MAX11047 Datasheet, PDF (18/18 Pages) Maxim Integrated Products – 4-/6-/8-Channel, 16-Bit, Simultaneous-Sampling ADCs

4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
Signal-to-Noise Ratio (SNR)
For a waveform perfectly reconstructed from digital
samples, SNR is the ratio of the full-scale analog input
(RMS value) to the RMS quantization error (residual
error). The ideal, theoretical minimum analog-to-digital
noise is caused by quantization noise error only and
results directly from the ADC’s resolution (N bits):
SNR = (6.02 x N + 1.76)dB
where N = 16 bits. In reality, there are other noise
sources besides quantization noise: thermal noise, ref-
erence noise, clock jitter, etc. SNR is computed by tak-
ing the ratio of the RMS signal to the RMS noise, which
includes all spectral components not including the fun-
damental, the first five harmonics, and the DC offset.
Signal-to-Noise Plus Distortion (SINAD)
SINAD is the ratio of the fundamental input frequency’s
RMS amplitude to the RMS equivalent of all the other
ADC output signals:
SINAD(dB)
=
10
×
log
⎡
⎢
⎣
Signal_RMS
(Noise + Distortion)_RMS
⎤
⎥
⎦
Effective Number of Bits (ENOB)
The ENOB indicates the global accuracy of an ADC at
a specific input frequency and sampling rate. An ideal
ADC’s error consists of quantization noise only. With an
input range equal to the full-scale range of the ADC,
calculate the ENOB as follows:
ENOB = ^{SINAD − 1.76}
6.02
Total Harmonic Distortion (THD)
THD is the ratio of the RMS of the first five harmonics of
the input signal to the fundamental itself. This is
expressed as:
⎡
THD = 20 × log ^⎢
V2 ²
+
V3 ²
+
V4 ²
+
V52
⎤
⎥
⎣⎢
V₁
⎦⎥
where V₁ is the fundamental amplitude and V₂ through
V₅ are the 2nd- through 5th-order harmonics.
Spurious-Free Dynamic Range (SFDR)
SFDR is the ratio of the RMS amplitude of the funda-
mental (maximum signal component) to the RMS value
of the next-largest frequency component.
Aperture Delay
Aperture delay (t_AD) is the time delay from the sampling
clock edge to the instant when an actual sample is
taken.
Aperture Jitter
Aperture Jitter (t_AJ) is the sample-to-sample variation in
aperture delay.
Channel-to-Channel Isolation
Channel-to-channel isolation indicates how well each
analog input is isolated from the other channels.
Channel-to-channel isolation is measured by applying
DC to channels 1 to 7, while a -0.4dBFS sine wave at
60Hz is applied to channel 0. A 10ksps FFT is taken for
channel 0 and channel 1. Channel-to-channel isolation
is expressed in dB as the power ratio of the two 60Hz
magnitudes.
Small-Signal Bandwidth
A small -20dBFS analog input signal is applied to an
ADC in a manner that ensures that the signal’s slew
rate does not limit the ADC’s performance. The input
frequency is then swept up to the point where the
amplitude of the digitized conversion result has
decreased 3dB.
Full-Power Bandwidth
A large -0.5dBFS analog input signal is applied to an
ADC, and the input frequency is swept up to the point
where the amplitude of the digitized conversion result
has decreased by 3dB. This point is defined as full-
power input bandwidth frequency.
Chip Information
PROCESS: BiCMOS
Package Information
For the latest package outline information and land patterns,
go to www.maxim-ic.com/packages. Note that a “+”, “#”, or
“-” in the package code indicates RoHS status only. Package
drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
PACKAGE TYPE PACKAGE CODE DOCUMENT NO.
56 TQFN-EP
T5688+2
21-0135
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