Hi Andrey, Here is the correspondence that we've had with Analog Devices. It appears that our ADIS has been damaged - probably from the first 6.3V we applied. So, should we send it to you along with the camera/IMU board, or should you use your own IMU?
Remember that the voltage in the 103695 is still strange - 4.3V unloaded, 3.6V loaded - so I do not believe our problem is the ADIS. At least, not the whole problem. So its still worthwhile to have the 103695 repaired. We'll try to get Analog Devices to repair the ADIS, but we might need to buy a new one. Either option will take a few weeks I think. I'd rather get you the 103695 board now, rather than later. I'm out until Monday. I'll try to ship things to you then. Lee -----Original Message----- From: Looney, Mark [mailto:[email protected]] Sent: Thursday, November 17, 2011 2:37 PM To: Gorgen, Justin E CIV SPAWARSYSCEN-PACIFIC, 52340; Lemay, Lee C CIV SPAWARSYSCEN-PACIFIC, 52340 Subject: RE: Spawar Systems Center; ADIS16375; current draw Hello Justin, At this point, I am not sure. It sounds like sneak path for 400mA of current. If this were resistive, this might make sense. As the voltage increases, the real current required by the ADIS16375 will go down, due to the internal power regulator and the resistive part will go up. That would explain little or no current change over the supplies. May want to check the supply at the pins, because the ADIS16375 will actually start working at 2.85V, if the supply is solid (and the transient doesn't cause it to droop). Let me get with the Design Engineer and get back to you. I am out until Tuesday so it may take 2-3 days. Best, Mark Mark Looney iSensor Application Engineer Analog Devices, Inc. -----Original Message----- From: Gorgen, Justin E CIV SPAWARSYSCEN-PACIFIC, 52340 [mailto:[email protected]] Sent: Thursday, November 17, 2011 5:25 PM To: Looney, Mark; Lemay, Lee C CIV SPAWARSYSCEN-PACIFIC, 52340 Subject: RE: Spawar Systems Center; ADIS16375; current draw Hi Mark, Yes, 600 mA is the steady current. We tested this by putting the ADIS16375 on the PCBZ and supplying voltage to it with a labratory dc power supply with a current meter in series with the PCBZ. The power supply reports load current, which agrees with the current meter's readings, so this probably isn't a calibration issue with our lab equipment. Also, the PCBZ without an ADIS plugged in draws no current, so our PCBZ does not have a short.. The behavior we observed from the ADIS16375 is as follows. 1. Starting from no power, we set the voltage on VDD to 3.0 Volts, at which point the ADIS draws 400 mA from VDD. At this point, the ADIS is not on ( it does not respond to SPI ). 2. We ramp the voltage VDD upwards from 3.0 volts to 3.4 volts. 3. The ADIS16375 doesn't start ( does not respond to SPI commands) until VDD reaches 3.35 Volts, at which point current jumps from 400mA to 600mA and the ADIS will now respond to SPI. 4. Now that the ADIS is awake, We ramp VDD down from 3.4 volts to 3.0 volts, the ADIS draws 600mA from VDD at all voltages between 3.0 and 3.4 Volts. It continues to respond to SPI at these VDD voltages, and continues to draw 600mA. Plugging the ADIS16375 into the USBZ, we can no longer observe the current draw, but the VDD is at 3.28 volts. All status registers, when viewed with the Analog Devices software, are normal. The accelerometer and gyro values being read from the ADIS16375 appear to be accurate. What are your thoughts, Mark? Thanks for your time. Sincerely, Justin Gorgen ________________________________ From: Looney, Mark [mailto:[email protected]] Sent: Thu 11/17/2011 1:04 PM To: Lemay, Lee C CIV SPAWARSYSCEN-PACIFIC, 52340 Cc: Gorgen, Justin E CIV SPAWARSYSCEN-PACIFIC, 52340 Subject: Spawar Systems Center; ADIS16375; current draw Hello Lee, Is that steady current? The ADIS16375 does have a large transient current at start-up, which can ready 1.5A for 400us, but should not be drawing that sort of current by itself. Where are you measuring this current? Regards, Mark Mark Looney iSensor Application Engineer Analog Devices, Inc. -----Original Message----- From: Lemay, Lee C CIV SPAWARSYSCEN-PACIFIC, 52340 [mailto:[email protected]] Sent: Thursday, November 17, 2011 2:45 PM To: Looney, Mark Cc: Gorgen, Justin E CIV SPAWARSYSCEN-PACIFIC, 52340 Subject: Spawar Systems Center; ADIS16375; current draw Hi Mark, We're using an ADIS 16375. It appears to function correctly when we interface to it with ADISUSBZ. However, we are concerned because it draws 600 mA of current under normal operation. This is above the rated 173 mA from the spec sheet. Should we be concerned, and do you have any recommendations about how we can fix this or replace the unit? I appreciate your time and help! Best Regards, Lee Lemay Engineer Spawar Systems Center, San Diego 53560 Hull Street San Diego, Ca. 92152 (619)553-8619
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