Multiple questions about ADPD105 and ADPD108 and their evalboards

I work for a Medical device R&D company. We are currently working on a project where we are trying to detect physiological signals deep under the skin using IR which requires an emitter to detector distance of 4+ cm. Because of this, we need to use a large amount of current through the emitter to get deep enough and your ADPD10X components look like they could work. I got the eval board for the ADPD105 but it doesn't seem to let you use all the functions the chip has to offer. I wanted to try the digital integration mode but when I do the graph doesn't work. So first off, I am wondering if I am doing something wrong or if the eval only allows limited use. Second, I noticed you now have the new ADPD108 that is recomended for new designs but the datasheet looks the same as the ADPD105 so I was wondering what the difference is. lastly, when I looked at the datasheet for the eval board for the ADPD108, the schematic shows an ADPD107 but the text says ADPD108. I am just a little confused about that. Also, How can I obtain an eval board for the ADPD108, there is no buy option.

Thanks

  • Hello,

    The digital integrate mode should have no problem working with the Wavetool software so I suspect you have something in your configuration that is not right. At the bottom of the email I've attached a set of register writes for using digital integrate in timeslot B. Which evaluation board and wavetool version are you using?

    The ADPD1080 has better noise and power performance than the ADPD105. It also has the addition of float mode which is described in the datasheet and is an excellent operating mode for very low CTR conditions. However, the ADPD1080 does not support digital integrate mode so if you are convinced you would like to use that mode then you would need to stick with the ADPD105. Either way, we have found no performance benefits to using digital integrate unless you have a very low bandwidth sensor that requires long LED pulses. The ADPD10x series is optimized for the best performance with short LED pulses of 2us or 3us. This also gives the best ambient light rejection.

    Regards,

    Kevin

    00 0000
    01 00FF
    02 0005
    06 0700
    09 00C8
    10 0000
    11 3120
    12 0050
    14 0115
    15 0110
    18 1FE0
    19 3FFF
    1A 3FFF
    1B 3FFF
    1E 0000
    1F 3FFF
    20 3FFF
    21 3FFF
    22 3030
    23 1035
    24 3030
    25 02D0
    30 0219
    31 0813
    34 0000
    35 0825
    36 0840
    38 0000
    39 19F4
    3B 6214
    3C 7006
    42 1C36
    43 ADA5
    44 1D35
    45 AE65
    4B 269A
    4D 005E
    4E 0040
    4F 20D0
    50 0040
    54 8AA0
    55 E000
    58 2000
    5A 0040
    5F 0001
    3E 0320
    37 0000
    3F 0320
    59 6808
    5E 6808

  • Device has some really interesting features:

    • Multifunction photometric front end
    • Fully integrated AFE, ADC, LED drivers, and timing core
    • Enables best-in-class ambient light rejection capability without the need for photodiode optical filters
    • Three 370 mA LED drivers
    • Flexible, multiple, short LED pulses per optical sample
    • 20-bit burst accumulator enabling 20 bits per sample period
    • On-board sample to sample accumulator, enabling up to 27 bits per data read
    • Low power operation
    • SPI, I2C interface, and 1.8 V analog/digital core
    • Flexible sampling frequency ranging from 0.122 Hz to 3820 Hz
    • FIFO data operation
  • I believe these stats are pretty good for ADPD105:

    • Multifunction photometric front end
    • Fully integrated AFE, ADC, LED drivers, and timing core
    • Enables best-in-class ambient light rejection capability without the need for photodiode optical filters
    • Three 370 mA LED drivers
    • Flexible, multiple, short LED pulses per optical sample
    • 20-bit burst accumulator enabling 20 bits per sample period
    • On-board sample to sample accumulator, enabling up to 27 bits per data read
    • Low power operation
    • SPI, I2C interface, and 1.8 V analog/digital core
    • Flexible sampling frequency ranging from 0.122 Hz to 3820 Hz
    • FIFO data operation