AD9878BST Analog Devices Inc, AD9878BST Datasheet - Page 13

• Manufacturer Part Number: AD9878BST
• Description: IC FRONT-END MIXED-SGNL 100-LQFP
• Manufacturer: Analog Devices Inc

Specifications of AD9878BST

• Rohs Status: RoHS non-compliant
• Number Of Bits: 12
• Number Of Channels: 4
• Power (watts): 673mW
• Voltage - Supply, Analog: 3.3V
• Voltage - Supply, Digital: 3.3V
• Package / Case: 100-LQFP

TERMINOLOGY
Differential Nonlinearity Error (DNL, No Missing Codes)
An ideal converter exhibits code transitions that are exactly 1 LSB
apart. DNL is the deviation from this ideal value. No missing
codes indicates that all of the ADC codes must be present over
all operating ranges.
Integral Nonlinearity Error (INL)
Linearity error refers to the deviation of each individual code from
a line drawn from negative full scale through positive full scale.
The point used as negative full scale occurs ½ LSB before the first
code transition. Positive full scale is defined as a level 1½ LSB
beyond the last code transition. The deviation is measured from
the middle of each code to the true straight line.
Phase Noise
Single-sideband, phase-noise power is specified relative to the
carrier (dBc/Hz) at a given frequency offset (1 kHz) from the
carrier. Phase noise can be measured directly in single-tone
transmit mode with a spectrum analyzer that supports noise
marker measurements. It detects the relative power between
the carrier and the offset (1 kHz) sideband noise and takes
the resolution bandwidth (RBW) into account by subtracting
10 × log(RBW). It also adds a correction factor that compensates
for the implementation of the resolution bandwidth, log display,
and detector characteristic.
Output Compliance Range
The range of allowable voltage at the output of a current-output
DAC. Operation beyond the maximum compliance limits can
cause either output stage saturation or breakdown, resulting in
nonlinear performance.
Spurious-Free Dynamic Range (SFDR)
The difference, in dB, between the rms amplitude of the DAC
output signal (or ADC input signal) and the peak spurious signal
over the specified bandwidth (Nyquist bandwidth, unless
otherwise noted).
Pipeline Delay (Latency)
The number of clock cycles between conversion initiation and
the associated output data being made available.
Offset Error
The first code transition should occur at an analog value ½ LSB
above negative full scale. Offset error is defined as the deviation
of the actual transition from that point.
Gain Error
The first code transition should occur at an analog value ½ LSB
above negative full scale. The last transition should occur for an
analog value 1½ LSB below the nominal full scale. Gain error
is the deviation of the actual difference between first and last
code transitions and the ideal difference between first and last
code transitions.
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Aperture Delay
The aperture delay is a measure of the sample-and-hold amplifier
(SHA) performance that specifies the time delay between the
rising edge of the sampling clock input and when the input
signal is held for conversion.
Aperture Jitter
Aperture jitter is the variation in aperture delay for successive
samples and is manifested as noise on the input to the ADC.
Input Referred Noise
The rms output noise is measured using histogram techniques.
The standard deviation of the ADC output codes is calculated
in LSB, and converted to an equivalent voltage. This results in a
noise figure that can be directly referred to the input of the MxFE.
Signal-to-Noise and Distortion (SINAD) Ratio
SINAD is the ratio of the rms value of the measured input signal
to the rms sum of other spectral components below the Nyquist
frequency, including harmonics, but excluding dc. The value for
SINAD is expressed in decibels.
Effective Number of Bits (ENOB)
For a sine wave, SINAD can be expressed in terms of the number
of bits. Using the following formula, it is possible to get a measure
of performance expressed as N, the effective number of bits:
Thus, the effective number of bits for a device for sine wave
inputs at a given input frequency can be calculated directly
from its measured SINAD.
Signal-to-Noise Ratio (SNR)
SNR is the ratio of the rms value of the measured input signal
to the rms sum of other spectral components below the Nyquist
frequency, excluding harmonics and dc. The value for SNR is
expressed in decibels.
Total Harmonic Distortion (THD)
THD is the ratio of the rms sum of the first six harmonic
components to the rms value of the measured input signal.
It is expressed as a percentage, or in decibels.
Power Supply Rejection
Power supply rejection specifies the converter’s maximum full-
scale change when the supplies are varied from nominal to
minimum or maximum specified voltages.
Channel-to-Channel Isolation (Crosstalk)
In an ideal multichannel system, the signal in one channel does
not influence the signal level of another channel. The channel-
to-channel isolation specification is a measure of the change
that occurs in a grounded channel as a full-scale signal is
applied to another channel.
N
= SINAD
(
−
. 1
76
)
dB
. 6
02
AD9878