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We bought EVAL-ADPD188GG and everything works fine. Now we are trying to connect external LEDs / photodiodes, but the current (last) documentation (revision C) differs considerably from our board with revision D.
Could You please provide us an up-to-date schematics and description?

Thanks very much

  • Hi Dirk,

    The schematic of EVAL-ADPD188GG board (Rev. D) is the same as the Rev. C in the user guide  EVAL-ADPD188GGZ User Guide UG-1256. 

    To connect external PDs, you would need to make modifications to the EVAL-ADPD188GG board listed below:

    1. Remove R18 (0 ohms)

    2. Replace R3 (137k) and R7 (137k) with 0 ohm resistors

    You can then use the test points PD1 (EXT_IN1) and PD2 (EXT_IN2) for anode connection and PDC for cathode connection of external PDs.

    You can connect external LEDs to test points LEDX2 and LEDX3 (the two green LEDs are connected to LEDX1 in the ADPD188GG module). Please make sure you have proper power supply for your external LED(s).


    Glen B.

  • Dear Glen,

    thank You very much for answer. The external LED works well, but we still have problems with the schematic on pages 8 and 9 in the user guide (actual version Rev 0 from your website). The primary layer on page 9 is hard to read - we couldn't find R18. In the schematics on page 8 there is also no R18.

    1. where is R18 located?

    2. on page 9 we can see three sockets: P31, P32 and P33, but not in the schematic on page 8. What signals can we get on P31..P33?



  • Hi Dirk,

    Thanks for your feedback! It is great to learn that your external LED works.

    In addition to ADPD188GG (U1), the EVAL-ADPD188GGZ board has some experimental capacities, including ADXL362 (U2) for motion and AD8233 (U3) for a single lead ECG. AD8233 and related circuits are not in the schematic in the user guide.

    R18, P31, P32, and P33 are part of the AD8233 circuit, where R18 connects the AD8233 output to EXT_IN1 of ADPD188GG via R3 (137k) and P31/P32/P33 are for electrode connections. The locations of R18, P31, P32, P33 are marked in the attached picture of the EVAL-ADPD188GGZ.


    Glen B.