AD9433 datasheet(15/21 Pages) AD

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AD9433

Rev. A | Page 14 of 20

TERMINOLOGY

Analog Bandwidth

The analog input frequency at which the spectral power of the

fundamental frequency (as determined by the FFT analysis) is

reduced by 3 dB.

Aperture Delay

The delay between the 50% point of the rising edge of the

ENCODE command and the instant at which the analog input

is sampled.

Aperture Uncertainty (Jitter)

The sample-to-sample variation in aperture delay.

Differential Analog Input Resistance, Differential Analog

Input Capacitance, and Differential Analog Input Impedance

The real and complex impedances measured at each analog

input port. The resistance is measured statically and the

capacitance and differential input impedances are measured

with a network analyzer.

Differential Analog Input Voltage Range

The peak-to-peak differential voltage that must be applied to

the converter to generate a full-scale response. Peak differential

voltage is computed by observing the voltage on a single pin

and subtracting the voltage from the other pin, which is 180°

out of phase. Peak-to-peak differential voltage is computed by

rotating the input phase 180° and taking the peak measure-

ment again. The difference is then computed between both

peak measurements.

Differential Nonlinearity (DNL)

The deviation of any code width from an ideal 1 LSB step.

Effective Number of Bits (ENOB)

The effective number of bits (ENOB) is calculated from the

measured SNR based on the following equation:

⎠

⎝

ENOB

log

⎟

⎞

⎜

⎛

−

Amplitude

Input

Amplitude

Scale

Full

SNR

MEASURED

Encode Pulse Width/Duty Cycle

Pulse width high is the minimum amount of time that the

encode pulse should be left in the Logic 1 state to achieve the

rated performance. Pulse width low is the minimum amount

of time that the encode pulse should be left in the Logic 0 state.

At a given clock rate, these specifications define an acceptable

encode duty cycle.

Full-Scale Input Power

Expressed in dBm. Computed using the following equation:

Gain Error

The difference between the measured and the ideal full-scale

input voltage range of the ADC.

Harmonic Distortion

The ratio of the rms signal amplitude fundamental frequency

to the rms signal amplitude of a single harmonic component

(second, third, and so on); reported in dBc.

Integral Nonlinearity (INL)

The deviation of the transfer function from a reference line

measured in fractions of 1 LSB using a “best straight line”

determined by a least square curve fit.

Maximum Conversion Rate

The maximum encode rate at which parametric testing is

performed.

Minimum Conversion Rate

The encode rate at which the SNR of the lowest analog signal

frequency drops by no more than 3 dB below the guaranteed

limit.

Noise (for Any Range within the ADC)

Noise can be calculated using the following equation:

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

−

0.001

dBFS

dBc

dBm

NOISE

Signal

SNR

where:

is the input impedance.

is the full scale of the device for the frequency in question.

SNR

is the value for the particular input level.

Signal

is the signal level within the ADC reported in dB below

full scale. This value includes both thermal and quantization

noise.

Output Propagation Delay

The delay between a differential crossing of ENCODE and

ENCODE and the time when all output data bits are within

valid logic levels.

Power Supply Rejection Ratio (PSRR)

The ratio of a change in input offset voltage to a change in

power supply voltage.

Signal-to-Noise and Distortion (SINAD)

The ratio of the rms signal amplitude (set at 1 dB below full

scale) to the rms value of the sum of all other spectral compo-

nents, including harmonics but excluding dc.

Signal-to-Noise Ratio (SNR)

The ratio of the rms signal amplitude (set at 1 dB below full

scale) to the rms value of the sum of all other spectral com-

ponents, excluding the first five harmonics and dc.

⎟

⎠

⎜

⎝

001

⎟

⎞

⎜

⎛

log

FullScale

Power

rms

FullScale

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