TSA1201
DEFINITIONS OF SPECIFIED PARAMETERS
STATIC PARAMETERS
Static measurements are performed through
method of histograms on a 2MHz input signal,
sampled at 50Msps, which is high enough to fully
characterize the test frequency response. The
input level is +1dBFS to saturate the signal.
Differential Non Linearity (DNL)
The average deviation of any output code width
from the ideal code width of 1LSB.
Integral Non linearity (INL)
An ideal converter presents a transfer function as
being the straight line from the starting code to the
ending code. The INL is the deviation for each
transition from this ideal curve.
DYNAMIC PARAMETERS
Dynamic measurements are performed by
spectral analysis, applied to an input sinewave of
various frequencies and sampled at 50Msps.
Spurious Free Dynamic Range (SFDR)
The ratio between the power of the worst spurious
signal (not always an harmonic) and the amplitude
of fundamental tone (signal power) over the full
Nyquist band. It is expressed in dBc.
Total Harmonic Distortion (THD)
The ratio of the rms sum of the first five harmonic
distortion components to the rms value of the
fundamental line. It is expressed in dB.
Signal to Noise Ratio (SNR)
The ratio of the rms value of the fundamental
component to the rms sum of all other spectral
components in the Nyquist band (f
s
/2)
excluding
DC, fundamental and the first five harmonics.
SNR is reported in dB.
Signal to Noise and Distorsion Ratio (SINAD)
Similar ratio as for SNR but including the harmonic
distortion components in the noise figure (not DC
signal). It is expressed in dB.
From the SINAD, the Effective Number of Bits
(ENOB) can easily be deduced using the formula:
SINAD= 6.02
×
ENOB + 1.76 dB.
When the applied signal is not Full Scale (FS), but
has an A
0
amplitude, the SINAD expression
becomes:
SINAD= 6.02
×
ENOB + 1.76 dB + 20 log (2A
0
/FS)
The ENOB is expressed in bits.
Analog Input Bandwidth
The maximum analog input frequency at which the
spectral response of a full power signal is reduced
by 3dB. Higher values can be achieved with
smaller input levels.
Effective Resolution Bandwidth (ERB)
The band of input signal frequencies that the ADC
is intended to convert without loosing linearity i.e.
the maximum analog input frequency at which the
SINAD is decreased by 3dB or the ENOB by 1/2
bit.
Pipeline delay
Delay between the initial sample of the analog
input and the availability of the corresponding
digital data output,on the output bus. Also called
data latency. It is expressed as a number of clock
cycles.
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STMICROELECTRONICS [ STMICROELECTRONICS ]
