Functional diagram – Rainbow Electronics MAX1145 User Manual
Page 16
MAX1144/MAX1145
Signal-to-Noise Plus Distortion
Signal-to-noise plus distortion (SINAD) is the ratio of the
fundamental input frequency’s RMS amplitude to the
RMS equivalent of all other ADC output signals:
SINAD (dB) = 20 x log (Signal
RMS
/ Noise
RMS
)
Total Harmonic Distortion
Total harmonic distortion (THD) is the ratio of the RMS
sum of the first five harmonics of the input signal to the
fundamental itself. This is expressed as:
where V1 is the fundamental amplitude, and V2 through
V5 are the amplitudes of the 2nd- through 5th-order
harmonics.
Spurious-Free Dynamic Range
Spurious-free dynamic range (SFDR) is the ratio of RMS
amplitude of the fundamental (maximum signal compo-
nent) to the RMS value of the next largest distortion
component.
THD
V
V
V
V
V
=
×
+
+
+
20
2
2
3
2
4
2
5
2
1
log
14-Bit ADCs, 150ksps, 3.3V Single Supply
16
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Functional Diagram
CREF
AV
DD
AGND
REF
CS
RST
AIN
DV
DD
DGND
SCLK
DIN
ANALOG TIMING CONTROL
INPUT
SCALING
NETWORK
SERIAL
OUTPUT
PORT
SERIAL
INPUT
PORT
MEMORY
CALIBRATION
ENGINE
CLOCK
GENERATOR
CONTROL
DAC
COMPARATOR
P2
SSTRB
DOUT
P1
P0
SHDN
MAX1144
MAX1145