Rainbow Electronics MAX1081 - Manual (Page 22)

Signal-to-Noise Plus Distortion (SINAD)
SINAD is the ratio of the fundamental input frequency’s
RMS amplitude to RMS equivalent of all other ADC out-
put signals:
SINAD (dB) = 20 ✕ log (Signal RMS / Noise RMS )
Effective Number of Bits (ENOB)
ENOB indicates the global accuracy of an ADC at a
specific input frequency and sampling rate. An ideal
ADC’s error consists only of quantization noise. With an
input range equal to the ADC’s full-scale range, calcu-
late ENOB as follows:
ENOB = (SINAD - 1.76) / 6.02
Total Harmonic Distortion (THD)
THD is the ratio of the RMS sum of the input signal’s
first five harmonics 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 (SFDR)
SFDR is the ratio of the RMS amplitude of the funda-
mental (maximum signal component) to the RMS value
of the next-largest distortion component.
THD 20 log
V V V V V
V
2
2
3
2
4
2
4
2
5
2
1
= ×
+ + + +

 

MAX1080/MAX1081
300ksps/400ksps, Single-Supply, Low-Power,
8-Channel, Serial 10-Bit ADCs with Internal Reference
22 ______________________________________________________________________________________
SCLK
DIN
DOUT
SSTRB
SEL2 START SEL1 SEL0 PD1 PD0
CS
UNI/BIP SGI/DIF
B8 S1 MSB S0
HIGH IMPEDANCE
HIGH IMPEDANCE
Figure 19. MAX1080/MAX1081-to-TMS320 Serial Interface
PART
TEMP.
RANGE
PIN-
PACKAGE
MAX1080BEUP
MAX1081AEUP
MAX1081BEUP -40°C to +85°C
-40°C to +85°C
-40°C to +85°C 20 TSSOP
20 TSSOP
20 TSSOP
±1
±1/2
INL
(LSB)
±1
MAX1081ACUP
MAX1081BCUP 0°C to +70°C
0°C to +70°C 20 TSSOP
20 TSSOP
±1/2
±1
Ordering Information (continued)
Typical Operating Circuit
V
DD
I/O
SCK (SK)
MOSI (SO)
MISO (SI)
V SS
SHDN
SSTRB
DOUT
DIN
SCLK
CS
COM
GND
V DD1
V DD2
CH7
4.7 µF
0.1 µF
CH0
0 TO
+2.5V
ANALOG
INPUTS
MAX1080
MAX1081
CPU
+5V OR
+3V
REF
0.01 µF
REFADJ
V DD2
Chip Information
TRANSISTOR COUNT: 4286
PROCESS: BiCMOS