Rainbow Electronics MAX1421 - Manual (Page 14)

MAX1421
error specification of less than 1LSB guarantees no
missing codes.
Dynamic Parameter Definitions
Aperture Jitter
Figure 10 depicts the aperture jitter (t AJ ), which is the
sample-to-sample variation in the aperture delay.
Aperture Delay
Aperture delay (t AD ) is the time defined between the
falling edge of the sampling clock and the instant when
an actual sample is taken (Figure 10).
Signal-to-Noise Ratio (SNR)
For a waveform perfectly reconstructed from digital
samples, the theoretical maximum 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 quantiza-
tion error only and results directly from the ADCs reso-
lution (N-bits):
SNR (MAX) = (6.02 ✕ N + 1.76)dB
In reality, there are other noise sources besides quanti-
zation noise e.g., 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 spec-
tral components minus the fundamental, the first four
harmonics, and the DC offset.
12-Bit, 40Msps, +3.3V, Low-Power ADC
with Internal Reference
14 ______________________________________________________________________________________
INPUT
300 Ω
-5V
+5V
0.1 µF
0.1 µF
0.1 µF
0.1 µF
C IN *
22pF
1nF 0.22 µF
44pF*
R ISO
50 Ω
R ISO
50 Ω
-5V
600 Ω
300 Ω
300 Ω
INP
INN
LOWPASS FILTER
CML
600 Ω
+5V
-5V
0.1 µF
300 Ω
300 Ω
600 Ω
300 Ω
0.1 µF
0.1 µF
0.1 µF
+5V
0.1 µF
300 Ω
MAX4108
MAX1421
MAX4108
MAX4108
LOWPASS FILTER
*TWO C IN (22pF) CAPS MAY BE REPLACED BY
ONE 44pF CAP, TO IMPROVE PERFORMANCE.
C IN *
22pF
Figure 7. Typical Application Circuit for Single-Ended to Differential Conversion