AD9040A

REV. B

–5–

DEFINITIONS OF SPECIFICATIONS

Analog Bandwidth

The analog input frequency at which the spectral power of the

fundamental frequency (as determined by FFT analysis) is

reduced by 3 dB.

Aperture Delay

The delay between 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 Gain

The percentage of amplitude change of a small high frequency

sine wave (3.58 MHz) superimposed on a low frequency signal

(15.734 kHz).

Differential Nonlinearity

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

Differential Phase

The phase change of a small high frequency sine wave (3.58 MHz)

superimposed on a low frequency signal (15.734 kHz).

Harmonic Distortion

The rms value of the fundamental divided by the rms value of

the harmonic.

Integral Nonlinearity

The deviation of the transfer function from a reference line

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

termined by a least square curve fit.

Minimum Conversion Rate

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

frequency tested drops by no more than 3 dB below the guaran-

teed limit.

Maximum Conversion Rate

The encode rate at which parametric testing is performed.

Output Propagation Delay

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

ENCODE command and the 1 V/4 V points of output data.

Overvoltage Recovery Time

The amount of time required for the converter to recover to

10-bit accuracy after an analog input signal 150% of full scale is

reduced to the full-scale range of the converter.

Power Supply Rejection Ratio (PSRR)

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

power supply voltage.

Signal-to-Noise Ratio (SNR)

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

“noise,” which is defined as the sum of all other spectral com-

ponents, including harmonics but excluding dc, with an analog

input signal 1 dB below full scale.

Signal-to-Noise Ratio (Without Harmonics)

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

“noise,” which is defined as the sum of all other spectral com-

ponents, excluding the first eight harmonics and dc, with an

analog input signal 1 dB below full scale.

Transient Response

The time required for the converter to achieve 10-bit accuracy

when a step function is applied to the analog input.

Two-Tone Intermodulation Distortion (IMD) Rejection

The ratio of the power of either of two input signals to the

power of the strongest third-order IMD signal.

2k

1k

1mA

1mA

1k

ANALOG INPUT

GND

6.8k

2.5k

REFERENCE CIRCUIT

GND

BANDGAP OUTPUT

GND

D0-9

CMOS OUTPUT

1k

1k

Figure 2. Equivalent Circuits