2

1

f

2

6

f

2

2

f

10

‡

A

A

+

+

A

log

20

=

THD

ADC082S101

SNAS288C – APRIL 2005 – REVISED FEBRUARY 2010

www.ti.com

FULL POWER BANDWIDTH is a measure of the frequency at which the reconstructed output fundamental

drops 3 dB below its low frequency value for a full scale input.

FULL SCALE ERROR (FSE) is a measure of how far the last code transition is from the ideal 1½ LSB below

(1)

LSB or percent of full scale range.

LSB), after adjusting for offset error.

INTEGRAL NON-LINEARITY (INL) is a measure of the deviation of each individual code from a line drawn from

negative full scale (½ LSB below the first code transition) through positive full scale (½ LSB above the last code

transition). The deviation of any given code from this straight line is measured from the center of that code value.

INTERMODULATION DISTORTION (IMD) is the creation of additional spectral components as a result of two

sinusoidal frequencies being applied to the ADC input at the same time. It is defined as the ratio of the power in

the second and third order intermodulation products to the sum of the power in both of the original frequencies.

IMD is usually expressed in dB.

MISSING CODES are those output codes that will never appear at the ADC outputs. The ADC082S101 is

guaranteed not to have any missing codes.

OFFSET ERROR is the deviation of the first code transition (000...000) to (000...001) from the ideal (i.e. GND +

0.5 LSB).

SIGNAL TO NOISE RATIO (SNR) is the ratio, expressed in dB, of the rms value of the input signal at the

converter output to the rms value of the sum of all other spectral components below one-half the sampling

frequency, not including d.c. or harmonics included in the THD specification.

SIGNAL TO NOISE PLUS DISTORTION (S/N+D or SINAD) Is the ratio, expressed in dB, of the rms value of the

input signal to the rms value of all of the other spectral components below half the clock frequency, including

harmonics but excluding d.c.

SPURIOUS FREE DYNAMIC RANGE (SFDR) is the difference, expressed in dB, between the rms values of the

input signal and the peak spurious signal where a spurious signal is any signal present in the output spectrum

that is not present at the input, excluding d.c.

TOTAL HARMONIC DISTORTION (THD) is the ratio, expressed in dB or dBc, of the rms total of the first five

harmonic components at the output to the rms level of the input signal frequency as seen at the output. THD is

calculated as

(2)

first 5 harmonic frequencies. Accurate THD measurement requires a spectrally pure sine wave (monotone) at the

ADC input.

THROUGHPUT TIME is the minimum time required between the start of two successive conversion. It is the

acquisition time plus the conversion and read out times. In the case of the ADC082S101, this is 16 SCLK

periods.

8

Submit Documentation Feedback

Copyright © 2005–2010, Texas Instruments Incorporated

Product Folder Links: ADC082S101