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ADS122C04: Timing information for turbo mode

Part Number: ADS122C04

Hi Team,

Good day. 

I have a question about the ADC ADS122c04. How long does it take in turbo mode at an output data rate of 1200 to measure all 4 inputs once?

Or how long does it take to switch from one input to the other. So how long does the multiplexing process take?

The main problem of our customer is that they don't get the exact timing information from the datasheet so they cannot approximate how long does it take to sample each channel.

Could you help us enlighten with this concern? Thanks in advance. 

Best regards,


  • Hi Jonathan,

    The data rate will scale directly with the internal oscillator.  From the Electrical Characteristics Table we see the following:

    In turbo mode the clock min/max can be as much as 4% of 2.048MHz.  This means that the 1200sps nominal data rate can vary as much as 4% as well.  Note that I just mentioned the nominal data rate.  The  actual conversion rate as numbers of clock periods is given in Table 12 of the ADS122C04 datasheet.

    Which timing you use depends on whether continuous mode or single-shot mode is used.  The fastest time to cycle through the mux would be to use continuous mode and monitor the DRDY signal to trigger an interrupt on the falling edge of DRDY.  As a part of the interrupt routine you would change the mux to the next channel which will restart the conversion and then you can issue the RDATA command to read the last conversion completed.  Aside from the data rate timing you would also need to add the timing of the register write command to change the mux.  The SCL clock should be set to fast+ timing (1MHz) to get the fastest throughput.

    So the worst case timing for conversion in continuous mode is [(1.04 * 0.84ms) + time to write the register for the mux change ] * 4.

    Best regards,

    Bob B

  • Hi Bob,

    Thank you. Our customer wanted to appreciate your very fast and very clear explanation. 

    Best regards,