• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 46 subscribers
  • Views 215 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ADS8588S: Questions about Read after conversion

ttd
Mastermind 8050 points
Part Number: ADS8588S
Other Parts Discussed in Thread: ADS8584S,

Tool/software:

Dear Technical Support Team,

I have questions about ADS8588S and ADS8584S.

Q1

The ADS8588S is equipped with an 8-channel ADC, but when reading only 4 channels (ch1 to ch4) in Read After Conversion, assert only “CONVSTA” to '1' and use “Figure 2. Data Read Operation Timing Diagram” and ‘Figure 4: Parallel Data Read Operation, CS and RD Separate’. (CONVSTB is fixed at '0' and not used)

Is it correct?

Q2

If I read only 4 channels with Q10, will the tCONV (Conversion Time) of ADS8588 take 3.7 to 3.9us?
Since tCONV of ADS8584 was 2us (Typ), I was wondering if it can be shortened.

Q3

If the ADS8588S installed in the ADS8588SEVM-PDK is replaced with the ADS8584S, is there any problem other than a decrease from 8 to 4 channels?
For example, is there any change in the pin assignment of the J9 connector pins on the board, or are there any pins that can no longer be used?

Best Regards,

ttd

  • 0
    TI__Guru**** 174346 points

    Hi ttd,

    For Q1 - yes, that is correct.  Read after conversion is done once BUSY is asserted low.

    For Q2 - you cannot change the conversion time.  The 3.7 to 3.9uS you sighted above is based on no oversampling using an internal conversion clock.

    For Q3 - the control lines are on the same pins, but the analog input channels have a slightly different pin configuration

  • 0 in reply to Tom Hendrick
    Mastermind 8050 points

    Hi Tom,

    The background of my question is that I'd like to process 1 sample(200Ksps) of data from a sensor within 5us inside FPGA. Since ADS8588S's conversion time accounts for about 4us of the 5us processing time, I would like to replace it with the ADS8584 Sto shorten the conversion time to 2us (Typ).

    The Conversion Time of ADS8588S with EVM is as long as 3.9us, so I have been looking for a way to shorten it by 200ksps,

    However from your answer, I recognized that there is no way to shorten it.

    If you have any advice on the above, please let me know.

    Best Regards,

    ttd

  • 0 in reply to ttd
    TI__Guru**** 174346 points

    Hi ttd,

    The ADS8584 is a faster ADC, so you should be able to achieve your goal with that device.