CS5317 datasheet(26/32 Pages) CIRRUS

26 / 32 page

GENERAL DESCRIPTION

The CDB5317 Evaluation Board is a stand-alone

environment for easy lab evaluation of the

CS5317 Delta-Sigma Analog-to-Digital Converter.

Included on the board is a serial-to-parallel con-

verter. The user can access output data in either

parallel or serial form. When supplied with the

necessary +5 V and -5 V power supplies, a

CLKIN signal, and an analog signal source, the

CDB5317 will provide converted data at the 40

pin header.

SUGGESTED EVALUATION METHOD

An efficient evaluation of the CS5317 using the

CDB5317 may be accomplished as described be-

low.

The following equipment will be required for the

evaluation:

• The CDB5317 Evaluation Board.

• A power supply capable of supplying +5V and

-5V.

• A clock source as the CLKIN signal of the

CS5317.

• A spectrally pure sine wave generator such as

the Krohn-Hite Model 4400A "Ultra-Low Distor-

tion Oscillator".

• A PC equipped with a digital data acquisition

board such as the Metrabyte Model PIO12 "24 Bit

Parallel Digital I/O Interface".

• A software routine to collect the data and per-

form a Fast Fourier Transform (FFT).

The evaluation board includes filter components

for the on-chip phase locked loop. The compo-

nents are adequate for testing if the CLKIN signal

has little or no phase-jitter. If the CDB5317 board

is being tested as part of a system which generates

a CLKIN which contains jitter, the PLL filter

components may need to be optimized for your

system (see the CS5317 data sheet).

Set-up for evaluation is straightforward. First de-

cide the operating mode and place the jumper on

the board for the proper selection. Then decide

whether the filter components for the phase

locked loop are adequate or whether they should

be changed for your evaluation. The PLL will

lock on a steady clock input with the filter as it is.

Connect the necessary 5 V (CMOS compatible)

CLKIN signal for the application. Use the sine-

wave generator to supply the analog signal to the

CDB5317. Apply the analog input and CLKIN

signals only when the evaluation board is pow-

ered up. Converted data will then appear at the

header on the CDB5317. The header should be

connected to the digital data acquisition board in

the PC through an IDC 40 pin connector and ca-

ble. The software routine should collect the data

from the CDB5317 and run a standard 1024 point

Fast Fourier Transform (FFT). Such an analysis

results in a plot similar to Figure 1. This plot re-

sulted from using a 1kHz input signal and a

Blackman-Harris window for the FFT.

The signal to noise and signal to total harmonic

distortion characteristics of the CS5317 may be

easily measured in this way. The signal to total

harmonic distortion value for a particular input is

the ratio of the RMS value of the input signal and

the sum of the RMS values of the harmonics

shown in the diagram. The dynamic range of the

CS5317 can be measured by reducing the input

Figure 1. FFT Plot Example

Signal

Amplitude

Relative to

Full Scale

Input Frequency

0dB

-20dB

-40dB

-60dB

-80dB

-100dB

-120dB

9.6 kHz

1 kHz

Sampling Rate: 19.2 kHz

Full Scale:

S/(N+D): 81.39 dB

± 2.75 V

CDB5317

DS27DB3

CS5317 Datasheet(PDF) 26 Page - Cirrus Logic

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