Cirrus Logic CDB4344 User Manual

Evaluation Board for CS4344

CDB4344

Features

z Demonstrates recommended layout and

grounding arrangements

z CS8416 receives S/PDIF, & EIAJ-340

compatible digital audio

z Header for external PCM audio
z Requires only a digital signal source and

power supplies for a complete Digital-to­Analog-Converter system

Description

The CDB4344 evaluation board is an excellent means
for quickly evaluating the CS4344 24-bit, 10 pin stereo
D/A converter. Evaluation requires an analog signal an­alyzer, a digital signal source, and a power supply.
Analog line level outputs are provided via RCA phono
jacks.

The CS8416 digital audio receiver I.C. provides the sys­tem timing necessary to operate the Digital-to-Analog
converter and will accept S/PDIF, and EIAJ-340-compat­ible audio data. The evaluation board may also be
configured to accept external timing and data signals for
operation in a user application during system
development.

ORDERING INFORMATION

CDB4344 Evaluation Board

Inputs for Clocks

and Data

CS8416

Digital Audio

Interface

CS4344

Analog Outputs

http://www.cirrus.com

Copyright © Cirrus Logic, Inc. 2004

(All Rights Reserved)

June ‘04

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TABLE OF CONTENTS

1. CS4344 DIGITAL TO ANALOG CONVERTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2. CS8416 DIGITAL AUDIO RECEIVER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3. INPUT FOR CLOCKS AND DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

4. POWER SUPPLY CIRCUITRY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

5. GROUNDING AND POWER SUPPLY DECOUPLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

6. ANALOG OUTPUT FILTERING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

7. ERRATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

LIST OF FIGURES

Figure 1. System Block Diagram and Signal Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Figure 2. CS4344 and outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

CDB4344

Figure 3. CS8416 S/PDIF Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Figure 4. PCM Input Header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Figure 5. Power Supply Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Figure 6. Silkscreen Top. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Figure 7. Top Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Figure 8. Bottom Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

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CDB4344

CDB4344 SYSTEM OVERVIEW

The CDB4344 evaluation board is an excellent means of quickly evaluating the CS4344. The
CS8416 digital audio interface receiver provides an easy interface to digital audio signal sources
including the majority of digital audio test equipment. The evaluation board also allows the user
to supply external PCM clocks and data through a header for system development.

The CDB4344 schematic has been partitioned into 4 schematics shown in Figures 2 through 5.
Each partitioned schematic is represented in the system diagram shown in Figure 1. Notice that
the system diagram also includes the interconnections between the partitioned schematics.

1. CS4344 DIGITAL TO ANALOG CONVERTER

A description of the CS4344 is included in the CS4344 datasheet.

2. CS8416 DIGITAL AUDIO RECEIVER

The system receives and decodes the standard S/PDIF data format using a CS8416 Digital Au­dio Receiver, Figure 3. The outputs of the CS8416 include a serial bit clock, serial data, left-right
clock, and a 128/256 Fs master clock. The CS8416 data format is fixed to I2S (can be changed
with R42 and R47). The operation of the CS8416 and a discussion of the digital audio interface
is included in the CS8416 datasheet.

The evaluation board has been designed such that the input can be either optical or coax, see
Figure 3. However, both inputs cannot be driven simultaneously.

The right hand switch of S2 sets the output MCLK to LRCK ratio of the CS8416. This switch
should be set to 256 (closed) for inputs Fs<=96 kHz and 128 (open) for Fs>=64 kHz. The 8416
must be manually reset using RX_RST (S1) when this switch is changed.

3. INPUT FOR CLOCKS AND DATA

The evaluation board has been designed to allow interfacing to external systems via the header
J9. Header J9 allows the evaluation board to accept externally generated PCM clocks and data.
The schematic for the clock/data input is shown in Figure 4. The left hand switch of S2 selects
the source as either CS8416 (closed) or header J9 (open).

Please see the CS4344 datasheet for more information.

4. POWER SUPPLY CIRCUITRY

Power is supplied to the evaluation board by three binding posts (GND, +5V, and ‘+3.3V to +5V’),
see Figure 5. The ‘+3.3V to +5V’ which supplies VA can be jumpered to a +3.3 V regulator or the
+5V binding post. The VA supply should be set to the recommended values stated in the CS4344
datasheet.

WARNING: Refer to the CS4344 datasheet for maximum allowable voltages levels. Operation
outside of this range can cause permanent damage to the device.

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CDB4344

5. GROUNDING AND POWER SUPPLY DECOUPLING

As with any high performance converter, the CS4344 requires careful attention to power supply
and grounding arrangements to optimize performance. Figure 2 details the connections to the
CS4344 and Figures 6, 7, and 8 show the component placement and top and bottom layout. The
decoupling capacitors are located as close to the CS4344 as possible. Extensive use of ground
plane fill in the evaluation board yields large reductions in radiated noise.

6. ANALOG OUTPUT FILTERING

The analog output on the CDB4344 has been designed according to the CS4344 datasheet. This
output circuit includes an AC coupling cap and a single pole R and C. An additional load resis­tance may be added by stuffing R10 and R26 to test the CS4344’s load driving capability.

CONNECTOR INPUT/OUTPUT SIGNAL PRESENT

+5V Input + 5 V power

GND Input Ground connection from power supply

+3.3V to +5V Input +3.3 V to +5 V positive supply for the CS4344 VA power

S/PDIF INPUT - J5 Input Digital audio interface input via coax

S/PDIF INPUT - OPT1 Input Digital audio interface input via optical

PCM INPUT - J9 Input Input for master, serial, left/right clocks and serial data

LEFT_OUT and

RIGHT_OUT

Output RCA line level analog outputs

Table 1. System Connections

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CDB4344

JUMPER /

SWITCH PURPOSE POSITION FUNCTION SELECTED

J4 Selects source of voltage

for the CS4344 VA supply

J7 Provides contact points to

measure current

S1 Resets CS8416 The CS8416 must be reset if switch S2 is

S2 Sets clock source left

Sets MCLK ratio of CS8416 right

Table 2. CDB4344 Jumper Settings

*Default Factory Settings.

VA

+3.3V

*+5V

- Measure voltage across these nodes and divide

Voltage source is the +3.3V to +5V binding post

Voltage source is a +3.3V regulator

Voltage source is +5V binding post

result by 10 to get current in Amps

changed

Sets clock source for CS4344 (open=J9, *closed

= CS8416)

Selects 128x (open) or 256x (*closed)

MCLK/LRCK ratio output for CS8416

7. ERRATA

CDB4344 Revision B.0

Switch S2 is oriented incorrectly on some boards (if open is away from binding posts) and thus
the 0 and 1 labels above and below are incorrect. Using closed for 0 and open for 1, the table
next to the switch will be correct.

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