MAX11329–MAX11332
3Msps, 12-/10-Bit, 8-/16-Channel ADCs with
Post-Mux External Signal Conditioning Access
In reality, there are other noise sources besides quantiza-
tion noise, including thermal noise, reference noise, clock
Definitions
jitter, etc. Therefore, SNR is computed by taking the ratio
of the RMS signal to the RMS noise, which includes all
Integral Nonlinearity
Integral nonlinearity (INL) is the deviation of the values
spectral components minus the fundamental, the first five
on an actual transfer function from a straight line. This
harmonics, and the DC offset.
straight line can be either a best-straight-line fit or a line
drawn between the end points of the transfer function,
Total Harmonic Distortion
once offset and gain errors have been nulled. The static
linearity parameters for the MAX11329–MAX11332 are
measured using the end-points method.
Total harmonic distortion (THD) is expressed as:
2
2
2
2
5
V
+ V + V + V
3 4
2
THD = 20 × log
V
Differential Nonlinearity
Differential nonlinearity (DNL) is the difference between
an actual step width and the ideal value of 1 LSB. A DNL
error specification of 1 LSB or less guarantees no miss-
ing codes and a monotonic transfer function.
1
where V is the fundamental amplitude, and V through V
5
1
2
are the amplitudes of the 2nd- through 5th-order harmonics.
Spurious-Free Dynamic Range
Spurious-free dynamic range (SFDR) is the ratio of the
RMS amplitude of the fundamental (maximum signal
component) to the RMS value of the next largest distor-
tion component.
Signal-to-Noise Ratio
Signal-to-noise ratio is the ratio of the amplitude of the
desired signal to the amplitude of noise signals at a
given point in time. The larger the number, the better. The
theoretical minimum analog-to-digital noise is caused by
quantization error and results directly from the ADC’s
resolution (N bits):
Full-Power Bandwidth
Full-power bandwidth is the frequency at which the input
signal amplitude attenuates by 3dB for a full-scale input.
SNR = (6.02 x N + 1.76) dB
Table 15. Recommended Input Amplifiers
REFERENCE
MAX4430
MAX4432
MAX4454
MAX4418
MAX44263
CHANNELS
TYPICAL APPLICATION
1
2
4
4
2
Dual supply, low noise, low distortion, high bandwidth
Dual supply, low noise, low distortion, high bandwidth
Low power, single, supply, low cost
Low noise, low power, high bandwidth
Low power, precision, CMOS input, rail-to-rail I/O
Table 16. Recommended References
REFERENCE
TYPICAL APPLICATION
MAX6126
MAX6033
MAX6043
MAX6129B
MAX6003
Ultra-high precision, ultra-low noise, wide temperature range
Ultra-high precision, low noise, low power, wide temperature range
High precision, wide temperature range
Low cost, ultra-low power
Low cost, low power
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