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PLABS-SAR-EVM-PDK: incorrect range of conversion values.

Tom Harkaway
Prodigy 30 points
Part Number: PLABS-SAR-EVM-PDK
Other Parts Discussed in Thread: OPA320

Purchased a PLABS-SAR-EVM kit to use with the Precision Lab Pro seminar. Everything seems to work, except the range of the converted data. I have the PSi Controls set for 2 Vpp Amplitude, 1.5 V DC Offset, Single Ended Output. after clicking on Update, the sliders to the right show the proper 0.5V to 2.5V range. After pressing the Capture button, the graph and the Min and Max values are shown as 0.300V to 1.299V. I verified that the output signal of the PSI is a 2KHz 2 Vpp sign offset by 1.5V.

The unit looks like it was a returned/refurbished unit as all the static back had new anti-static stickers, but I could see the old ones.

  • 0
    TI__Mastermind 45365 points

    Hello Tom,

    Thanks for query on E2E forum.

    Can you please let me know which channel on mother board and which coupon board you are using? what's your jumper settings on PSI and EVM mother board? thanks.

    We did upgrade for all hardware kits with few changes in early this year,tha's why you saw a new sticker on ESD bag, we guarantee the EVM-PDK you received is new, and it's not a returned/refurbished unit. I apologized for this confusion to you.

    Best regards

    Dale

  • 0 in reply to Dale Li
    Prodigy 30 points

    I am using Channel 1 on the mother board.

    The coupon board is the OPA320_Good Filter 1

    Jumpers on the PSI:  JP1: Flt;    JP3: Flt;    JP4: SE_VCM;    JP8: GND

    Jumpers on the Motherboard: between Channels 1 & 2: DC_IN; S1: down (away from PHI_CH1 label

    As I mentioned I looked at the output of the PSI using an oscilloscope between SE and GND2 test-points. Everything there looked good, reflecting changes made in the PSI control panel. 

  • 0 in reply to Tom Harkaway
    TI__Mastermind 45365 points

    Hi Tom,

    "AC_IN" on the mother board should be selected with a jumper for your this test on CH1 (or CH2) because you are applying a AC input signal to CH1. DC_IN is only used to check DC voltage on the mother board without any external signal.

    By the way, please keep original S1 setting on mother board and don't change its position for any test you will do, it's a same guideline for S2 and S3, because the default setting (low/down position when shipping from factory) for S1/S2/S3 are used to protect EEPROM in case any misoperation to change the content in EEPROM on Plabs mother board.

    Thanks.

    Best regards

    Dale

  • 0 in reply to Dale Li
    Prodigy 30 points
    Thanks. That worked. The label on the jumper is a little misleading. I was thinking it was a choice between AC or DC coupling. Had to re-read the guide and look at the schematic to see that the DC position provides a fixed DC value to the input.