MAX1185 Maxim, MAX1185 Datasheet - Page 17

• Manufacturer Part Number: MAX1185
• Description: Dual 10-Bit / 20Msps / +3V / Low-Power ADC with Internal Reference and Multiplexed Parallel Outputs
• Manufacturer: Maxim

Figure 7: Using an Op Amp for Single-Ended, AC-Coupled Input Drive
quantization error (residual error). The ideal, theoretical
minimum analog-to-digital noise is caused by quantiza-
tion error only and results directly from the ADC’s reso-
lution (N-Bits):
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.
Internal Reference and Multiplexed Parallel Outputs
SNR
Dual 10-Bit, 20Msps, +3V, Low-Power ADC with
dB[max]
______________________________________________________________________________________
______________________________________________________________________________________
V
V
IN
IN
= 6.02
MAX4108
MAX4108
dB
x N + 1.76
100Ω
100Ω
100Ω
100Ω
dB
0.1µF
0.1µF
REFN
REFN
REFP
REFP
1kΩ
1kΩ
1kΩ
1kΩ
R
50Ω
R
50Ω
ISO
ISO
0.1µF
0.1µF
SINAD is computed by taking the ratio of the RMS sig-
nal to all spectral components minus the fundamental
and the DC offset.
ENOB specifies the dynamic performance of an ADC at
a specific input frequency and sampling rate. An ideal
ADCs error consists of quantization noise only. ENOB is
computed from:
C
22pF
C
22pF
Signal-to-Noise Plus Distortion (SINAD)
IN
IN
22pF
22pF
R
50Ω
C
50Ω
R
C
ISO
IN
ISO
IN
ENOB
Effective Number of Bits (ENOB)
INA+
COM
INA-
INB+
INB-
MAX1185
=
SINAD
6 02
dB
.
−
dB
1 76
.
dB
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