FAQ:
Question 1: Who we are? Development / Production / Distribution?
Answer: The development and technical consultancy is located at Hoeben Electronics in the Netherlands. If you need technical consultancy then please contact Hoeben Electronics Email: info@hoeben.com, Our Hall Sensor production is located in Sweden at M A Kapslingsteknik AB. The worldwide distribution is located in Germany at CleverTrade Electronics GmbH. If you need info about pricing, delivery times or stock status, then please contact CleverTrade Electronics GmbH Email: info@CleverTrade.biz
Question 2: Which enclosures of the 1D Hall Sensors HE144 are available?
Answer: The HE144S (HE144 Standard), is ROHS compliant available in the identical enclosure version as the KSY14 and KSY44 from Infineon ex stock. End of may 2012 (see Sensor+Test 21th - 24th may in Nuremberg Booth 12-469) we will have the SMD BGA-LIKE version HE144SH = SMD horizontal with a size of 3*3*0.7 mm The HE144SH was designed for horizontal board mounting, the hall sensitive area is located at the top view. The HE144SH can also be used as ROHS compliant cross for the obsolete Infineon SMD type KSY44-E9300, but enclosure is different, so its only a electrical cross. The KSY14 is symmetric, this means input and output resistor is identical. The KSY44 is asymmetric, the input resistor is lower than the output resistor, according to the voltage at the output of the KSY44 is higher compared to the KSY14. Our cross part HE144 is as far as possible identical with the Infineon KSY44. The HE144 has also asymmetric input and output resistors, but he can be used for much stronger magnetic fields, up to 2.4 Tesla. The Infineon KSY44 ends at around 0,8 Tesla, usual analog hall sensor from our competitors end mostly at around 0.3 Tesla. Till end of year 2012 we will have the SMD version HE144SV which is electrical compatible to the HE144S. The HE144SV is designed for vertical board mounting, the hall sensitive area is located in the front point of view. The HE144SV can be used especially for current measurements. All three sensor contain internal the same DIEs and allow magnetic field measurements up to 2.4 tesla und frequency ranges up to 100 kHz.
Question 3: Which enclosures of the 1D Hall Sensors HE244 are available?
Answer: The HE244S (HE244 Standard), is a SMD SOLDER PAD version, which is also used as basic module for the HE244T (TWISTED PAIR Version = 20 cm) The twisted pair version HE244T can be used very variable, it can be easily adapted to different mechanical applications. Optional there is also a PIN version HE244P (MOQ=5K) available. But for this Pin version we have a minimum order quantity of 5000 pieces. End of may 2012 (see Sensor+Test 21th - 24th may in Nuremberg Booth 12-469) we will have the SMD BGA-LIKE version HE244SH = SMD horizontal with a size of 3*3*0.7 mm The HE244SH was designed for horizontal board mounting, the hall sensitive area is located at the top view. Till end of year 2012 we will have the SMD version HE244SV which is electrical compatible to the HE244S. The HE244SV is designed for vertical board mounting, the hall sensitive area is located in the front point of view. The HE244SV can be used especially for current measurements. All sensors of the HE244 family contain internal the same DIEs like the basic module HE244S and allow magnetic field measurements up to 5.0 tesla und frequency ranges up to 100 kHz. Daten: Magnetfeldmessung bis 5,0 Tesla, Frequenzgang bis 100 kHz, Linearitätsfehler: 0,1 – 0,2 x E-2, Temperatur Koeffizient: 0,15 x E-3 / Kelvin, Offset-Drift: 0,25 x E-6 Volt / Kelvin, offset-voltage at 1 mA: 10 x E-6 Volt.
Question 4: Which enclosures of the 3D Hall Sensors HE444 are available?
Answer: Our first product from this 3D Hall Sensor family is the HE444S as Solder/bond pad version (S=Standard). Optional the following variations can be ordered on request: Please take care this special enclosures have the following MOQ`s = minimum order quantities, so we order on customer request only. HE444T (MOQ=5) Twisted pair=20cm, on customer request. HE444F (MOQ=10) Flex Foil, on customer request, apply setup costs! HE444H (MOQ=20) extended temperature range, on customer request. HE444TH (MOQ=20) Twisted pair=20cm, extended temperature range, on customer request. HE444FH (MOQ=20) Flex Foil, extended temperature range, on customer request, apply setup costs! The HE444 comes with a PHE error (Planar Hall Effect Error) of 2xE-5 = 20 PPM = 0,002% only and can be used for strong magnetic fields up to 5 Tesla. Therefore we have 3 nearly 100% independent axes x, y and z. Measurements have been done by Cern Switzerland. Details to 3D Hall Sensor HE444 see application report, see webpage: www.CleverTrade.biz category HE444: 3D Hall Sensor Application HE444 CERN_ENG.PDF.
Question 5: What is the height of the sensitivity of the Hall Sensors?
Answer: HE144 family: Using a input current of 1 mA the sensitivity is 200 mV / Tesla.
Answer: HE244 family: Using a input current of 2 mA the sensitivity is 200 mV / Tesla.
Answer: HE444 family: Using a input current of 2 mA the sensitivity is 200 mV / Tesla.
Question 6: Is a calibration diagram available for each sensor?
Answer: No, the sensors itself are very accurate. If you realize a offset compensation, then the offset is eliminated, then you only need to calibrate the sensitivity, (the sensitivity is only a factor), then you reach for example in a measurement range of 0 - 1.5 Tesla a preciseness of < 0,1%. So we recommend the procedure described above for the HE144 family, because the offset is for example 10mV when you are using a current source of 1 mA. Using the HE244 family you do not take care for offset (offset is only around 100 microvolt). In most applications this minimized offset does not matter, so you need no compensation for the offset voltage. If you really need a calibration, then we recommend the company Projekt Elektronik in Berlin. Contact Mr. Heinze, Phone: +49 (0) 30 430322 41 Email: Heinze@projekt-elektronik.com Calibration of 100 pieces hall sensors costs around 60 - 80 EUR each at a temperature of 25 degrees = 298.15 Kelvin. If you really need a calibration for let us say very deep temperatures, then you have to find another solution, because standard calibration will be done at 25 degrees = 298.15 Kelvin. The sensitivity (gain) of hall sensors is depending from the temperature, and like you know standard calibration values apply to 25 degrees = 298.15 Kelvin.
Question 7: How are the characteristics of the Hall sensors at very low temperatures?
Answer: We tested up to now till - 196 degrees = 77,15 Kelvin in liquid nitrogen at University Delft in Netherlands. The input and output resistor was still at 500 Ohm (at 25 degrees = 298.15 Kelvin = 1000 Ohm). We actually do not know what happens at 4Kelvin = - 269 degree, but we believe that the sensor will work. These applications should be tested. We believe that the linearity will not be influenced. It is sure that the sensitivity (Gain), Offset, and resistor and also the noise will change. The noise will probably be even lower, also a reduced signal / noise relationship will probably happen. We believe that the mechanical stability should not be a problem. It is necessary for low temperature applications to run tests, we have actually some customers who test under low temperature conditions, the results will be published here when we have the results. For ambient temperature of 25 degrees = 298.15 Kelvin the HE244 has a sensitivity of 100 mV / Tesla using 1mA current source. Permanent operation of the sensor at low temperatures can be done using soldered sensors, using periodic operation like high to low, low to high temperatures may lead to weak solder pads. For such cases bonding is the better solution, this can be done using the HE244S type. Micro-welding is also possible, we use that partially. We can also produce the HE244T with Teflon / PTFE wires welded, this works good. Our actual HE244T has PU, this cannot be used for low temperature applications. The chip will not be destroyed using low temperatures. GaAs should work but has actually been tested only till - 196 degrees = 77,15 Kelvin. The resistor will be lower, that's sure, around 500 Ohm, at 25 degrees = 298.15 Kelvin the resistor has around 1000 Ohm. We actually do not know, what will happen with the other parameters, we have to wait for additional tests. The enclosure is a very good epoxy, this will not lead to trouble at low temperatures. UHV should not be a problem. The device has no cooling through air flow, only through IR and Pins / assembly. We do not know the optimized current for usage of the sensor at low temperatures, this should be tested. We recommend in first step to use 2 mA current source for test, or at low resistor (example 500 Ohms) you should select current in that way, so that the Voltage at Output of the sensor stays below 1 Volt (but not over 10 mA). The DIE base of all hall sensors is gallium arsenide, so this material can be used very good for low temperature applications.
Question 8: How to interpret measurement diagrams of HE244 (see http://www.clevertrade.biz/#HE244?
Answer: The measurement diagrams of HE244 show in page 2 for example the linearity error in relation to the magnetic field intensity. It does "not show " the output voltage related to the magnetic field intensity. The graphic diagram of the output voltage with a fault of 0.1% would be useless, it makes no sense to show this minimum linearity error, because it is not possible to see that graphically. See example: The green line in page 2, supposed: At 1 Tesla magnetic field the reference point the linearity fault is zero. The line y=ax+b (b is Offset) goes through reference point, and the difference variation will be shown graphically. a = Sensitivity (gain).
Question 9: What is the maximum frequency range. What is the maximum bandwidth, frequency response of the hall sensors?
Answer: See datasheet guaranteed are 0 - 100 kHz, probably you can use the sensors up to the lower MHZ region, we still had no measurement equipment up to now to test the MHZ range.
Question 10: Which relationship is between sensitivity, bandwidth and noise level?
Answer: All hall sensors (HE144, HE244, HE444 family) from Hoeben Electronics are analog based. If you compare with digital hall sensors or mixed technology hall sensors you will find nearly no signal delay time at analog hall sensors, that means this analog hall sensors have a significant bandwidth, guaranteed are 100 kHz, probably it is much more. The limits will be reported when we know it. At high frequencies (> 20 -50 kHz), grinding, capacities at sensor connections and the length of cable is playing a more and more important role. Already beginning at 20 kHz twisted pair wires should be used. General the usage of higher current sources, for example > 2 mA causes rising noise level. So we recommend for high frequency applications to use low current sources like < 1 mA for example. . Especially for motion control applications the noise relationship 1/f is important. Servo loops need a big bandwidth this means each signal delay in servo feedback loops lead to additional faults. In summary we recommend, the more you need bandwidth, the lower you should select the current for the hall sensor. (ASML and CERN use for example 0,25mA).
Question 11: Which influence has the noise level and a potential filtering to the frequency range?
Answer: Usage of filters to minimize noise will all time reduce the usable frequency range. We guarantee for all hall sensors a frequency range of minimum 100 kHz. One of our US customers compared our HE244 with a very good hall sensor from Bell Labs, the linearity was for both devices at 0,1 %, but the HE244 from Hoeben Electronics performed in relation to the noise level much better.
Question 12: How to realize a offset compensation?
Answer: See instruction "offset compensation" http://www.clevertrade.biz/#HE144 Compensation is only needed for HE144 family. The HE244 Sensor family has an offset of 100 microvolt only, so you need in nearly no cases any compensation.
Question 13: Are the sensors immune against radioactive radiation ?
Answer: The DLR = Deutsche Luft- und Raumfahrt = german aerospace made radio activity tests using HE144 family in last time. The Gama radiation showed good results, also the proton test. The results of ionic test (shooting to the open chips with H and AU ions) is actually in evaluation. We will report the results as soon as the tests are finished.
Question 14: When is a temperature compensation necessary?
Answer: Until now, we have not realized any integrated temperature compensation. As the hall sensors are very temperature stable, until now there was at no application necessary to implement a temperature compensation. The HE244/HE444 series has for example an temperature coefficient of 0,15 x E-3 / Kelvin, this makes an additional temperature compensation in almost all cases unnecessary. We use at the HE244/HE444 series DIEs pairwise, which are very similar to each other. Through the component-sided existing via hardware realized differential measurement, there are already many temperature influences eliminated.
Question 15: Is the integration of temperature compensation or amplifier reasonable, or rather possible?
Answer: Until now, we have still no integration of temperature compensation or amplifier realized. The technique exists, on customer demand we could gladly offer solutions.
Question 16: Which resolution respectively precision is possible with these hall sensors ?
Answer: The resolution depends on the electronic, the hall sensors are clear analoge components (you can no indicate much, like for example at a 12 Bit ADC a resolution of +/- 1 LSB), for this reason there are no Information in about this in the Datasheet. For the definition of the resolution you have to consider the course of the drift and the noise, see for this the link measurement-diagrams HE244 http://www.clevertrade.biz/#HE244
Question 17: How large is the measuring range of the magnetic field strength of the hall sensors?
Answer: The HE144 goes up to 2.4 Tesla, the HE244 goes as well as the 3D sensor HE444 up to 5 Tesla. These values will be guaranteed by datasheet. However we have customers, which have tested the sensors up to 13 Tesla, but we do not know actually the limits at very high field strenghts. Probably these errors will grow up at very high field strenghts, but this should not be a problem as long as you keep the inducted current low. Customers which for example have to measure up to 16 Tesla, we already have had this restrictions, should test this simply with supply currents of for example lower 0.5mA.
Question 18: Which activities can be done to avoid faults?
Answer: It is necessary to use a good amplifier (see for this the answer on question: recommended amplifiers) and the prevention of loops.
Question 19: Which information should be on hand at customer-specific hall sensor projects, to enable a optimal consultation?
Answer: How large is the magnetic field strength of your application? Which band width is necessary? Which demand on precision exists (resolution in micro tesla)? In which direction is the magnetic field drifting? Reasonable is a detailed project drawing, which shows the characteristics, respectively the direction of the magnetic field. For a calculation it is necessary to indicate the required quantities. For customer-specific new developments incurs NRE costs(none recurrent engineering costs).
Question 20: Which customer-specific applications are possible?
Answer: We are able for example at very close space ratio, to realize hall sensor arrays with several sensors in distance of only 1.8 mm. Especially qualified are our sensors for very high field strengths (up to 5 Tesla) at very high frequencies (up to 100 kHz and more) and resolutions of up to micro Tesla.
Question 21: Where is the hall sensitive area located at the hall sensors?
Answer: HE144 series: The sensitive area is arranged in the centre of the chip. See for this datasheet, the Z-direction (this means the magnetic field vector enters the marking) The active area is about 280 micrometer below the marking. Answer: HE244 series: The sensitive area is arranged nearly in the same x, y direction like at the HE144, see for this datasheet HE244. In Z-direction the sensor measures an average value of a depth of about 430 micrometer in the Z-centre of the component. Both DIEs of HE244 are inserted extremely plain, this results in as very correct Z-orientation. Answer:: HE444 series: The magnetic centre of all 3 axes is arranged in the centre of the component. Every axis crosses the other axis on the same point (Requirement: Supposition of a homogeneous magnetic field!) The dimensions outside are 3.3 x 3.3 x 3.3 mm. For further information see datasheet HE444.
Question 22: Which meaning has the PHE-error (Planar Hall Effect Error) at 3D hall sensors?
Answer: A 3D hall sensor should always give only one answer in Z-direction. The PHE (Planar Hall Effect) however gives also an answer to fields in X- and Y-direction. More worse is, that the most 3D hall sensors forwards the errors as multiplication in X- and Y-direction. Inn a homogeneous magnetic filed the measuring point is always exactly in the centre, no matter if there are used 3 or 6 axes in a 3D hall sensor. You can always measure the dimension and the direction of a magnetic field. In a non-homogeneous magnetic field however, you will receive an adjustment of the centre. Through the usage of 6 sensors (average value measurement) the measured field does not correspond do the real existing field in the centre of the sensor. The residual errors, which are still exists, are very low and insignificant. Hall sensors with a PHE error of 1% can be corrected only very difficult and extensive, rather not anymore. This mistakes are at nearly all 3D hall sensors our competitors at around 1%. We are in the range of 20 ppm, at around the factor 500 better. These measured values are coming from Cern, from electron synchrotron Switzerland. In summary we can say: At 3D hall sensor measurements at inhomogeneous magnetic fields the HE444 is supposable the worldwide the best qualified hall sensor on the market. Detailed information for 3D Hall Sensor HE444 application report, see website "www.CleverTrade.biz" category HE444: 3D Hall sensor application HE444 CERN_DE.PDF
Question 23: What are the advantages and disadvantages of the HE144 compared with HE244?
Answer: Advantages of the HE144: The HE144 is cheaper as the HE244 and has a higher sensitivity, so you need less amplification with man the same measuring current. Please notice: The sensitivity is not very important. More important is the relation of the signal/noise. You can for example induct the double amount of current at the HE244, wiht it you have the same signal again. Answer: Disadvantages of the HE144: The offset of the HE144 (zero-point voltage) is approximately 10 mV at 1 mA measuring current. If you need a high amplification, you have to compensate the offset, see for this our application note "Offset Compensation.pdf". Without compensation you will also amplify the offset and then the amplifier turns to saturation. Drift: Although the drift is very low, lower as it would be expected, there is still the temperature drift of the offset existing. For applications, which do not need any absolute value, this is not important. When switching-on, all will be heated, then the signal is not as stable as at the HE244 (although it is already much stable than at the most other industry-standard hall sensors), ASML in the Netherlands uses the HE144 sensor for example as this sensor has a very low noise compared to competitor products. Answer: Advantages of the HE244: The HE244 has a much more low offset voltage (liegt im Bereich von 100 micro Volt, (at around 100 microvolt, that means around 500 times better then the HE144)). Thereby It is much easier to amplify without doing an offset compensation at the instrument amplifier. So you save on the efforts for electronic and calibration, the development and construction will be easier. Very low drift of the offset: The sensors have nearly no temperature drift. This makes the measuring much more easy, as the sensors thereby have also a lower 1/f noise and a very stable. Also a long term drift is almost not existing. The HE144 is relating to the long term drift already good, but the HE244 is classes better, as the very low 1/f noise enables a very stable signal. Small changes in the magnetic field are to be regarded without any filter procedures, you can measure very high frequency responses, up to at least 100 kHz. Answer: Disadvantages of the HE244: The HE244 is compared with the HE144 considerably more expensive.
Question 24: Which supply currents do our customers use?
Answer: Nearly all customers are using a constant current source as supply! Many customers are working with 1 mA, others with 0.18 mA or 0.25 mA. Generally it is imperative, the lower you choose the supply current, the lower is the heat development and with it also the noise. Due to the principle at hall sensors is exclusively recommended the usage of a constant current source. Voltage supply sources are not suitable!
Question 25: Which amplifier do we recommend for your electronic?
Answer: For lowest noise and good precision, the LT1678 from Linear Technology is a very good choice. If you need a low power application and a good noise performance, we recommend the LTC6078 from Linear Technology, as instrument amplifier the LT1789 would be a good choice.
Question 26: Can you give a recommendation regarding electronic components for our design?
Answer: We recommend the following components from Linear Technology, which have already been tested from us with our hall sensors: LTC6084, LTC6081, LTC6087, LTC1128 and LTC1028. As instrument amplifier the LTC1167 is cheap but very exact! For test purposes we recommend the a litte bit more expensive, but even better instrument amplifier LT2100. For A/D applications we recommend the ADCs LTC6655, LTC2379 and LTC2442.
Question 27: Is there a SDK-Kit existing for such as a labview connection of the hall sensors with integrated current source?
Answer: Unfortunately until now it is no SDK-Kit existing. Preferable would be a SDK-Kit with USB interface to labview (National Instruments) with an integrated prgrammable current source of 0-10 mA. With 18 Bit ADC resolution, a sensor resolution of 2 microvolt would be reachable. The HE244T has a sensitivity of 200 mV / Tesla at 2mA supply current and the HE144 has a sensitivity of 200 mV / Tesla at 1mA supply current. Unfortunately there is actually no suitable kit existing on the market, neither from National Instruments, nor from Keithley or Agilent.
Question 28: You have some more questions ? You miss some answers in our FAQ list, then please let us know!
Answer: Send us your questions, we will do our best to answer ASAP!