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ADS7951: SPI Clock Frequency between Master and Slave

Part Number: ADS7951
Other Parts Discussed in Thread: ADS7953, , ADS8166


I am trying to create a ADC module with ADS795x which has SCLK at 20MHz frequency. I want to be able to use this module with different development boards like Arduino, MSP430, RPI, ESP32 etc. My question whether these development boards can communicate with the ADS7953 which seems to a much higher clock?



  • Hello,

    The ADS7953 can have an SCLK signal up to 20MHz, but can be used at slower clock rates and work correctly.

    Note though that SCLK controls the sampling rate, which means that when the SCLK is slowed down the sampling rate will also be decreased.



  • Cynthia

    Between ADC using external SCLK and ADC that has internal clock which is better for low noise and high accuracy?



  • Hello Vijay,

    Your question is much too broad to be able to answer with a simple this one or that one.

    Overall, all devices will have a its performance spec-ed, as long as the device is used in a well performing circuit, you should be able to reflect datasheet performance.

    Not all devices use the clock signal to control sampling rate, the ADS7951 does but if you are interested in looking at other devices we can explore what is the best fit your application.

    Delta Sigma ADCs are commonly known to have different sampling rates vs throughout rate (communication rate)

    the ADS8330 is a SAR device that can use the external SCLK clock signal to control the throughput rate and the sampling rate OR only the throughput rate and an internal oscillator controls the sampling rate of the device.

    Let me know if this is something you would like to explore.

    I would also like to share some material available online that could be helpful if you would like to learn amore about the topic. TI has put together a compilation of education videos under the title of Precision Labs, where different device types are covered, one being ADC and High Speed ADCs.

    The Impact of jitter on SNR for High Speed ADC



  • Thank you Cynthia. I have decided to use ADS8166 which has internal oscillator and comparably cheaper.