Q: ADIS16209 Datecode Revision Change

Q What is the meaning of this &bdquo;R“ in the Datecode 1224R of the ADIS16209. A The “R” indicates that these units have had the firmware upgrade, so they would behave the same way as units with later date codes.

Question 1

Tilt Angle Window Detector

Accepted Answer

Q: 
 How can I use a tilt sensor to determine if my instrument has move clockwise or counterclockwise? 
 ----------------------------------------------------------------------------------------------------------------------------------------------- 
 A: 
 The ADIS16209 offers a an accurate tilt sensor function, along with two programmable alarms that will simplify this process. The ADIS16209 offers both horizontal (XINCL_OUT, YINCL_OUT) and vertical (ROT_OUT) tilt angle measurements, using a fully-calibrated dual-axis accelerometer. If we assume that the axis of rotation is perpendicular to gravity and to one of the accelerometers, one might be able to accomplish this using one of the horizontal outputs and the two alarms. For this discussion, let's assume that the reference position is when the x-axis is at 0 degrees, clockwise rotation produces a positive response and counterclockwise rotation produces a negative response. 
 ALM_CTRL = 0x661F 
 ALM_MAG1 = 0x8028 
 ALM_MAG2 =0x3FD8 
 The ALM_CTRL setting options are located on page 16 of the ADIS16209 (Rev C) datasheet . Setting this to 0x661F establishes the following settings: 
 
 Set Alarm 1 and Alarm 2 to monitor XINCL_OUT 
 Use static level comparisons (not dynamic, "rate of change") 
 Use filtered data for both Alarm 1 and Alarm 2 
 Set DIO2 as a positive-polarity alarm indicator. 
 
 Setting ALM_MAG1 = 0x8028 establishes the Alarm 1 threshold at greater than 1 degree. 
 Setting ALM_MAG2 = 0x3FD8 establishes the Alarm 2 threshold at less than -1 degree. 
 So, DIO2 will go high when XINCL_OUT is greater than 1 degree or less than -1 degree. 
 In order to discriminate between Alarm 1 (clockwise) and Alarm 2 (counterclockwise), monitor STATUS[9:8], using the SPI port. For more information on the STATUS register, refer to page 18 in the ADIS16209 (Rev C) datasheet . 
 Note that this technique will also work when using the ADIS16201 , ADIS16203 or ADIS16210 . 
 For a step-by-step guide for testing this, using the ADIS16209/PCB and EVAL-ADIS, click on the following link: 
 https://ez.analog.com/docs/DOC-10180 
 I hope that helps! 
 Best, 
 NevadaMark

Question 2

ADIS16209/ADIS16265 Lead Integrity

Accepted Answer

UPDATE ALERT! 
 Please visit the following link for an updated set of assembly instructions: 
 FAQ: ADIS162xx LGA Assembly Guidelines 
 
 Start of older assembly instructions, for historical reference but not for present use>> 
 Q: 
 What is causing my ADIS16209 leads to fracture or crack on my PCB? 
 A: 
 -------------------------------------------------------------------------------------------------------- 
 Without knowing specific details of any particular case, we can offer that this is most often caused by PCB bending, which places peeling stress on one or more of the leads. From our experience, the two most common causes of PCB bending are in the array separation process (after array-level processing is complete) and in drop testing (in-system). While the bending stress associated with score and snap operations may seem to be very small, the ADIS16209's rigid structure (for best physical stability while in normal operation) and small leads do not provide a large amount of adhesion strength either. Keep in mind, this is not a matter of device quality, but a matter of physics. 
 Fortunately, there are two things that can be done to help address this sensitivity. 
 
 Employ a low-stress array separation technique. For example, we use a router bit to cut finished PCB out of their arrays for our evaluation boards, such as the ADIS16209/PCBZ . This process has helped produce over 3000 boards with very high yields. 
 Use an under-fill material to spread peeling stress across the entire ADIS16209 package bottom. 
 
 SUGGESTIONS FOR ADDITIONAL READING: 
 Use of under-fill materials, for the purpose of strengthening BGA and LGA interfaces: 
 http://www.embedded.com/design/system-integration/4235387/Underfill-revisited--How-a-decades-old-technique-enables-smaller--more-durable-PCBs 
 The impact array separation techniques have on ceramic capacitors: 
 http://www.smtinline.com/html-en/cap-failure.html 
 For more detailed information on ADIS16xxx LGA assembly, check out the following post: 
 https://ez.analog.com/docs/DOC-2962 
 Hope that helps everyone! 
 Best, 
 NevadaMark

Question 3

ADIS16209 Evaluation Tool Overview

Accepted Answer

Q: 
 Where do I find information on evaluation tools for the ADIS16209 Tilt Sensor? 
 ---------------------------------------------------------------------------------------------------------------- 
 A: 
 We offer two different tools that support early evaluation of the ADIS16209. 
 First, the ADIS16209/PCBZ is breakout board which simplifies the process of connecting the ADIS16209 to an existing embedded processor system. For more information, please visit its product page at: 
 ADIS16209/PCBZ | Analog Devices 
 Also, check out page 20 of the ADIS16228 datasheet (Rev E) to access documentation for the ADIS16209/PCBZ 
 http://www.analog.com/media/en/technical-documentation/data-sheets/ADIS16209.pdf #Page=20 
 
 Note, in future revisions, this information may be on different pages of the datasheet 
 
 Second, the EVAL-ADIS provides a simple method for PC-based communication and data collection from the ADIS16209. For more information on this tool, please visit its product page at www.analog.com/EVAL-ADIS and the following Wiki Guide link for setup and use guidelines: 
 ADIS16209 EVALUATION ON THE EVAL-ADIS [Analog Devices Wiki] 
 These evaluation boards are available for order online at the following link or through our sales channel. 
 http://www.analog.com/en/products/mems/isensor-mems-accelerometer-subsystems/adis16209.html#product-samplebuy 
 For a list of authorized distributors by region, please click on the following link: 
 Sales and Distribution | Analog Devices

Question 4

ADIS16209 Self-Test Management

Accepted Answer

Q: 
 When my ADIS16209 starts up, STATUS = 0x0020, which indicates a self-test failure, but the rest of the operation seems to be fine. Is this real? What should I do? 
 ---------------------------------------------------------------------------------------------------------------------------------- 
 A: 
 At the time of this post, the ADIS16209 datasheet (Rev C) contains some errors in this description, which are being addressed in an upcoming revision. In advance of this, update let's use this discussion to describe the self-test function correctly, for those who are having similar experiences. The self-test function applies an electrostatic force to the MEMS structure, inside of the core sensor, which causes the structure to move in a manner that simulates its response to gravity or linear acceleration. This provides an observable response in the accelerometer outputs, that can serve as a validation of &ldquo;functional operation&rdquo; throughout the entire signal chain. The MSC_CTRL register provides two different options for using this function: manual (user-command) and automatic (during start-up/reset recovery). 
 The manual self-test control is an on/off control for the electrostatic force. Set MSC_CTRL[8] = 1 to turn it on and set MSC_CTRL[8] = 0 to turn it off. For normal operation, this will be in the "off" state but this control bit provides an opportunity to activate it at anytime, so that system processors can apply application-relevant pass/fail criteria to the responses. When MSC_CTRL[10] = 1, the automatic self-test process runs the ADIS16209 through on/off states, while observing the difference in accelerometer response, between "self-test on"and "self-test off." This process concludes with a comparison of the differential response in each accelerometer, with internal pass/fail limits and a report of the result to STATUS[5]. Once the ADIS16209 completes is its start-up process, STATUS is available for a SPI-driven read, using DIN = 0x3C00 as the SPI input command (STATUS at address 0x3C). Linear motion during the start-up process, VDD ramp rates/waveform and the tilt of the device can introduce uncertainty into the on/off levels and in some cases, cause a "false failure" report to STATUS[5] (0x0020). While the selection of the pass/fail limits incorporates most conditions, we have seen a few cases of false failures and the recent updates for improving ADIS16209 sensitivity to power supply configuration seem to have increased this sensitivity a small amount. 
 When presented with a self-test failure indication, where STATUS > 0x0020, use the following process to manually check for basic function in the ADIS16209: 
 
 Starting assumptions:
 
 No linear motion 
 Stable VDD

Set AVG_CNT = 0x0000 and SMPL_PRD = 0x0008, in order to optimize the response times during the self-test transitions, while keeping the ADIS16209 in low power mode. In this configuration, the self-test response will be similar to a step response of a single-pole, low-pass filter that has a cutoff frequency of 50Hz. 
 Read XACCL_OUT and YACCL_OUT 
 Set MSC_CTRL[8] = 1 
 Delay > 20ms, which provides the 50Hz filter (internal to ADIS16209 ) with at least ~ 6 time constants to settle. 
 Read XACCL_OUT and YACCL_OUT 
 Calculate difference in measurements:
 
 D-XACCL_OUT = XACCL_OUT (step 6) - XACCL_OUT (step 3) 
 D-YACCL_OUT = YACCL_OUT (step 6) - YACCL_OUT (step 3)

Set MSC_CTRL[8] = 0 
 Restore SMPL_PRD and AVG_CNT registers to their operational values 
 Determine "normal operation" by make sure that the D-XACCL_OUT and D-YACCL_OUT produced a change of at least 350LSB. NOTE: 350 LSB is approximately one-half of the datasheet specification for the "minimum" response time but is well above the noise floor. Since this test is designed to find major issues, like "no response," this should be a safe approach for pass/fail criteria. 
 
 Let me know how this works and please feel free to post any questions you have. 
 Best regards, 
 NevadaMark

Question 5

ADIS16209/ADIS16265 Pb-free Assembly Tips

Accepted Answer

UPDATE ALERT! 
 Please visit the following link for an updated set of assembly instructions: 
 FAQ: ADIS162xx LGA Assembly Guidelines 
 
 Start of older assembly instructions, for historical reference but not for present use>> 
 Q: 
 Do you have any tips to offer for PB-free, solder-reflow assembly on LGA iSensor devices, such as the ADIS16209 or ADIS16265 ? 
 ----------------------------------------------------------------------------------------------------------------------------------------------------- 
 A: 
 The iSensor devices, which come in LGA package styles, support standard Pb-free, solder-reflow assembly techniques. When designing an assembly process flow, please keep the following things in mind, which seem to be the most common themes associated with low-yields through PCB-level assembly operations. 
 
 Moisture ingression prior to solder reflow .. While some of the ADIS16xxx devices fall under MSL3, all of the ADIS1620x and ADIS1626x devices are classified as MSL5, per JEDEC J-STD-033. These devices are stored and shipped in compliant (per JEDEC) trays, which are vacuum-sealed with moisture absorbing materials, inside of an anti-static bag. J-STD-033 describes the floor life (time between bag opening and solder reflow), environment (temperature, humidity) and pre-reflow bake requirements. If these parameters are not well-controlled, baking these devices for 24-48 hours at +125 &deg; C, inside of a dry oven (nitrogen), will help remove any residual moisture and reduce its impact on assembly yields. J-STD-033 is available for download at http://www.jedec.org/standards-documents . 
 Solder-reflow time/temperature profile . These devices have been qualified to support the Pb-free solder reflow profile in J-STD-020. Prior to running parts through an oven, use an accurate thermocouple, placed at the DUT on the PCB, to verify compliance with the reflow profile in J-STD-020. J-STD-020 is available for download at: http://www.jedec.org/standards-documents .
 
 NOTE: The maximum temperature has a height condition in these specifications. For the ADIS1620x and ADIS1626x products, this places the maximum temperature at +250C, not +260C.

Peeling stress can cause device leads to fracture. This is a common sensitivity for LGA and BGA packages. A common cause of peeling stress is PCB separation techniques, which causes the PCB to bend and places the lead interfaces in "tension." Cracks in these lead interfaces can cause poor yield and premature failures in service, so this is an important consideration. There are two parts to managing this risk: optimize lead strength and protect the leads from peeling stress. Here are tips in optimizing the solder joint quality:
 
 Uniform solder deposition on PCB: 0.005" stainless steel stencil, with trapezoidal cuts (for easier solder release, reduce smearing) 
 Pad size: See "symbols and footprints" section on product pages for CAD library parts. For example, click on the following link for ADIS16209 CAD part: http://www.analog.com/en/mems-sensors/mems-inertial-sensors/adis16209/products/symbols-footprints.html 
 Optimal solder reflow profile.

Protecting the leads can involve the following:

ADIS16xxx boards (such as ADIS16209/PCBZ) use a rotating bit to cut boards out of the arrays, after the solder reflow step. 
 PCB design: break-point size, break point proximity to ADIS16xxx device, mounting hole location, thickness, width, length and material rigidity; along with device proximity to natural bend points, can impact exposure to peeling stress. 
 Clamp PCB ends during separation 
 Use of an underfill compound to help distribute peeling stress across the entire bottom of the package. The following materials, provided by Hysol, have been used with success: FP4470, FP4545FC, FC4502, and FP4548. The following tips may help in developing an under-fill process:

Pre-heat the PCB to +90 &deg; C, to help the material whick under the ADIS16265 's package bottom. 
 Deposit under-fill material on two adjacent edges of the ADIS16265 and allow the material to wick under the package, for approximately 30 minutes 
 Bake at +125 &deg; C for 30 minutes to help the material set 
 Bake at +160 &deg; C for 90 minutes to fully cure the material

This information applies to all iSensor BGA and LGA devices: ADIS16003 , ADIS16006 , ADIS16060 , ADIS16201 , ADIS16203 , ADIS16204 , ADIS16209 , ADIS16220 , ADIS16240 , ADIS16260 , ADIS16265 and ADIS16266 .

Question 6

ADIS1620x/21x/22x Power Regulator Suggestion

Accepted Answer

Q: 
 What linear regulator would you suggest for use with the ADIS1620x/21x/22x products? 
 ------------------------------------------------------------------------------------------------------------------------------ 
 A: 
 The ADP1712 appears to offer the best start-up waveform characteristics for products like this. We are presently working on a reference design, but thought we would offer the schematic for those who are presently considering this. As we work our way through the validation process, we will post new details in future discussions. 
 Hope that this helps!

Question 7

ADIS1620x/21x/22x Power Supply Considersations

Accepted Answer

Q: 
 Do the ADIS1620x/21x/22x products have any unique power supply requirements? 
 A : 
 ---------------------------------------------------------------------------------------------------------------------- 
 The ADIS1620x devices are complete digital sensor systems that provide calibrated tilt sensor outputs. The include a MEMS accelerometer, an analog front end and an embedded processor to support incline angle computation, application of correction formulas, filtering and the user interface. While these products don't present any unique requirements, which would not be risk items for other embedded processor systems, it may be helpful to refresh on some basic "best practices," through the use of reference design. Through all of our work in supporting our customers, we have found that the following attributes need consideration when developing a supply for these devices: 
 
 Avoid passive elements that are in between controlled voltages and the VDD/GND pins on the ADIS1620x. They tend to elevate the dynamic source impedance, which creates more local noise that can cause problems. 
 Leverage a regulator that provides a linear ramp for VDD, which moves its voltage from 0 to 3V in 100us or less. The ADP1712 is one example of a linear regulator that will support this. 
 Manage ramp rates to avoid tripping over-current protection systems. The ADIS162xx devices all have > 2uFof capacitance across the VDD/GND pins. 
 While the fast ramp rate will help manage this risk, be sensitive to noise sources. While there is not pass/fail criteria, one could use +/-10mV as a starting point for investigating potential problem spots.

Question 8

ADIS162xx LGA Assembly Guidelines

Accepted Answer

Q: 
 In addition to the standard JEDEC guidelines, J-STD-020 (solder reflow) and J-STD-033 (moisture sensitivity), do the ADIS162xx LGA devices have any other requirements for installation on to my PCB? 
 ----------------------------------------------------------------------------------------------------------------------------------------------------- 
 A: 
 J-STD-020 and J-STD-033 apply to single-die packaging, which leverage materials that support support exposure to temperatures of up to +260C. The ADIS162xx device are system-in-package (SIP) solutions, which include a wider set of components and assembly materials. 
 Some of these materials present elevated yield risk when the temperatures exceed +240C and or when the devices experience moisture ingression prior to solder re-flow assembly. 
 Moisture ingression prior to solder reflow . All of the ADIS162xx LGA devices have passed qualification testing for the MSL5 rating, per JEDEC J-STD-033. In serving a broad, diverse market, we have found that while ADI testing and characterization of MSL5 has proven successful, the ADIS162xx LGA package style can have a little more sensitivity to process variation, with respect to moisture ingression risk, when compared to typical companion devices. Therefore, ADI recommends the following process step for the ADIS162xx devices: 
 
 24 hour/+125C dry-bake exposure, prior to PB-free solder reflow processing. 
 J-STD-033 is available for download at http://www.jedec.org/standards-documents .

Solder-reflow time/temperature profile . The ADIS162xx package style and size fall under the +250C peak temperature requirement, per JEDEC J-STD-020C. Due to the sensitivity of some materials used inside of the ADIS162xx LGA devices, ADI recommends that the peak temperature, at the site of the ADIS162xx LGA device, not exceed +240C during solder reflow. All other temperature reflow guidelines, per JEDEC J-STD-020. 
 
 J-STD-020 is available for download at: http://www.jedec.org/standards-documents .

Peeling stress can cause device leads to fracture. This is a common sensitivity for LGA and BGA packages, but the ADIS162xx LGA devices have a bit more sensitivity to this than typical companion devices. The reason for this sensitivity is due to the rigid packaging materials, which support best sensor performance metrics when experiencing changing stress profiles from the PCB. A common cause of peeling stress is PCB separation techniques, which causes the PCB to bend and places the lead interfaces in "tension." Cracks in these lead interfaces can cause poor yield and premature failures in service, so this is an important consideration. There are two parts to managing this risk: optimize lead strength and protect the leads from peeling stress. Here are tips in optimizing the solder joint quality:

Uniform solder deposition on PCB: 0.005" stainless steel stencil, with trapezoidal cuts (for easier solder release, reduce smearing) 
 Pad size: See "symbols and footprints" section on product pages for CAD library parts. For example, click on the following link for ADIS16209 CAD part: http://www.analog.com/en/mems-sensors/mems-inertial-sensors/adis16209/products/symbols-footprints.html 
 Optimal solder reflow profile.

Protecting the leads can involve the following:

ADIS16xxx boards (such as ADIS16209/PCBZ) use a rotating bit to cut boards out of the arrays, after the solder reflow step. 
 PCB design: break-point size, break point proximity to ADIS16xxx device, mounting hole location, thickness, width, length and material rigidity; along with device proximity to natural bend points, can impact exposure to peeling stress. 
 Clamp PCB ends during separation 
 Use of an underfill compound to help distribute peeling stress across the entire bottom of the package. The following materials, provided by Hysol, have been used with success: FP4470, FP4545FC, FC4502, and FP4548. The following tips may help in developing an under-fill process:

Pre-heat the PCB to +90 &deg; C, to help the material whick under the ADIS16265 's package bottom. 
 Deposit under-fill material on two adjacent edges of the ADIS16265 and allow the material to wick under the package, for approximately 30 minutes 
 Bake at +125 &deg; C for 30 minutes to help the material set 
 Bake at +160 &deg; C for 90 minutes to fully cure the material

Question 9

Tilt Angle Window Detector with Evaluation Tools

Accepted Answer

Q: 
 Is there a way to test settings in the " Tilt Angle Window Detector " post with the ADIS16209/PCBZ and EVAL-ADIS ? 
 ---------------------------------------------------------------------------------------------------------------------------------------------------- 
 A: 
 Yes, start with the the ADIS16209/EVAL-ADIS Wiki Guide , for basic setup instructions. The following 16 figures illustrate a step-by-step process for implementing and testing the " Tilt Angle Window Detector. " Click on each graphic for better resolution review. 
 STEP #1 - Click on the Read button to verify normal operation. Click on Stop after validating function. 
 
 STEP #2 - Click on the Register Access button. 
 
 STEP #3 - Click on the Write button, which is associated with the Auto Null. 
 NOTE: This is the same as setting COMMAND[0] = 1 
 NOTE: Best results come from default settings and ~1.5 seconds of zero motion, prior to execution. 
 
 STEP #4 - Exit from the Register Access menu and click on Read , then click on Stop , to verify that the XINCL_OUT and YINCL_OUT numbers are close to zero. 
 
 STEP #5 - Click on the Register Access menu and then select the ALM_MAG1 register with a left-click on the mouse. 
 
 STEP #6 - Click on the New Hex Value box and type 8028 inside of this box. 
 
 STEP #7 - Click on the Write Register box to write to this register 
 
 STEP #8 -Select the ALM_MAG2 register with a left-click on the mouse. 
 
 STEP #9 - Click on the New Hex Value box and type 3FD8 inside of this box. 
 
 STEP #10 - Click on the Write Register box to write to this register 
 
 STEP #11 -Select the ALM_CTRL register with a left-click on the mouse. 
 
 STEP #12 - Click on the New Hex Value box and type 661F inside of this box. 
 
 STEP #13 - Click on the Write Register box to write to this register 
 
 STEP #14 - Click on the Write button next to the Flash Update command. 
 
 STEP #15 - Notice that the STATUS ( DIAG_STAT ) register is equal to 0x0000 when the orientation has not changed. 
 
 STEP #16 - Tilt the ADIS16209 in the direction shown below, then click on Update Registers in Category , to observe the change in the STATUS ( DIAG_STAT ) register. 
 
 STEP #17 - Set the ADIS16209 back to its starting orientation and click on the Write button next to the Clear Status Flags command. Notice how the error flag returns to zero in the STATUS ( DIAG_STAT ) register. 
 
 STEP #18 - Tilt the ADIS16209 in the direction shown below, then click on Update Registers in Category , to observe the change in the STATUS ( DIAG_STAT ) register.

Question 10

IMU Evaluation Software Bug: ADIS16209 Data Capture

Accepted Answer

TITLE 
 IMU Evaluation Software Bug: ADIS16209 Data Capture

VERSION 
 v1.17.3

SYSTEMS 
 EVAL-ADIS, EVAL-ADIS2

DESCRIPTION 
 
 The Data Capture menu is not configuring the ADIS16209's data ready on the correct DIOx line, according to the ADIS16209's Wiki Guide: 
 ADIS16209 EVALUATION ON THE EVAL-ADIS [Analog Devices Wiki]

SOLUTION 
 
 Use the most recent version of the program (v1.17.5, at the time of this post), which will be online at the following two sites, by 1/5/2017 
 
 EVAL-ADIS Web Page (Software Section) 
 EVAL-ADIS2 Web Page (Software Section) 
 
 NOTE: Also see file attachment, for those who need immediate access. After 1/5/2017, please visit the above sites for the most recent software version.

12/27/2017 UPDATE: File attachment removed. Please visit evaluation tool pages, to access the latest software version.

Question 11

The direction of axis X and axis Y

Accepted Answer

Q 
 Below is the fig 18 in datasheet, I think, for the fig in the middle, it should be X out = 0, and Y out has a certain output; and the right fig has the same problem. It seems not correct of the direction of axis X and axis Y , or the notes of middle and right fig is wrong. 
 
 A 
 If you look at the notations on the Left-Figure (indicating what produces a positive x-axis and y-axis response), then the middle and right figures appear to be correct. Though, personally I agree that the notations/conventions are a little confusing.

Question 12

Bias Stability over 1 Year

Accepted Answer

Q 
 Do you have any aging data related to the one year bias stability? 
 
 A 
 The key limitation is in the ARW (Acceleration Random Walk). For the accelerometer in the ADIS16209, the ARW is ~30ug/sqrt(hour). If we look at this over a one year period, we can calculate it in the following manner: Error = 0.00003 x sqrt(365x24) = 2.8mg Angle-error = asin(0.0028) = 0.16 deg

Question 13

ADIS1620x Evaluation Board dimensions

Accepted Answer

Q 
 We designed a PCB and we want to mount ADIS16209 Evaluation Board on this PCB. Therefore the dimension of the board are important. This information is missing from the mechanical drawing in the ADIS1620x_PCB datasheet? 
 
 A 
 We don't have any better drawing for PCB dimensions. I have measured the overall board dimensions 31mm x 33mm. The four mounting holes on the PCB are suitable for 2mm screws (M2). I have added this information to the datasheet drawing and attached it to this FAQ. In future revisions of the datasheet we will add this information to the datasheet drawing. 
 
 Attachments: 
 
 ADIS1620x_PCBwithdimensions.pdf

Question 14

ADIS16209: Stability and sensitivity

Accepted Answer

Q 
 For my application, timing is nearly no problem. I would rotate the sensor slowly (3 rev/min) around the axis which inclination should be determined. The measured acceleration shows a sine-dependency with rotation angle, where the amplitude is proportional to the tilt angle of the rotation axis. Thus the total measurement is insensitive to the sensor's offset. I am now concerned about the temperature stability and temperature hyteresis of the sensitivity. The operating temperature range is planned to be 5-45&deg;. We could do a precise factory calibration of the sensitivity at 25&deg;C to compensate for sensor to sensor-variations. Thus we would also limit the temperature deviation from this reference measurement to +/-20&deg;C. We can allow the in-field deviation of the sensitivity with respect to our in-factory calibration of 0.01&deg;/5&deg; = 0.2%. The values from the datasheets of both sensors are are larger but also given for larger operating temperature ranges. From fig.12 of the datasheet for ADXL213, it would seem as if the example curves for this sensor would meet my requirements. Do you know how the sensitivity behaves in this limited temperature range for both models, also concerning hysteresis, and if they will fulfil my requirements? For sensor ADXL213, the temperature effect on the sensitivity accounts for 0.3%. The sensitivity is specified from 27 to 33%/g. What effects account for the remaining deviation? Is the remaining deviation fixed (with time and other parameters) and can be compensated using one individual measurement? An accuracy of 0.01&deg; corresponds to 1.7e-4 g. To achieve this, the noise should be below this value. Can I expect for the digital outputs of both sensors, that the noise after averaging over timt t follows a 1/sqrt(t) behaviour? In that case, both sensors would meet my requirements after slightly more than 1 second of averaging. The digital resolution of the ADIS16209 is 0.244 mg = 0.014&deg; and thus above my accuracy goal. I expect, that with averaging I will nevertheless achieve this goal. On page 8 of the datasheet for ADXL213 you state: "As a result, there is essentially no quantization error or nonmonotonic behavior". Can you quantify "essentially no" or tell me at least that it is better than what I need? The measurement would be sensitive to drifts of the offset value while measuring. Can you specify or at least comment on the stability of the offset on this long time scale, assuming the temperature would be constant? 
 
 A 
 I sent four questions to another engineer, who has a little more insight into the ADXL213 operation than I do, and here is the summary of the responses: Q: Have you seen any customer accomplish 0.01 degrees of accuracy using the ADXL213? A: No. That doesn't mean it's not been done though. Still, 170&micro;G accuracy seems impractical to me (resolution, maybe - but not accuracy). Q: Thermal hysteresis over 5-45 degC. A: I have no data for such a small temperature range, but my guess would be 0.5mg. (over a temperature range of 160&deg;C I have occasionally seen as much as 8mg, so over a temperature range that is one quarter as large I would guess that it would be ~one sixteenth). Q: Noise: In a previous discussion, I believe that you offered that the 1/f frequency was approximately 0.25Hz. Would I be correct in that 160ug x sqrt(1.57*0.25) = 100ug is the lowest noise we could expect? A: Seems reasonable. Q: Pulse-width timing: I have never used an accelerometer in this fashion. Does this become a performance limit, or has this factor already been incorporated into the sensitivity graphs? A: If the PWM period is set to 10ms (100Hz) with a scale factor of 30%/g, one g has a pulse width of 3ms. So 100&micro;g would be 0.3&micro;s (not very long). The timer used would need to have a count time of half this (150ns) or less. With regards to "end of life," we have not been able to test to the level of accuracy you are describing. Getting to ~0.1 degree of dimensional stability in test platforms has been challenging, but that represents the level we have taken this too up to this point. We have reason to believe that the device will perform better, but believe the fixturing and test methods are handicapped in their ability to isolate true sensor behaviors. Based on the information I have, I can't offer assurance to the level of performance you seek on either ADIS16209 or ADXL213. I understand your approach to calibrating PCB shifts but my question was focused on planarity/flatness over temp cycles, moisture absorption, vibration, etc. 2um is a dimensional accuracy that took decades to accomplish at the silicon level. I am not saying this is impossible on PCBs, but I would not be surprised if it required consideration at some point. With regards to the ADC input, these typical values are normally pretty conservative and make some allowance for anticipated drifts, but keep in mind, they are listed as typicals, and not min/max limits. The only parting thought I would have regarding the ADIS16209 would center on its calibration over temperature and supply. While it was not targeted at the same performance level, you may find value in the first-order corrections for your pursuit of the tighter performance level over a more narrow temperature range.

Question 15

ADIS16209: How do I connect pins 7,8,10,11? There are contradictions in datasheet.

Accepted Answer

Q 
 There is some contradictory information in the ADiS16209 datasheet. While the pin configuration (Figure 5 ) states tha pins 7,8,10,11 are DNC (Do not connect), figure 23 shows a schematic for the ADIS16209/PCBZ with Pins 7,8,10 and 11 grounded at J2. Meanwhile the ADiS1620x/PCBZ datasheet figure 1 schematic shows pins 7,8,10 and 11 unconnected to J2. Which is correct? 
 
 A 
 The figure 23 schematic in dtatasheet is incorrect. Pins 7,8,10,11 should be not be connected to ground, These are DNC pins. Here is the correct schematic for the ADIS16209/PCB. The schematic in the datasheet figure 23 will be corrected shortly.

Question 16

ADIS16209 self-test

Accepted Answer

Q 
 We have a problem with the self-test of ADIS16209 at power-on. Is it correct that there is a possibility to disable this function at the power-on setting the bit 10 in the register MSC_CTRL? We have tried to do this but it was not possible to set this bit. So we also tried to set another bit (ie bit 1) to check if our write function works and we didn't have any problem. We would like to know if there is any problem with disabling self-test at power-on or there is any trick/workaround to do this. 
 
 A 
 Please check if you performed a flash update, after you set MSC_CTRL[10] = 1, but before you re-start the device. The flash update saves the setting in non-volatile flash memory, so that it will restore upon a power cycle or reset.

Question 17

ADIS16209 Datecode Revision Change

Accepted Answer

Q 
 What is the meaning of this &bdquo;R&ldquo; in the Datecode 1224R of the ADIS16209. 
 
 A 
 The &ldquo;R&rdquo; indicates that these units have had the firmware upgrade, so they would behave the same way as units with later date codes.

Question 18

ADIS16209 Datasheet Error; SPI Address Code Missing MSB

Accepted Answer

TITLE 
 ADIS16209 Datasheet Error; SPI Address Code Missing MSB

DOCUMENT 
 
 ADIS16209 Datasheet

REVISION 
 E

LOCATION 
 Page 6 (PDF) : Figure 3, Figure 4

DESCRIPTION 
 
 The address code in the SPI protocol is missing its most significant bit.

SOLUTION 
 
 The next revision of this datasheet will insert " A6 " into the two areas of yellow highlight. Until then, please be assured that this bit is active and that you can read the PROD_ID register, using DIN = 0x4A00 to request the contents of this register (which will flow out on DOUT, during the following 16-bit SPI sequence).

Question 19

ADIS16209 Datasheet Error: Address code length

Accepted Answer

TITLE 
 ADIS16209 Datasheet Error: Address code length

DOCUMENT 
 
 ADIS16209 Datasheet

REVISION 
 E

LOCATION 
 Page 12 (click here), left column, first paragraph, line 8

DESCRIPTION 
 
 This references lists the address code length as 6-bits. It is actually 7-bits. This only matters if you are trying read the PROD_ID register.

SOLUTION 
 
 The next revision of this datasheet will replace the "6" (yellow highlight) with a "7." Until then, please be assured that this bit is active and that you can read the PROD_ID register, using DIN = 0x4A00 to request the contents of this register (which will flow out on DOUT, during the following 16-bit SPI sequence).

Question 20

ADIS16201 and ADIS16209 Pins 8 and 10 Grounded - Performance Issues

Accepted Answer

Q 
 I initially used the ADIS16201 in my design. I tied pins 8 and 10 to ground. Later, I redesigned my system and upgraded to the ADIS16209. Will ADIS16209 work even if pin 8 and 10 is connected to ground or do we need to modify the pcb? 
 
 A 
 The ADIS16201 and ADIS16209 are identical with respect to these pins. The ADIS16209 will function exactly the same as the ADIS16201 with pins 8 and 10 connected to ground.

Partner Forums

Partner Libraries

ADIS16209: FAQ