BU1S12S1AG-LB Datasheet, PDF (6/20 Pages) Rohm – Successive Approximation A/D Converter

BU1S12S1AG-LB
Term Definitions
ACQUISITION TIME:
At the 13th rising edge of SCLK, the mode is changed from Hold mode to Track mode and the sampling capacitor starts
to be charged by the analog input voltage. This charge time is defined as the acquisition time.
APERTURE DELAY:
It is defined as the time from falling edge of CSB to the time when the analog input voltage is acquired.
APERTURE JITTER:
The variation in the aperture delays in sampling operations. Aperture jitter gets to affect signal-to-noise ratio.
INTEGRAL NON-LINEARLITY (INL):
It is a measure of the deviation of each individual code from a line drawn from zero scale (0.5 LSB below the first code
transition) through full scale (0.5 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.
DIFFERENTIAL NON-LINEARLITY (DNL):
It is the measure of the maximum deviation from the ideal step size of 1 LSB.
OFFSET ERROR (OE):
It is the deviation of the first code transition “(000…000) to (000…001)” from the ideal of 0.5 LSB.
FULL SCALE ERROR (FSE):
It is the deviation of the last code transition “(111…110) to (111…111)” from the ideal of “VA – 1.5LSB.”
GAIN ERROR (GE):
It is defined as full scale error minus offset error.
TOTAL HARMONIC DISTORTION (THD):
It 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
where Af1 is the RMS power of the input frequency at the output and Af2 through Af6 are the RMS power in the first 5
harmonic frequencies.
SIGNAL TO NOISE AND DISTORTION RATIO(SINAD):
It 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 sampling frequency, including harmonics but excluding d.c.
EFFECTIVE NUMBER OF BITS(ENOB):
It is another method of specifying Signal-to-Noise and Distortion or SINAD. ENOB is defined as “(SINAD – 1.76) / 6.02”
and says that the converter is equivalent to a perfect ADC of this (ENOB) number of bits.
SIGNAL TO NOISE RATIO (SNR):
It 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 half the sampling frequency, not including harmonics.
SPURIOUS FREE DYNAMIC RANGE (SFDR):
It is the difference, expressed in dB, between the desired signal amplitude to the amplitude of the peak spurious spectral
component, where a spurious spectral component is any signal present in the output spectrum that is not present at the
input and may be a harmonic.
CONVERSION TIME:
It is the required time for the A/D converter to convert the sampled analog input signal to the digital code.
THROUGHPUT PERIOD:
It is the period that should be used as an interval time between any adjacent conversions.
www.rohm.com
© 2016 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
6/16
TSZ02201-0GSG0GZ10180-1-2
04.Jul.2016 Rev.001