PRELIMINARY TECHNICAL DATA

AD9430

-10-

4/01/2002 REV. PrG

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.

Crosstalk

Coupling onto one channel being driven by a low level (–40

dBFS) signal when the adjacent interfering channel is driven

by a full-scale signal.

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 degrees out of phase. Peak-to-peak differential

is computed by rotating the inputs phase 180 degrees and

again taking the peak measurement. The difference is then

computed between both peak measurements.

Differential Nonlinearity

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

Effective Number of Bits

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

measured SNR based on the equation:

02

.

6

76

.

1

dB

SNR

ENOB

=

ENCODE Pulsewidth / Duty Cycle

Pulsewidth high is the minimum amount of time that the

ENCODE pulse should be left in Logic 1 state to achieve

rated performance; pulsewidth low is the minimum time

ENCODE pulse should be left in low state. See timing

these specifica-tions define an acceptable ENCODE duty

cycle.

Full-Scale Input Power

Expressed in dBm. Computed using the following equation:





























=

001

.

log

10

2

Input

Fullscale

Fullscale

Z

V

Power

rms

Gain Error

Gain error is the difference between the measured and ideal

full scale input voltage range of the ADC.

Harmonic Distortion, Second

The ratio of the rms signal amplitude to the rms value of the

second harmonic component, repo rted in dBc.

Harmonic Distortion, Third

The ratio of the rms signal amplitude to the rms value of the

third harmonic component, reported in dBc.

Integral Nonlinearity

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.

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.

Maximum Conversion Rate

The encode rate at which parametric testing is performed.

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.

Noise (for Any Range within the ADC)













−

−

=

10

10

*

001

.

*

dBFS

dBc

dBm

Signal

SNR

FS

noise

Z

V

Where Z is the input impedance, FS is the full scale of the

device for the frequency in question, SNR is the value for the

particular input level, and Signal is the signal level within

the ADC reported in dB below full scale. This value includes

both thermal and quantization noise.

Power Supply Rejection Ratio

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 1 dB below full

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

components, including harmonics but excluding dc.