Datasheet

(ExpressedindBc)
DV
CM
DV
OUT
10
CMRR=20Log
(ExpressedindBc)
DV
SUP
DV
OUT
10
PSRR=20Log
10
S
N
P
THD = 10Log
P
SINAD 1.76
ENOB =
6.02
-
ADS41B29
ADS41B49
SBAS486E – NOVEMBER 2009–REVISED JULY 2012 www.ti.com
Effective Number of Bits (ENOB) – ENOB is a measure of the converter performance as compared to the
theoretical limit based on quantization noise.
(4)
Total Harmonic Distortion (THD) – THD is the ratio of the power of the fundamental (P
S
) to the power of the
first nine harmonics (P
D
).
(5)
THD is typically given in units of dBc (dB to carrier).
Spurious-Free Dynamic Range (SFDR) – 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).
Two-Tone Intermodulation Distortion – IMD3 is the ratio of the power of the fundamental (at frequencies f
1
and f
2
) to the power of the worst spectral component at either frequency 2f
1
– f
2
or 2f
2
– f
1
. 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 full-scale range.
DC Power-Supply Rejection Ratio (DC PSRR) – 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.
AC Power-Supply Rejection Ratio (AC PSRR) – AC PSRR is the measure of rejection of variations in the
supply voltage by the ADC. If ΔV
SUP
is the change in supply voltage and ΔV
OUT
is the resultant change of the
ADC output code (referred to the input), then:
(6)
Voltage Overload Recovery – The number of clock cycles taken to recover to less than 1% error after an
overload on the analog inputs. This is tested by separately applying a sine wave signal with 6dB positive and
negative overload. The deviation of the first few samples after the overload (from the expected values) is noted.
Common-Mode Rejection Ratio (CMRR) – CMRR is the measure of rejection of variation in the analog input
common-mode by the ADC. If ΔV
CM_IN
is the change in the common-mode voltage of the input pins and ΔV
OUT
is
the resulting change of the ADC output code (referred to the input), then:
(7)
Crosstalk (only for multi-channel ADCs) – This is a measure of the internal coupling of a signal from an
adjacent channel into the channel of interest. It is specified separately for coupling from the immediate
neighboring channel (near-channel) and for coupling from channel across the package (far-channel). It is usually
measured by applying a full-scale signal in the adjacent channel. Crosstalk is the ratio of the power of the
coupling signal (as measured at the output of the channel of interest) to the power of the signal applied at the
adjacent channel input. It is typically expressed in dBc.
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