Signal-to-Noise Plus Distortion

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

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:

Total Harmonic Distortion

Total harmonic distortion (THD) is the RMS sum ratio of

the input signal’s first five harmonics to the fundamental

itself, expressed as:

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.

Chip Information

TRANSISTOR COUNT: 18,269

PROCESS: BiCMOS

THD

=

×

















20

2

log

V+ V+ V

+ V

V

2

2

3

2

4

2

5

1

E

SINAD - 1.76

NOB =









602

.

SINAD db

(

)

log

=

×









20

Signal

Noise

RMS

RMS

58.6ksps, 14-Bit, 2-Wire Serial ADC

in a 14-Pin TSSOP

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