SNAS333E August 2005 – December 2015 ADC128S052 , ADC128S052-Q1
PRODUCTION DATA.
11 Device and Documentation Support
11.1 Device Support
11.1.1 Device Nomenclature
11.1.1.1 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 VREF+ and is defined as:
- where Vmax 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.
Equation 7. VFSE = Vmax + 1.5 LSB – VREF+
where
-
GAIN ERRORis the deviation of the last code transition (111...110) to (111...111) from the ideal (VREF - 1.5 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 an individual ADC input at the same time. It is defined as the ratio of the power in both the second or the third order intermodulation products to the power in one of the original frequencies. Second order products are fa ± fb, where fa and fb are the two sine wave input frequencies. Third order products are (2fa ± fb ) and (fa ± 2fb). IMD is usually expressed in dB.
-
MISSING CODESare those output codes that never appear sat the ADC outputs. These codes cannot be reached with any input value. The ADC128S052 is ensured not to have any missing codes.
-
OFFSET ERRORis the deviation of the first code transition (000...000) to (000...001) from the ideal (that is, GND + 0.5 LSB).
-
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 d.c. or the harmonics included in THD.
-
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 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 or may not be a harmonic.
-
TOTAL HARMONIC DISTORTION (THD) is the ratio, expressed in 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.
Equation 8. 
where
-
THROUGHPUT TIME is the minimum time required between the start of two successive conversions. It is the acquisition time plus the conversion and read out times. In the case of the ADC128S052, this is 16 SCLK periods.
11.2 Related Links
The table below lists quick access links. Categories include technical documents, support and community resources, tools and software, and quick access to sample or buy.
Table 4. Related Links
| PARTS | PRODUCT FOLDER | SAMPLE & BUY | TECHNICAL DOCUMENTS | TOOLS & SOFTWARE | SUPPORT & COMMUNITY |
|---|---|---|---|---|---|
| ADC128S052 | Click here | Click here | Click here | Click here | Click here |
| ADC128S052-Q1 | Click here | Click here | Click here | Click here | Click here |
11.3 Community Resources
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use.
-
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers.
-
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support.
11.4 Trademarks
E2E is a trademark of Texas Instruments.
SPI, QSPI are trademarks of Motorola.
All other trademarks are the property of their respective owners.
11.5 Electrostatic Discharge Caution
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.
11.6 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.