Datasheet

t
CSH
SCLK
CS
t
CSS
CS
t
CONVERT
t
ACQ
t
CH
t
CL
t
DACC
t
EN
t
DH
t
DS
FOUR ZEROS
DB10
DONTC DONTC ADD2 ADD1 ADD0
DONTC
DONTC DONTC
DB11
DB9 DB8
DB1
1687654321
DB0
DIN
DOUT
SCLK
CS
t
DIS
t
DHLD
ADC128S052
www.ti.com SNAS333D –AUGUST 2005–REVISED MARCH 2013
Figure 2. ADC128S052 Serial Timing Diagram
Figure 3. SCLK and CS Timing Parameters
Specification Definitions
ACQUISITION TIMEis the time required for the ADC to acquire the input voltage. During this time, the hold
capacitor is charged by the input voltage.
APERTURE DELAYis the time between the fourth falling edge of SCLK and the time when the input signal is
internally acquired or held for conversion.
CONVERSION TIME is the time required, after the input voltage is acquired, for the ADC to convert the input
voltage to a digital word.
CHANNEL-TO-CHANNEL ISOLATION is resistance to coupling of energy from one channel into another
channel.
CROSSTALK is the coupling of energy from one channel into another channel. This is similar to Channel-to-
Channel Isolation, except for the sign of the data.
DIFFERENTIAL NON-LINEARITY (DNL) is the measure of the maximum deviation from the ideal step size of 1
LSB.
DUTY CYCLEis the ratio of the time that a repetitive digital waveform is high to the total time of one period. The
specification here refers to the SCLK.
EFFECTIVE NUMBER OF BITS (ENOB, or EFFECTIVE BITS) 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.
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
V
REF
+
and is defined as:
V
FSE
= V
max
+ 1.5 LSB – V
REF
+
• where V
max
is the voltage at which the transition to the maximum code occurs. FSE can be expressed
in Volts, LSB or percent of full scale range. (1)
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