MAX1192 datasheet(25/28 Pages) MAXIM

25 / 28 page

Ultra-Low-Power, 22Msps, Dual 8-Bit ADC

______________________________________________________________________________________

Static Parameter Definitions

Integral Nonlinearity (INL)

Integral nonlinearity is the deviation of the values on an

actual transfer function from a straight line. This straight

line can be either a best-straight-line fit or a line drawn

between the end points of the transfer function, once

offset and gain errors have been nullified. The static lin-

earity parameters for the MAX1192 are measured using

the end-point method.

Differential Nonlinearity (DNL)

Differential nonlinearity is the difference between an

actual step width and the ideal value of 1LSB. A DNL

error specification of less than 1LSB guarantees no

missing codes and a monotonic transfer function.

Offset Error

Ideally, the midscale MAX1192 transition occurs at 0.5

LSB above midscale. The offset error is the amount of

deviation between the measured transition point and

the ideal transition point.

Gain Error

Ideally, the full-scale MAX1192 transition occurs at 1.5

LSB below full-scale. The gain error is the amount of

deviation between the measured transition point and

the ideal transition point with the offset error removed.

Dynamic Parameter Definitions

Aperture Jitter

Figure 13 depicts the aperture jitter (tAJ), which is the

sample-to-sample variation in the aperture delay.

Aperture Delay

Aperture delay (tAD) is the time defined between the

rising edge of the sampling clock and the instant when

an actual sample is taken (Figure 13).

Signal-to-Noise Ratio (SNR)

For a waveform perfectly reconstructed from digital

samples, the theoretical maximum SNR is the ratio of

the full-scale analog input (RMS value) to the RMS

quantization error (residual error). The ideal, theoretical

minimum analog-to-digital noise is caused by quantiza-

tion error only and results directly from the ADC’s reso-

lution (N bits):

SNRdB[max] = 6.02

× N + 1.76

In reality, there are other noise sources besides quanti-

zation noise: thermal noise, reference noise, clock jitter,

etc. SNR is computed by taking the ratio of the RMS

signal to the RMS noise. RMS noise includes all spec-

tral components to the Nyquist frequency excluding the

fundamental, the first five harmonics, and the DC offset.

Signal-to-Noise Plus Distortion (SINAD)

SINAD is computed by taking the ratio of the RMS sig-

nal to the RMS noise. RMS noise includes all spectral

components to the Nyquist frequency excluding the

the fundamental and the DC offset.

Effective Number of Bits (ENOB)

ENOB specifies the dynamic performance of an ADC at

a specific input frequency and sampling rate. An ideal

ADC’s error consists of quantization noise only. ENOB

for a full-scale sinusoidal input waveform is computed

from:

ENOB

SINAD

-1 76

602

HOLD

ANALOG

INPUT

SAMPLED

DATA (T/H)

T/H

tAD

tAJ

TRACK

CLK

Figure 13. T/H Aperture Timing

MAX1192 Datasheet(PDF) 25 Page - Maxim Integrated Products

MAX1192 Datasheet(HTML) 25 Page - Maxim Integrated Products

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