MAX1036 Maxim, MAX1036 Datasheet - Page 21

• Manufacturer Part Number: MAX1036
• Description: 2.7V to 5.5V / Low-Power / 4-/12-Channel 2-Wire Serial 8-Bit ADCs
• Manufacturer: Maxim

In reality, there are other noise sources besides quanti-
zation noise, including thermal noise, reference noise,
clock jitter, etc. Therefore, SNR is computed by taking
the ratio of the RMS signal to the RMS noise, which
includes all spectral components minus the fundamen-
tal, the first five harmonics, and the DC offset.
Signal-to-noise plus distortion (SINAD) is the ratio of the
fundamental input frequency’s RMS amplitude to RMS
equivalent of all other ADC output signals.
Effective number of bits (ENOB) indicates the global
accuracy of an ADC at a specific input frequency and
sampling rate. An ideal ADC’s error consists of quanti-
zation noise only. With an input range equal to the
ADC’s full-scale range, calculate the ENOB as follows:
SINAD (dB) = 20
TOP VIEW
ENOB = (SINAD - 1.76) / 6.02
AIN3/REF
AIN0
AIN1
AIN7
AIN6
AIN5
AIN4
AIN3
AIN2
AIN1
AIN0
AIN2
Signal-to-Noise Plus Distortion
______________________________________________________________________________________
1
2
6
3
4
5
7
8
1
2
4
3
2.7V to 5.5V, Low-Power, 4-/12-Channel
✕
log (Signal
Effective Number of Bits
MAX1038
MAX1039
MAX1036
MAX1037
SOT23
QSOP
Pin Configurations
16
15
14
13
12
11
10
6
RMS
8
7
5
9
V
GND
SDA
SCL
AIN8
AIN9
AIN10
AIN11/REF
V
GND
SDA
SCL
DD
DD
/ Noise
RMS
)
2-Wire Serial 8-Bit ADCs
Total harmonic distortion (THD) is the ratio of the RMS
sum of the input signal’s first five harmonics to the fun-
damental itself. This is expressed as:
where V
V
harmonics.
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.
MAX1036/MAX1037 TRANSISTOR COUNT: 6283
MAX1038/MAX1039 TRANSISTOR COUNT: 7257
PROCESS: BiCMOS
5
are the amplitudes of the 2nd- through 5th-order
THD
ANALOG
INPUTS
1
=
is the fundamental amplitude, and V
20
*OPTIONAL
×
log
Typical Operating Circuit
AIN0
AIN1
AIN2
AIN3/REF
Spurious-Free Dynamic Range







Total Harmonic Distortion
V
MAX1036
MAX1037
MAX1038
MAX1039
2
GND
V
2
µC
5V
5V
DD
+
Chip Information
V
3
SDA
2
SCL
+
5V
SDA
SCL
V
4
2
+
R
R
*R
*R
P
P
V
S
S
5
2



2
/
through
V
1




21