Datasheet

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Signal-to-Noise Ratio
SNR + 10Log
10
P
s
P
N
(4)
Signal-to-Noise and Distortion (SINAD)
SINAD + 10Log
10
P
s
P
N
) P
D
(5)
Effective Number of Bits (ENOB)
ENOB +
SINAD * 1.76
6.02
(6)
Total Harmonic Distortion (THD)
THD + 10Log
10
P
s
P
N
(7)
Spurious-Free Dynamic Range (SFDR)
Two-Tone Intermodulation Distortion
DC Power Supply Rejection Ratio (DC PSRR)
ADS6145, ADS6144
ADS6143, ADS6142
SLWS198B – JULY 2007 – REVISED MARCH 2008
SNR is the ratio of the power of the fundamental (P
S
) to the noise floor power (P
N
), excluding the power at dc
and the first nine harmonics.
SNR is either given in units of dBc (dB to carrier) when the absolute power of the fundamental is used as the
reference, or dBFS (dB to full scale) when the power of the fundamental is extrapolated to the converter ’ s
full-scale range.
SINAD is the ratio of the power of the fundamental (P
S
) to the power of all the other spectral components
including noise (P
N
) and distortion (P
D
), but excluding dc.
SINAD is either given in units of dBc (dB to carrier) when the absolute power of the fundamental is used as the
reference, or dBFS (dB to full scale) when the power of the fundamental is extrapolated to the converter ’ s
full-scale range.
The ENOB is a measure of a converter ’ s performance as compared to the theoretical limit based on quantization
noise.
THD is the ratio of the power of the fundamental (P
S
) to the power of the first nine harmonics (P
D
).
THD is typically given in units of dBc (dB to carrier).
The ratio of the power of the fundamental to the highest other spectral component (either spur or harmonic).
SFDR is typically given in units of dBc (dB to carrier).
IMD3 is the ratio of the power of the fundamental (at frequencies f1 and f2) to the power of the worst spectral
component at either frequency 2f1 – f2 or 2f2 – f1. IMD3 is either given in units of dBc (dB to carrier) when the
absolute power of the fundamental is used as the reference, or dBFS (dB to full scale) when the power of the
fundamental is extrapolated to the converter ’ s full-scale range.
The DC PSSR is the ratio of the change in offset error to a change in analog supply voltage. The DC PSRR is
typically given in units of mV/V.
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Product Folder Link(s): ADS6145, ADS6144 ADS6143, ADS6142