
MAX5893
However, noise sources such as thermal noise, refer-
ence noise, clock jitter, etc. affect the ideal reading.
Therefore, SNR is computed by taking the ratio of the
RMS signal to the RMS noise, which includes all spec-
tral components minus the fundamental, the first four
harmonics, and the DC offset.
Spurious-Free Dynamic Range (SFDR)
SFDR is the ratio of the RMS amplitude of the carrier
frequency (maximum signal components) to the RMS
value of their next largest distortion component. SFDR
is usually measured in dBc and with respect to the car-
rier frequency amplitude or in dBFS with respect to the
DAC’s full-scale range. Depending on its test condition,
SFDR is observed within a predefined window or
to Nyquist.
Two-/Four-Tone Intermodulation
Distortion (IMD)
The two-tone IMD is the ratio expressed in dBc (or
dBFS) of the worst 3rd-order (or higher) IMD products
to either output tone.
Adjacent Channel Leakage
Power Ratio (ACLR)
Commonly used in combination with WCDMA (wide-
band code-division multiple-access), ACLR reflects the
leakage power ratio in dB between the measured pow-
ers within a channel relative to its adjacent channel.
ACLR provides a quantifiable method of determining
out-of-band spectral energy and its influence on an
adjacent channel when a bandwidth-limited RF signal
passes through a nonlinear device.
12-Bit, 500Msps Interpolating and Modulating
Dual DAC with CMOS Inputs
30
______________________________________________________________________________________