Instruction Manual

MAX1198
Dual, 8-Bit, 100Msps, 3.3V, Low-Power ADC
with Internal Reference and Parallel Outputs
20 ______________________________________________________________________________________
In reality, there are other noise sources besides quanti-
zation noise: thermal noise, reference noise, clock jitter,
etc. SNR is computed by taking the ratio of the RMS
signal to the RMS noise, which includes all spectral
components minus the fundamental, the first five har-
monics, and the DC offset.
Signal-to-Noise Plus Distortion
SINAD is computed by taking the ratio of the RMS sig-
nal to all spectral components minus the fundamental
and the DC offset.
Effective Number of Bits
Effective number of bits (ENOB) specifies the dynamic
performance of an ADC at a specific input frequency
and sampling rate. An ideal ADC’s error consists of
quantization noise only. ENOB for a full-scale sinusoidal
input waveform is computed from:
Total Harmonic Distortion
THD is typically the ratio of the RMS sum of the first four
harmonics of the input signal to the fundamental itself.
This is expressed as:
where V
1
is the fundamental amplitude, and V
2
through
V
5
are the amplitudes of the 2nd- through 5th-order
harmonics.
Spurious-Free Dynamic Range
Spurious-free dynamic range (SFDR) is the ratio
expressed in decibels of the RMS amplitude of the fun-
damental (maximum signal component) to the RMS
value of the next largest spurious component, exclud-
ing DC offset.
Intermodulation Distortion
The two-tone intermodulation distortion (IMD) is the
ratio expressed in decibels of either input tone to the
worst third-order (or higher) intermodulation products.
The individual input tone levels are at -7dB full scale
and their envelope is at -1dB full scale.
THD
VVVV
V
log=×
+++
20
2
2
3
2
4
2
5
2
1
ENOB
SINAD .
.
=
−176
602
Chip Information
TRANSISTOR COUNT: 11,601
PROCESS: CMOS