AD7762 Analog Devices, AD7762 Datasheet - Page 9

• Manufacturer Part Number: AD7762
• Description: Parallel Interface, 625 kSPS, 24-Bit Sigma-Delta A/D Converter
• Manufacturer: Analog Devices

Specifications of AD7762

• Resolution (bits): 24bit
• # Chan: 1
• Sample Rate: 40MSPS
• Interface: Par
• Analog Input Type: Diff-Uni
• Ain Range: (1.6Vref) p-p,4 V p-p,6.5 V p-p
• Adc Architecture: Sigma-Delta
• Pkg Type: QFP

TERMINOLOGY
Signal-to-Noise Ratio (SNR)
SNR is the ratio of the rms value of the actual input signal to the
rms sum of all other spectral components below the Nyquist
frequency, excluding harmonics and dc. The value for SNR is
expressed in decibels.
Total Harmonic Distortion (THD)
The ratio of the rms sum of harmonics to the fundamental. For
the AD7762, it is defined as
where:
V
V
the sixth harmonics.
Nonharmonic Spurious-Free Dynamic Range (SFDR)
The ratio of the rms signal amplitude to the rms value of the
peak spurious spectral component, excluding harmonics.
Dynamic Range
Dynamic range is the ratio of the rms value of the full scale to
the rms noise measured with the inputs shorted together. The
value for dynamic range is expressed in decibels.
Integral Nonlinearity (INL)
The maximum deviation from a straight line passing through
the endpoints of the ADC transfer function.
1
2
, V
is the rms amplitude of the fundamental.
3
, V
4
THD
, V
5
,.and V
( )
dB
=
6
20
are the rms amplitudes of the second to
log
V
2
2
+
V
3
2
+
V
V
1
4
2
+
V
5
2
+
V
6
2
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Differential Nonlinearity (DNL)
The difference between the measured and the ideal 1-LSB
change between any two adjacent codes in the ADC.
Zero Error
The zero error is the difference between the ideal midscale
input voltage (0 V) and the actual voltage producing the
midscale output code.
Zero Error Drift
The change in the actual zero error value due to a temperature
change of 1°C. It is expressed as a percentage of the zero error at
room temperature.
Gain Error
The first transition (from 100…000 to 100…001) should occur
for an analog voltage 1/2 LSB above the nominal negative full
scale. The last transition (from 011…110 to 011…111) should
occur for an analog voltage 1 1/2 LSB below the nominal full
scale. The gain error is the deviation of the difference between
the actual level of the last transition and the actual level of the
first transition, from the difference between the ideal levels.
Gain Error Drift
The change in the actual gain error value due to a temperature
change of 1°C. It is expressed as a percentage of the gain error at
room temperature.
AD7762