Datasheet

2
1f
2
6f
2
2f
A
A++A ...
10
x log20=THD
ADC161S626
www.ti.com SNAS468C –SEPTEMBER 2008–REVISED MARCH 2013
INTEGRAL NON-LINEARITY (INL) is a measure of the deviation of each individual code from a line drawn from
½ LSB below the first code transition through 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.
MISSING CODES are those output codes that will never appear at the ADC outputs. The ADC161S626 is
ensured not to have any missing codes.
NEGATIVE FULL-SCALE ERROR is the difference between the differential input voltage at which the output
code transitions from code 0x8001h to 0x8000h and −V
REF
+ 1 LSB.
NEGATIVE GAIN ERROR is the difference between the negative full-scale error and the offset error.
OFFSET ERROR is the difference between the differential input voltage at which the output code transitions from
code 0x0000h to 0x0001h and 1 LSB.
POSITIVE FULL-SCALE ERROR is the difference between the differential input voltage at which the output
code transitions from code 0xFFFEh to 0xFFFFh and V
REF
- 1 LSB.
POSITIVE GAIN ERROR is the difference between the positive full-scale error and the offset error.
POWER SUPPLY REJECTION RATIO (PSRR) is a measure of how well a change in the analog supply voltage
is rejected. PSRR is calculated from the ratio of the change in offset error for a given change in supply voltage,
expressed in dB. For the ADC161S626, V
A
is changed from 4.5V to 5.5V.
PSRR = 20 LOG (ΔOutput Offset / ΔV
A
) (3)
SIGNAL TO NOISE RATIO (SNR) is the ratio, expressed in dB, of the rms value of the input signal to the rms
value of the sum of all other spectral components below one-half the sampling frequency, not including
harmonics or d.c.
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 one-half the sampling frequency,
including harmonics but excluding d.c.
SPURIOUS FREE DYNAMIC RANGE (SFDR) is the difference, expressed in dB, between the desired signal
amplitude to the amplitude of the peak spurious spectral component below one-half the sampling frequency,
where a spurious spectral component is any signal present in the output spectrum that is not present at the input
and may or may not be a harmonic.
TOTAL HARMONIC DISTORTION (THD) is the ratio 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, expressed in dB. THD is calculated as
(4)
where A
f1
is the RMS power of the input frequency at the output and A
f2
through A
f6
are the RMS power in the
first 5 harmonic frequencies.
THROUGHPUT TIME is the minimum time required between the start of two successive conversion.
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