSFDevice
Buy MLX90251
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