Cirrus Logic CRD4299-1 AVR User Manual
CRD4299-1 AMR
CrystalClear™ AC '97 AMR Reference Design
Features
l AMR Audio Codec add-in card designed to
meet the Intel® Audio/Modem Riser
Specification
l High quality, low cost, 2-layer, single sided
adapter board
l CS4299 Sound Fusion
l Complete suite of Analog and Digital I/O
connections:
- Line In, Line Out, Mic In, Modem Audio
connection, CD Audio In, Video In, Aux In,
Headphone Out and Optical Digital Out
l Meets or exceeds Microsoft’ s PC 97, PC 98,
and PC 99, both required and advanced,
audio performance requirements.
®
Audio Codec ’97
Description
The CRD4299-1 AMR add-in board reference design
showcases Cirrus Logic’s Crystal Audio AC ’97 CS4299
SoundFusion, and is Audio/Modem Riser Specification[2], compliant. The CRD4299-1 AMR card is 2.7"
high by 3.6" long.
The CRD4299-1 AMR reference de sign inc ludes a customer ready manufac turing kit. Include d in the kit are a
full set of schematic desi gn files (OrCAD
PCB job files (PADS
(Gerber) , bracket drawings, and bill of materials. The
design is production ready as is, or can be easily
modified to incorporate specific OEM changes. Documentation source files are available to assist the OEM to
quickly provide an accurate end user manual.
ORDERING INFO CRD4299-1 AMR
®
ASCII), PCB artwork files
®
7.2 format),
Preliminary Product Information
P.O. Box 17847, Austin, Texas 78760
(512) 445 7222 FAX: (512) 445 7581
http://www.cirrus.com
CS4299
This document contains information for a new product.
Cirrus Logic reserves the right to modify this product without notice.
Copyright Cirrus Logic, Inc. 1999
(All Rights Reserved)
OCT ‘99
DS319RD1A1
1
TABLE OF CONTENTS
1. GENERAL INFORMATION ............................................................................ 4
2. REFERENCE DESIGN FEATURES ............................................................... 4
2.1 Digital Audio Out .................................................................................. 4
2.2 CS4299 Audio Codec ‘97 ....................................................................4
2.2.1 Power Requirements .................................................................. 5
2.3 Analog I/O ............................................................................................ 5
2.4 Audio I/O .............................................................................................. 5
2.4.1 Line Out ......................................................................................5
2.4.2 Headphone Out .......................................................................... 5
2.4.3 Line In ........................................................................................ 5
2.4.4 Mic In ..........................................................................................5
2.4.5 CD Audio In ................................................................................ 6
2.4.6 Aux In ......................................................................................... 6
2.4.7 Video In ...................................................................................... 6
2.4.8 Modem Audio Connection ..........................................................6
3. SCHEMATIC DESCRIPTION ......................................................................... 7
3.1 Figure 11: Block Diagram ....................................................................7
3.2 Figure 12: AMR Bus Interface ............................................................. 7
3.3 Figure 13: Power Supply ..................................................................... 7
3.4 Figure 14: CS4299 AC ‘97 Audio Codec ............................................. 7
3.5 Figure 15: Analog Inputs ...................................................................... 7
3.6 Figure 16: Audio Outputs ..................................................................... 8
3.7 Figure 17: Microphone Pre-amp and Bias ...........................................8
3.8 Component Selection .......................................................................... 8
3.9 EMC Components ...............................................................................8
4. GROUNDING AND LAYOUT ......................................................................... 9
4.1 Partitioned Voltage and Ground Planes .............................................. 9
4.2 CS4299 Layout Notes .......................................................................... 9
5. AUDIO PERFORMANCE EVALUATION .....................................................10
5.1 Plots ................................................................................................... 10
6. REFERENCES ..............................................................................................17
7. ADDENDUM ................................................................................................. 17
8. BILL OF MATERIALS .................................................................................. 25
CRD4299-1 AMR
Contacting Cirrus Logic Support
For a complete listing of Direct Sales, Distributor, and Sales Representative contacts, visit the Cirrus Logic web site at:
http://www.cirrus.com/corporate/contacts/
CrystalClear is a trademark of Cirrus Logic, Inc.
Intel is a registered trademark of Intel Corporation.
OrCAD is a registered trademark of OrCAD, Inc.
SoundFusion is a registered trademark of Cirrus Logic, Inc.
Preliminary product inf o rmation describes products whi ch are i n p r od ucti on, b ut for which full characteriza t ion data is not yet available. Advance product information describes products which are in development and subject to development changes. Cirrus Logic, Inc. has made best efforts to ensure that the information
contained in this document i s accurat e and reli able. However , t he infor mation is subje ct to chang e without noti ce and is provi d ed “AS IS” without warrant y of
any kind (express or implied). No responsibility is assumed by Cirrus Logic, Inc. for the use of this information, nor for infringements of patents or other ri g ht s
of third parties. This document is the pro perty of Cirrus Logi c, Inc. and i mplie s no licen se under patents, copyrights, tr ademarks, or trade secre ts. No part of
this publication may be copied, reproduced , stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photographic, or
otherwise) without the pr i or writ ten consent of Cirrus Logic, Inc. Ite ms f rom any Ci rrus L ogi c websi t e or disk may be printed for use by the user. However, no
part of the printout or electronic files may be copied, reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical,
photographic, or otherwise) without the prior written consent of Cirrus Logic, Inc.Furthermore, no part of this publication may be used as a basis for manufacture
or sale of any items without the prior written consent of Cirrus Logic, Inc. The names of products of Cirrus Logic, Inc. or other vendors and suppliers appearing
in this document may be trademarks or service marks of their respective owners which may be registered in some jurisdictions. A list of Cirrus Logic, Inc. trademarks and service marks can be found at http://www.cirrus.com.
2 DS319RD1A1
LIST OF FIGURES
Figure 1. Full Duplex (A-D-PC-D-A): Line In/Out Frequency Response ..................................... 10
Figure 2. Full Duplex (A-D-PC-D-A): Line In/Out Dynamic Range .............................................. 10
Figure 3. Full Duplex (A-D-PC-D-A): Line In/Out THD+N vs. Frequency ................................... 11
Figure 4. Analog Mixer (A-A): Line In/Out Frequency Response ................................................ 11
Figure 5. Analog Mixer (A-A): Line In/Out Dynamic Range ........................................................ 12
Figure 6. Analog Mixer (A-A): Line In/Out THD+N vs. Frequency .............................................. 12
Figure 7. Analog Mixer (A-A): Mic In/Line Out Frequency Response ......................................... 13
Figure 8. Analog Mixer (A-A): Mic In/Line Out Dynamic Range .................................................. 13
Figure 9. Analog Mixer (A-A): Mic In/Line Out THD+N vs. Frequency ........................................ 14
Figure 10. Analog Mixer (A-A): Line In/Out Crosstalk vs. Frequency ......................................... 14
Figure 11. Block Diagram ............................................................................................................. 16
Figure 12. AMR Bus ..................................................................................................................... 17
Figure 13. Power Supplies ........................................................................................................... 18
Figure 14. CS4299 ....................................................................................................................... 19
Figure 15. Audio In ....................................................................................................................... 20
Figure 16. Audio Out .................................................................................................................... 21
Figure 17. Mic Pre-Amp ............................................................................................................... 22
Figure 18. Assembly Drawing ...................................................................................................... 23
Figure 19. Top Layer .................................................................................................................... 24
Figure 20. Bottom Layer ............................................................................................................... 25
Figure 21. Bracket Drawing .......................................................................................................... 26
CRD4299-1 AMR
LIST OF TABLES
Table 1. Reference Designators ..................................................................................................... 9
Table 2. Microphone Support Specifications................................................................................... 9
Table 3. Full Duplex Specifications................................................................................................. 9
Table 4. Analog Mixer, Line In to Line Out Specifications............................................................... 9
Table 5. Analog Mixer, Mic In to Line Out Specifications................................................................ 9
DS319RD1A1 3
CRD4299-1 AMR
1. GENERAL INFORMATION
The CRD4299-1 AMR is a production-grade
AMR audio card reference design using the
CS4299 SoundFusion Audio Codec ‘97. The design supports the functionally compatible CS4299,
CS4297A, or CS4297 AC ‘97 SoundFusion Audio
Codecs.
The AMR board advantage lies in the complete
separation of the analog section from the noisy digital environment of a personal computer. A 5-wire
digital link is all that is required to connect the audio codec to the PCI bus-based AC ‘97 controller.
This allows the audio section to reach the required
dynamic range of ~90 dB FS A while making the
layout and placement of the audio section easier to
implement. The CS4299 performs the Digital-toAnalog Conversion (DAC) for the digital audio
output stream and also provides multiple analog
audio inputs and outputs, analog mixing and Analog-to-Digital Conversion (ADC).
dec. Digital out is provided through a Toshiba
TOTX173 optical TOS-LINK jack on the board
edge. There are many advantages in using a fiber
optic link versus the traditional coaxial link. Fiber
optic is a non-metallic insulator thereby preventing
ground loops and electromagnetic interference.
For signal transmission, it offers low attenuation,
high bandwidth, low propagation delay, low bit error rates, small size, and cost efficiency. The signal
is IEC 958 and CP-1201 compliant.
2.2 CS4299 Audio Codec ‘97
The CS4299 is a mixed-signal serial Codec based
on the AC ‘97 specification revision 2.1 [1]. It is
designed to be paired with a digital controller, located on the PCI bus. The AC ‘97 Controller is responsible for all communications between the
CS4299 and the rest of the system. The CS4299
functions as an analog mixer, a stereo ADC, a stereo DAC, and a control and digital audio stream interface to the AC ‘97 controller.
This card is designed to provide the highest possible functionality, along with industry leading audio
performance at a low manufacturing cost. Care was
taken with component placement and signal routing to minimize sources that can degrade audio performance. Cirrus’ analog design know-how has
resulted in a board that preserves the exceptional
analog performance of the CS4299.
2. REFERENCE DESIGN FEATURES
The CRD4299-1 AMR reference design illustrates
a high quality, low cost two-layer add-in card layout. The card is sectioned i nto three main part s: the
AMR bus section, the CS4299 Audio Codec ‘97
section, and the Analog I/O section.
2.1 Digital Audio Out
The AMR bus provides digital out in a format compatible with the consumer portion of IEC 958. An
older version of this standard is also known as
S/PDIF. Depending upon the codec, the SPDIF signal originates either from the AMR bus or the co-
The CS4299 contains two distinct functional sections: digital and analog. The digital section includes the AC-link registers, power management
support, SYNC detection circuitry, AC-link serial
port interface logic, and the 24.576 MHz crystal
master clock. The analog section includes the analog input multiplexer (mux), stereo input mixer,
stereo output mixer, mono output mixer, stereo
ADC, stereo DAC, and analog volume controls.
For more information refer to the CS4299
Datasheet [3]. The capacitors required for the
CS4299 and their placement are discussed in the
CS4299 Datasheet [3]. Refer to the Grounding and
Layout section of the data sheet for the recommended routing of the audio section.
2.2.1 Power Requirements
The CS4299 requires both a digital +3.3 V and an
analog +5 V supply. The digital power is supplied
from the AMR bus. A voltage regulator is recommended for the analog supply. A Motorola
4 DS319RD1A1
CRD4299-1 AMR
MC78L05 regulates the AMR +12 V supply down
to provide a clean +5 V analog supply for the
CS4299. The MC78L05 regulator can provide adequate current, which is enough for the CS4299 and
associated analog circuitry.
2.3 Analog I/O
The CS4299 has many analog inputs and outputs
that may or may not be used depending on the sys-
tem’s application. Unused inputs should be tied to
Vrefout (pin 28) or AC coupled via a 0.1 µF capacitor to the analog ground plane. The analog section
contains the components for a headphone amplifier. The Modem Audio, CD In, Audio In, and Aux
In headers are also part of the Analog I/O secti on.
The header and its associated components may or
may not be necessary depending on the audio inputs implemented.
2.4 Audio I/O
A full feature set of the CS4299’s analog I/O and
digital out is represented on the reference design
card through internal and external connectors:
•Line Out
• Headphone Out
•Line In
•Mic In
• CD Audio In
put voltage of 1 Vrms. The Line Out connection is
made via an external 1/8" jack.
• Maximum output level: 1 Vrms
2.4.2 Headphone Out
An external 1/8" jack is provided for a headphone
connection. This output is driven by an amplifier
for low impedance loads such as 32 Ω headphones.
• Maximum output level: 2.0 Vrms (no load);
1.5 Vrms (32 Ω load)
• Maximum output power: 70 mW/channel
(32 Ω load)
2.4.3 Line In
The Line In 1/8" jack provides an input to the Line
In pins of the CS4299.
• Maximum input level: 2 Vrms
2.4.4 Mic In
The Microphone In 1/8" jack provides an input to a
microphone pre-amplifier circuit that applies 18 dB
of gain to the signal.
• Maximum input level:
- Microphone Boost enabled: 12.5 mVrms
- Microphone Boost disabled: 125 mVrms
• Supports 3-pin electret (power on ring) and 2pin dynamic microphones
• Aux In
•Video In
• Modem Audio connection
• Optical Digital Out
Four external 1/8" jacks, one external TOS-LINK
jack, and four internal header connections are used
for analog and digital inputs and outputs.
2.4.1 Line Out
The output of the CS4299 is capable of driving impedances greater than 10 kΩ with a maximum out-
DS319RD1A1 5
2.4.5 CD Audio In
The CD Audio input provides a 4-pin (0.1 inch center) right-angled connector that is compatible with
the SONY standards and ATAPI.
• Maximum input level: 2 Vrms
• Pseudo differential input using the CD Common pin as the ground
• 0.1 inch connector wired as:
- Pin 1 : Left Channel
- Pin 2 : Common return
CRD4299-1 AMR
- Pin 3 : Common return
- Pin 4 : Right Channel
2.4.6 Aux In
• Internal 4-pin (0.1 inch center) right-angled
connector
•Wired as:
- Pin 1 : Left Channel
- Pin 2 : Analog Ground
- Pin 3 : Analog Ground
- Pin 4 : Right Channel
• Maximum input level: 2 Vrms
2.4.7 Video In
• Internal 4-pin (0.1 inch center) right-angled
connector
- Pin 1 : Left Channel
- Pin 2 : Analog Ground
- Pin 3 : Analog Ground
- Pin 4 : Right Channel
• Maximum input level: 2 Vrms
2.4.8 Modem Audio Connection
The modem audio connection can be made through
the internal 4-pin (0.1 inch center) right-angled
connector. This connector carries both a mono input and a mono output.
• Internal 4 pin header (0.1 inch center)
- Pin 1 : Mono Out (to modem)
- Pin 2 : Analog Ground
- Pin 3 : Analog Ground
- Pin 4 : Phone In (from modem)
• Maximum input level: 1 Vrms
• Maximum output level: 1 Vrms
• Minimum load impedance: 10 kΩ
3. SCHEMATIC DESCRIPTION
Figures 11 through 17 show the schematics for the
CRD4299-1 AMR card. This section will describe
particular pages of the schematic that need to be
discussed.
3.1 Figure 11: Block Diagram
The block diagram is an interconnection overview
between schematic pages.
3.2 Figure 12: AMR Bus Interface
The +5 V power pin is decoupled through C1 and
supplies power for the SPDIF_OUT circuit. All
ground pins are tied to digital ground except for B2,
which is tied to analog ground.
The AC-link, which consists of ASDOUT, ARST#,
ASYNC, ASDIN, and ABITCLK, transfers digital
audio data between the audio codec and the host.
PC_BEEP_BUS routes the beep/speaker signal
from the motherboard to the audio subsystem, for
use in hearing POST codes (refer to the Intel Au-
dio/Modem Riser Specification [2]).
The PRIMARY_DN# signal indicates the presence
or the absence of a primary codec on the motherboard. The MSTRCLK is the 24.576 MHz master
clock for the AC ‘97 link. Populate R51 when the
Codec is the primary codec. Populate R50 when the
Codec is the secondary codec.
The CS4297 does not support S/PDIF. Iin this case,
R3 should be populated so the S/PDIF signal originates from the AMR bus. For a CS4297A/99, by
populating R2 instead of R3, the S/PDIF signal
originates from the codec, bypassing the AMR bus.
3.3 Figure 13: Power Supply
The CS4299 requires both a digital +3.3 V and an
analog +5 V supply. The digital power is supplied
from the AMR bus. A separate regulator is recommended for the analog voltage supply to provide
good audio signal quality. A Motorola MC78L05
regulates the +12 V supply from the AMR bus
6 DS319RD1A1
CRD4299-1 AMR
down to a clean +5 V analog supply. Two packaging options are supported, where U5 is an SO8 surface mount package and U4 is a TO-92 pin-in-hole
package. The -12 V power pin is decoupled
through C73/C74, and supplies power to the headphone circuit.
3.4 Figure 14: CS4299 AC ‘97 Audio Codec
For the best audio performance, the analog voltage
regulator, an MC78L05, is located near the
CS4299. A 10 µ F electrolytic capacitor should be
added next to pins 25 and 26 if the capacitor connected to the output of the power regulator is located far away from the CS4299. All filtering
capacitors of audio signals are NPO-type to ensure
minimal added distortion. Two footprints are provided for the crystal: a CA-301 pin-in-hole footprint, Y1, for miniature crystal; and a short height
HC-49S package, Y2. R47 is a termination resistor
in the serial AC-link between the CS4299 and the
AMR bus.
common return path for both the left and right
channels. Therefore, the input impedance of this
block is half of that of the other inputs.
The modem connection is both a mono input and
output. The output is fed from the CS4299’s
MONO_OUT pin through a divider made of
R22/23. The divider ratio is preset to 0 dB for an
output voltage of 1 Vrms. If a lower output voltage
is desired, the resistors can be replaced with appropriate values, as long as the total load on the output
is kept greater than 10 kΩ. The input is not divided
to accommodate line level sources up to 1 Vrms.
3.6 Figure 16: Audio Outputs
The line out is driven directly by the CS4299. The
headphone out amplifier, a Motorola MC1458, is
capable of driving stereo headphones with impedances greater than 32 Ω or powered speakers.
R37/38 are added for short-circuit protection. An
optical S/PDIF (IEC 958 consumer) output is also
supported.
3.5 Figure 15: Analog Inputs
The inputs for AUX, VIDEO, CD, and LINE are
passed through voltage dividers that reduce the levels by 6 dB to allow connection of line level sources up to 2 Vrms. The 220 pF capacitors are
provided on Line_In, Mic_In, CD_In, Aux_In,
Video_In, and Internal Modem connection for
EMC suppression. These may be removed if EMC
testing determines they are not required. 1 µF ACcoupling capacitors are used on the Line_In,
Mic_In, CD_In, Aux_In, Video_In, and Internal
Modem circuit to minimize the low frequency rolloff. The internal CD audio connection utilizes a
pseudo-differential interface with CD_GND as the
3.7 Figure 17: Microphone Pre-amp and Bias
A Motorola MC33078D low noise dual op-amp
provides an +18 dB gain stage f or the microphone
and buffers the phantom power supply for the mic.
The phantom power is derived from the +5 V analog supply and buffered by U1A to provide a maximum of 4.2 V with no load and a minimum of
2.0 V under a 0.8 mA load on the ring. Hardware
rolloffs were implemented at 60 kHz and 15 kHz as
recommended by the PC 99 System Design Guide,
Chapter 17, Audio Components [5].
DS319RD1A1 7
CRD4299-1 AMR
3.8 Component Selection
Great attention was given to the particular components on the CRD4299-1 AMR board with cost,
performance, and package selection as the most important factors. Listed are some of the guidelines
used in the selection of components:
• No components smaller than 0805 package
• Use single package components, no resistor
packs
• Right-angled headers for all internal connections to provide sufficient headroom for the
jacks
• Dual footprint for XTAL. HC-49S, and small
circular CA-301 pin-in-hole package
• Dual footprint for +5 V regulator. Surface
mount and pin-in-hole package are supported.
3.9 EMC Components
A number of capacitors and inductors are included
to help the board meet EMC compliance tests, such
as FCC Part 15. Modifying this selection of components without EMC testing could cause EMC compliance failure.
4. GROUNDING AND LAYOUT
onto these pins. All data converters are highly susceptible to noise on the crystal pins.
A separate chassis ground provides a reference
plane for all of the EMC components. The chassis
ground plane is connected to the analog ground
plane at the external jacks.
4.2 CS4299 Layout Notes
Please refer to the CS4299 Datasheet [3] on how
the area under the chip should be partitioned and
how the bypass capacitors should be placed. Pay
close attention to the suggestions for the bypass capacitors on REFFLT, AFLT1, AFLT2, and the
power supply capacitors. The pinout of the CS4299
is designed to keep digital and analog signals from
crossing when laying out the board.
5. AUDIO PERFORMANCE EVALUATION
In the below reference designators, the letters in parenthesis designate the full-scale value for that particular I/O.These reference designators are used in
the following tables to help clarify which full-scale
value applies to the particular measurement. Values referenced to digital numbers on the PC are listed with the (d) suffix.
4.1 Partitioned Voltage and Ground Planes
The pinout of the CS4299 allows the ground split to
completely separate digital signals on one side and
analog signals on the other. This split is located
very close to the CS4299 so analog and digital
ground return currents originating from the
CS4299 may flow through their respective ground
planes. A bridge is made across the split to maintain the proper reference potential for each ground
plane.
The area around the crystal oscillator and the two
XTAL signals is filled with copper on the top and
bottom sides and attached to digital ground. This
ground plane serves to keep noise from coupling
8 DS319RD1A1
5.1 Plots
In the following plots, stereo measurements have
two sets of data per plot and two vertical axes.
Above each vertical axis is a label indicating a
channel that relates to that axis. The data set extends beyond the vertical axis to indicate its association with that axis. Using Figure 1 as an example,
the top set of data extends beyond the right vertical
axis, which is labeled at the top “RIGHT’, indicating that the top set of data is the right channel and
associated with the right vertical axis. Likewise,
the bottom set of data extends beyond the left vertical axis which is labeled at the top “LEFT”, indicating that the bottom set of data is the left channel
and associated with the left vertical axis.
CRD4299-1 AMR
Signal Name Connector Maximum Voltage Reference
Line In (A-D-PC-D-A) Jack 2.376 V
Line In (A-A) Jack 2.142 V
Mic In Jack 0.128 V
Line Out Jack 1.021 V
RMS
RMS
RMS
RMS
Designator
0 dB FS (li)
0 dB FS (li)
0 dB FS (mi)
0 dB FS (lo) N/A
Imp.
(k
Table 1. Reference Designators
Microphones Supported Support Comments
3-Pin Phantom Power (power on ring) Yes
2-Pin Dynamic Yes
2-Pin Phantom Power (power on tip)
Table 2. Microphone Support Specifications
Full Duplex (A-D-PC-D-A):
Line In to Line Out Reference Left Right Units Figures
Dynamic Range -91.4 -91.4 dB FS A (lo) 99 - 1NXL
THD+N -3 dB FS (li) -85.2 -85.2 dB FS (lo) 99 - 1DXL
Frequency Response Ac = -0.4 dB 20-20k 20-20k Hz 99 - 1MXL
NOTE: TM004: combined test used in lieu of TM002 and TM003
Ω)
Table 3. Full Duplex Specifications
Analog Mixer (A-A):
Line In to Line Out Reference Left Right Units Figures
Dynamic Range -95.8 -95.7 dB FS A (lo) 99 - 1NAL
THD+N -3 dB FS (li) -92.9 -92.9 dB FS (lo) 99 - 1DAL
Frequency Response Ac = +-0.2 dB 20-20k 20-20k Hz 99 - 1MAL
Crosstalk f = 10 kHz -66.8 -66.5 dB FS (lo) 99 - 1CAL
Table 4. Analog Mixer, Line In to Line Out Specifications
Analog Mixer (A-A):
Mic In to Line Out Reference Left Right Units Figures
Dynamic Range Gain = 0 dB -94.1 N/A dB FS A (lo) 99 - 1NAM
THD+N -3 dB FS (mi) -91.3 N/A dB FS (lo) 99 - 1DAM
Frequency Response Ac = -3 dB 50-15k N/A Hz 99 - 1MAM
NOTE: Mic In is Mono
Table 5. Analog Mixer, Mic In to Line Out Specifications
DS319RD1A1 9
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