ꢌ ꢒꢊ ꢗꢗ ꢁꢘ
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SBAS308A− MAY 2004 − REVISED MARCH 2005
DEFINITION OF SPECIFICATIONS
Offset Error
Analog Bandwidth
The analog input frequency at which the power of the
fundamental is reduced by 3dB with respect to the low
frequency value.
The offset error is the difference, given in number of
LSBs, between the ADC’s actual average idle channel
output code and the ideal average idle channel output
code. This quantity is often mapped into mV.
Aperture Delay
Temperature Drift
The temperature drift coefficient (with respect to gain
error and offset error) specifies the change per degree
The delay in time between the falling edge of the input
sampling clock and the actual time at which the
sampling occurs.
celcius of the parameter from T
to T
. It is
MIN
MAX
Aperture Uncertainty (Jitter)
The sample-to-sample variation in aperture delay.
calcuated by dividing the maximum deviation of the
parameter across the T to T range by the
MIN
MAX
difference T
−T
.
MAX MIN
Clock Pulse Width/Duty Cycle
The duty cycle of a clock signal is the ratio of the time
the clock signal remains at a logic high (clock pulse
width) to the period of the clock signal. Duty cycle is
typically expressed as a percentage. A perfect
differential sine wave clock results in a 50% duty cycle.
Signal-to-Noise Ratio
SNR is the ratio of the power of the fundamental (P )
S
to the noise floor power (P ), excluding the power at DC
N
and the first eight harmonics.
PS
SNR + 10Log
10 PN
Maximum Conversion Rate
The maximum sampling rate at which certified
operation is given. All parametric testing is performed
at this sampling rate unless otherwise noted.
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.
Minimum Conversion Rate
The minimum sampling rate at which the ADC
functions.
Signal-to-Noise and Distortion (SINAD)
SINAD is the ratio of the power of the fundamental (P )
to the power of all the other spectral components
Differential Nonlinearity (DNL)
S
An ideal ADC exhibits code transitions at analog input
values spaced exactly 1LSB apart. The DNL is the
deviation of any single step from this ideal value,
measured in units of LSBs.
including noise (P ) and distortion (P ), but excluding
N
D
DC.
PS
SINAD + 10Log
10 PN ) PD
Integral Nonlinearity (INL)
The INL is the deviation of the ADC’s transfer function
from a best fit line determined by a least squares curve
fit of that transfer function, measured in units of LSBs.
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.
Gain Error
The gain error is the deviation of the ADC’s actual input
full-scale range from its ideal value. The gain error is
given as a percentage of the ideal input full-scale range.
Gain error does not account for variations in the internal
reference voltages (see the Electrical Specifications
Effective Number of Bits (ENOB)
The ENOB is a measure of a converter’s performance
as compared to the theoretical limit based on
quantization noise.
section for limits on the variation of V
and V
).
REFP
REFM
SINAD * 1.76
ENOB +
6.02
11
BB [ BURR-BROWN CORPORATION ]
