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Original question:

ADS8568: Gain error and gain error drift when external input to REFAP,REFBP,REFCP,REFDP

ADS8568: Specific Parameter Understanding (data rate & sampling rate)

Matt Qi
Intellectual 2760 points
Part Number: ADS8568
Other Parts Discussed in Thread: ADS8528

Hi,

My customer wants to know the specific parameters of the ADS8568:

1. The ADS85x8 series is an 8-channel ADC. What does it mean in the specification that the maximum data rate per channel is 510kSPS? According to the specification, the 8 channels are divided into 4 conversion pairs. Before the conversion pairs, they communicate in serial order. I would like to ask whether the parameter 510kSPS refers to the data rate when only one conversion pair is working or four conversion pairs. What is the maximum rate that each channel can achieve when all data is transmitted?

2. My customers do not understand the conversion. From the block diagram, we can see that CH_A0 and CH_A1 are the same conversion pair. Does it mean that the sampling and conversion on the two channels are completely synchronized?

3. Finally, confirm one more point: According to the records in the specification, whether it can be understood that the maximum rate of ADS8568 signal acquisition is 650kSPS, and the maximum transmission rate is 510kSPS?

Thanks, and looking forward for your reply~

  • 0
    TI__Guru**** 175201 points

    Hi Matt,

    1.) The ADS85x8 devices have two interface modes - parallel and serial.  When running in parallel mode, you can achieve the highest throughput.  For the ADS8568, that would be 510 kSPS per channel.  Figure 38 above shows sequential triggering of the four CONVST inputs. This is not the same thing as serial mode operation, please refer to pages 18 and 19 for a review of the two interface modes

    2.) Each channel pair is synchronized to its CONVST x pin.  You can tie all four CONVST inputs together on the ADS85x8 and all eight channels will simultaneously sample and convert at 510 kSPS per channel (in parallel mode) or 400 kSPS per channel when using the serial mode of operation. 

    3.) The ADS8528 can operate at 650 kSPS per channel in parallel mode, the ADS8568 can operate at 510 kSPS per channel in parallel mode.