MAX1124 Maxim Integrated Products, MAX1124 Datasheet - Page 16

• Manufacturer Part Number: MAX1124
• Description: 250Msps Analog-to-Digital Converter
• Manufacturer: Maxim Integrated Products

with 100Ω characteristic impedance from the ADC to
the LVDS load device.
Integral nonlinearity is the deviation of the values on an
actual transfer function from a straight line. This straight
line can be either a best straight-line fit or a line drawn
between the end points of the transfer function, once
offset and gain errors have been nullified. However, the
static linearity parameters for the MAX1124 are mea-
sured using the histogram method with an input fre-
quency of 10MHz.
Differential nonlinearity is the difference between an
actual step width and the ideal value of 1 LSB. A DNL
error specification of less than 1 LSB guarantees no
missing codes and a monotonic transfer function. The
MAX1124’s DNL specification is measured with the his-
togram method based on a 10MHz input tone.
Figure
sample-to-sample variation in the aperture delay.
Aperture delay (t
falling edge of the sampling clock and the instant when
an actual sample is taken
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 ADC’s reso-
lution (N bits):
In reality, other noise sources such as thermal noise,
clock jitter, signal phase noise, and transfer function
nonlinearities are also contributing to the SNR calcula-
tion and should be considered when determining the
SNR in ADC.
SINAD is computed by taking the ratio of the RMS sig-
nal to all spectral components excluding the fundamen-
tal and the DC offset. In case of the MAX1124, SINAD
is computed from a curve fit.
1.8V, 10-Bit, 250Msps Analog-to-Digital Converter
with LVDS Outputs for Wideband Applications
16
______________________________________________________________________________________
Signal-to-Noise Plus Distortion (SINAD)
Dynamic Parameter Definitions
11 depicts the aperture jitter (t
Static Parameter Definitions
SNR
dB[max]
Differential Nonlinearly (DNL)
AD
Signal-to-Noise Ratio (SNR)
) is the time defined between the
Integral Nonlinearity (INL)
= 6.02
(Figure
dB
x N + 1.76
11).
Aperture Delay
Aperture Jitter
AJ
), which is the
dB
SFDR is the ratio of RMS amplitude of the carrier fre-
quency (maximum signal component) to the RMS value
of the next-largest noise or harmonic distortion compo-
nent. SFDR is usually measured in dBc with respect to
the carrier frequency amplitude or in dBFS with respect
to the ADC’s full-scale range.
The two-tone IMD is the ratio expressed in decibels of
either input tone to the worst 3rd-order (or higher) inter-
modulation products. The individual input tone levels
are at -7dB full scale.
Two-Tone Intermodulation Distortion (IMD)
Figure 11. Aperture Jitter/Delay Specifications
MAX1122
MAX1123
MAX1121
PART
Spurious-Free Dynamic Range (SFDR)
Pin-Compatible Higher Speed/
DATA (T/H)
SAMPLED
ANALOG
INPUT
CLKN
Lower Resolution Versions
CLKP
T/H
t
AD
TRACK
RESOLUTION
(Bits)
10
10
8
t
HOLD
AJ
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SPEED GRADE
TRACK
(Msps)
170
210
250