AD9835 datasheet(12/28 Pages) AD

12 / 28 page

AD9835

Data Sheet

Rev. A | Page 12 of 28

TERMINOLOGY

Integral Nonlinearity

This is the maximum deviation of any code from a straight line

passing through the endpoints of the transfer function. The

endpoints of the transfer function are zero scale, a point 0.5 LSB

below the first code transition (000 . . . 00 to 000 . . . 01) and full

scale, a point 0.5 LSB above the last code transition (111 . . . 10

to 111 . . . 11). The error is expressed in LSBs.

Differential Nonlinearity

This is the difference between the measured and ideal 1 LSB

change between two adjacent codes in the DAC.

Signal to (Noise + Distortion)

Signal to (Noise + Distortion) is measured signal to noise at

the output of the DAC. The signal is the rms magnitude of the

fundamental. Noise is the rms sum of all the non-fundamental

signals up to half the sampling frequency (fMCLK/2) but excluding

the dc component. Signal to (Noise + Distortion) is dependent

on the number of quantization levels used in the digitization

process; the more levels, the smaller the quantization noise. The

theoretical Signal to (Noise + Distortion) ratio for a sine wave

input is given by

Signal to (Noise + Distortion) = (6.02N + 1.76) dB

where N is the number of bits. Thus, for an ideal 10-bit converter,

Signal to (Noise + Distortion) = 61.96 dB.

Total Harmonic Distortion

Total Harmonic Distortion (THD) is the ratio of the rms sum of

harmonics to the rms value of the fundamental. For the AD9835,

THD is defined as

(

)

log

THD

where V1 is the rms amplitude of the fundamental and V2, V3,

V4, V5, and V6 are the rms amplitudes of the second through the

sixth harmonic.

Output Compliance

The output compliance refers to the maximum voltage that

can be generated at the output of the DAC to meet the specifica-

tions. When voltages greater than that specified for the output

compliance are generated, the AD9835 may not meet the

specifications listed in the data sheet.

Spurious Free Dynamic Range

Along with the frequency of interest, harmonics of the funda-

mental frequency and images of the MCLK frequency are

present at the output of a DDS device. The spurious free dynamic

range (SFDR) refers to the largest spur or harmonic present in

the band of interest. The wideband SFDR gives the magnitude

of the largest harmonic or spur relative to the magnitude of the

fundamental frequency in the bandwidth ±2 MHz about the

fundamental frequency. The narrow band SFDR gives the

attenuation of the largest spur or harmonic in a bandwidth

of ±50 kHz about the fundamental frequency.

Clock Feedthrough

There will be feedthrough from the MCLK input to the analog

output. Clock feedthrough refers to the magnitude of the MCLK

signal relative to the fundamental frequency in the AD9835’s

output spectrum.

AD9835 Datasheet(PDF) 12 Page - Analog Devices

AD9835 Datasheet(HTML) 12 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Datasheet Download

Link URL