JAJSDZ9 October 2017 ADS54J64
PRODUCTION DATA.
The signal-to-noise ratio of the ADC is limited by three different factors (as shown in Equation 3): the quantization noise is typically not noticeable in pipeline converters and is 84 dB for a 14-bit ADC. The thermal noise limits the SNR at low input frequencies and the clock jitter sets the SNR for higher input frequencies.
Equation 4 calculates the SNR limitation resulting from sample clock jitter:
The total clock jitter (TJitter) has two components: the internal aperture jitter (100 fS for the ADS54J64) that is set by the noise of the clock input buffer and the external clock jitter. Equation 5 calculates TJitter:
External clock jitter can be minimized by using high-quality clock sources and jitter cleaners as well as band-pass filters at the clock input; a faster clock slew rate also improves the ADC aperture jitter.
The ADS54J64 has a thermal noise of approximately 70 dBFS and an internal aperture jitter of 100 fS.