Copyright
Cirrus Logic, Inc. 1998
(All Rights Reserved)
CRD4297-1 AMR
Advanced Product Databook
CrystalClear™
AC '97 AMR Audio Modem
Riser Reference Design
FEATURES
■AMR Audio Codec add-in card designed to meet
the Intel® Audio/Modem Riser Specification
■High quality, low cost, 2-layer, single sided
adapter board
■CS4297 SoundFusion™ Audio Codec ’97
■Complete suite of Analog and Digital I/O
connections:
— Line In, Line Out, Mic In, Modem Audio connection, CD
Audio In, Vi deo In, Aux In, Headphone O ut and Optic al
Digital Out
■Meets or exceeds Microsoft’s® PC 97, PC 98, and
PC 99, both required and advanced, audio
performance requirements.
DESCRIPTION
The CRD4297-1 AMR add-in board reference design
showcases Cirrus Logic’s Crystal Audio AC ’97
CS4297 SoundFusion Audio Codec ’97, and is Au-
dio/Modem Riser Specification[2], compliant. The
CRD4297-1 AMR card is 2.7" high by 3.6" long.
The CRD4297-1 AMR reference design includes a cus-
tomer re ady manufa ctur ing kit. Inc luded in the k it are a
full set of schematic design files (OrCAD® 7.2 format),
PCB job files (PADS® ASCII), PCB artwork files,
bracket drawings (Gerber), and bill of materials. The de-
sign is production ready as is, or can be easily
modified to incorporate specific OEM changes. Docu-
mentation source files are availa ble to assist the OEM
to quickly provide an accurate end user manual.
ORDERING INFO CRD4297-1 AMR
DS242RD1B1 DEC ‘98
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
2DS242RD1B1
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
GENERAL INFORMATION
The CRD4297-1 AMR is a production-grade
AMR audio card reference design using the
CS4297 SoundFusion Audio Codec ‘97. The de-
sign supports the functionally compatible CS4297,
CS4297A, or CS4299 AC ‘97 SoundFusion Audio
Codecs.
The AMR board advantage lies in the complete
separation of the analog section from the noisy dig-
ital environment of a personal computer. A 5-wire
digital link is all that is required to connect the au-
dio codec to the AMR 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 CS4297 performs the Digital-to-
Analog Conversion (DAC) for the digital audio
output stream and also provides multiple analog
audio inputs and outputs, analog mixing and Ana-
log-to- Digital Conversion (ADC).
This card is designed to provide the highest possi-
ble functionality, along with industry leading audio
performance at a low manufacturing cost. Care was
taken with component placement and signal rout-
ing to minimize sources that can degrade audio per-
formance. Cirrus’ analog design know-how has
resulted in a board that preserves the exceptional
analog performance of the CS4297.
REFERENCE DESIGN FEATURES
The CRD4297-1 A MR reference design illustrates
a high quality, low cost two-layer add-in card lay-
out. The card is sectioned into three main parts: the
AMR bus section, the CS4297 Audio Codec ‘97
section, and the Analog I/O section.
Digital Audio Out
The AMR bus provides digital out in a format com-
patible 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 sig-
nal originates either from the AMR bus or the co-
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 er-
ror rates, small size, and cost efficiency. The signal
is IEC 958 and CP-1201 compliant.
CS4297 Audio Codec ‘97
The CS4297 is a mixed-signal serial Codec based
on the AC ‘97 specification. It is designed to be
paired with a digital controller, located on the
AMR bus. The AC ‘97 Controller is responsible for
all communications between the CS4297 and the
rest of the system. The CS4297 functions as an an-
SoundFusion and CrystalClear are trademarks of Cirrus Logic, Inc.
Intel is a registered trademark of Intel Corporation.
OrCAD is a registered t ra demark of O rCA D, Inc.
PADS is a registered trademark of, PADS Software, Inc.
Microso ft, Windows, an d D irectX are regi st er ed trademar ks of Micros of t Co rporation.
Preliminary product information describes products which are in production, but for which full characterization data is not yet available.
Advance pr oduct infor m at i on describe s pr oducts whic h ar e i n developm ent an d subject to developm ent changes. Cirrus Logic, In c.
has made best efforts to ensure that the information contained in this document is accurate and reliable. However, the information is
subject t o change with out not i ce and is provid ed “AS IS” witho ut w arranty of any kind (express or implied). No r esp onsibility is as-
sumed by C irr us Logic, Inc. fo r the use of this info rm a tion, nor for infr ingements of pat ent s or other right s of th ird parties. This docu-
ment is the pr operty of Cir ru s Logic, Inc. a nd implies no license under patents, c opyrights, trademarks, or tr ad e secrets. No part of
this publication may be copied, reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, me-
chanical, photographic, or otherwise). 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 jurisdic-
tions. A list of Cirrus Logic, Inc. trademarks and service marks can be found at http://www.cirrus.com.
DS242RD1B1 3
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
alog mixer, a stereo ADC, a stereo DAC, and a con-
trol and digital aud io stream interface to the AC ‘97
controller.
The CS4297 contains two distinct functional sec-
tions: digital and analog. The digital section in-
cludes the AC-link registers, power management
support, SYNC detection circuitry, and AC-link se-
rial port interface logic. The analog section in-
cludes the analog input multiplexer (mux), stereo
output mixer, mono output mixer, stereo ADCs,
stereo DACs, and analog volume controls. This
section contains the components for the various an-
alog audio connections, a nd the 24.576 MHz crys-
tal master clock. For more information refer to the
CS4297 Data Sheet [3]. The capacitors required for
the CS4297 and their placement are discussed in
the CS4297 Data Sheet [3]. Refe r to the Grounding
and Layout section of the data sheet for the recom-
mended routing of the audio section.
Power Requirements
The CS4297 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 recom-
mended for the analog supply. A Motorola
MC78L05 regulates the AMR +12 V supply down
to provide a clean +5 V analog supply for the
CS4297. The MC78L05 regulator can provide ade-
quate current, which is enough for the CS4297 and
associated analog circuitry.
Analog I/O
The CS4297 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 capacitively coupled via 0.1 µF
to the analog ground plane. The analog section con-
tains 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 section. The
header and its associated components may or may
not be necessary depending on the audio inputs im-
plemented.
Audio I/O
A full feature set of the CS4297’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
• 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.
Line Out
The output of the CS4297 is capable of driving im-
pedances greater than 10 kΩ with a maximum out-
put voltage of 1 Vrms. The Line Out connection is
made via an external 1/8" jack.
• Maximum output level: 1 Vrms
Headphone Out
An external 1/8" jack 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)
4DS242RD1B1
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
Line In
The Line In 1/8" jack provides an input to the Line
In pins of the CS4297.
• Maximum input level: 2 Vrms
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 2-
pin dynamic microphones
CD Audio In
The CD Audio input provides a 4-pin (0.1 inch cen-
ter) right-angled connector that is compatible with
the SONY standard.
• Maximum input level: 2 Vrms
• Differential input using the CD Comm on pin as
the ground
• 0.1 inch connector wired as:
- Pin 1 : Left Channel
- Pin 2 : Analog Ground
- Pin 3 : Analog Ground
- Pin 4 : Right Channel
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
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
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 in-
put 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
SCHEMATIC DESCRIPTION
Figures 11 through 17 show the schematics for the
CRD4297-1 AMR card. This section will describe
particular pages of the schematic that need to be
discussed.
Figure 11: Block Diagram
The block diagram is an interconnection over view
between schematic pages.
Figure 12: AMR Bus Interface
The +5 V power pin is decoupled through C1 and
supplies power for the SPDIF_OUT circuit. All
DS242RD1B1 5
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
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 motherboard
beep/speaker signal from the motherboard to the
audio subsystem, for use in hearing POST codes
(refer to the Intel Audio/Modem Riser Specification
[2]).
The PRIMARY_DN# signal indicates the presence
or the absence of a primary codec on the mother-
board. The MSTRCLK is the 24.576 MHz master
clock for the AC ‘97 link. Populate R51 since the
CS4297 is always the primary codec. Populate R50
for CS4297A/99, when they are the secondary c o-
dec.
The CS4297 does not support S/PDIF, R3 is popu-
lated so the S/PDIF signal originates from the
AMR bus. For a CS4297A/99 by populating R2 in-
stead of R3, the SPDIF_CODEC signal is directly
routed to the S/PDIF circuit, bypassing the AMR
bus.
Figure 13: Power Supply
The CS4297 requires both a digital +3.3 V and an
analog +5 V supply. The digital power is supplied
from the AMR bus. A sepa rate regula tor is rec om-
mended for the analog voltage supply to provide
good audio signal quality. A Motorola MC78L05
regulates the +12 V supply from the AMR bus
down to a clean +5 V a nalog supply. Two packag-
ing options are supported, where U5 is an SO8 sur-
face 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 head-
phone circuit.
Figure 14: CS4297 AC ‘97 Audio Codec
For the best audio performance, the analog voltage
regulator, an MC78L05, is located near the
CS4297. A 10 µF electrolytic capacitor should be
added next to pins 25 and 26 if the capacitor con-
nected to the output of the power regulator is locat-
ed far away from the CS4297. All filtering
capacitors of audio signals are NPO-type to ensure
minimal added distortion. Two footprints are pro-
vided for the crystal XTAL: a CA-301 pin-in-hole
footprint, Y1, for miniature crystal; and a standard
HC-49U package, Y2. The HC-49U package can
be bent over and soldere d to the ca rd. R47 is a ter -
mination resistor in the serial AC-link between the
CS4297 and the AMR bus.
Figure 15: Analog Inputs
The inputs for AUX, VIDEO, CD, and LINE are
passed through a divider circuit that reduces the
voltage 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 AC-
coupling capacitors are used on the Line_In,
Mic_In, CD_In, Aux_In, Video_In, and Internal
Modem circuit to minimize the low frequency roll-
off. The internal CD audio connection utilizes a
pseudo-differential interfac e with CD_GND as the
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 CS4297’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 appro-
priate 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.
Figure 16: Audio Outputs
The line out is driven directly by the CS4297. The
headphone out amplifier, a Motorola MC1458, is
6DS242RD1B1
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
capable of driving stereo headphones with imped-
ances 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.
Figure 17: Microphone Pre-amp and Bias
A Motorola MC33078D low noise dual op-amp
provides an +18 dB gain stage for the microphone
and buffers the phantom power supply for the mic.
The phantom power is derived from the +5 V ana-
log supply and buffered by U1A to provide a max-
imum of 4.2 V with no load and a minimum of
2.0 V under a 0.8 mA load on the ring, a s require d
by the PC 99 System Design Guide, Chapter 17,
Audio Components [5].
Component Selection
Great attention was given to the particular compo-
nents on the CRD4297-1 AMR board with cost,
performance, and package selection as the most im-
portant 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 connec-
tions to provide sufficient headroom for the
jacks
• dual footprint for XTAL. Standard H49U with
GND pad and small circular CA-301 pin-in-
hole package
• Dual footprint for +5 V and +3.3 V regulators.
Surface mount and pin-in-hole package are
supported.
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 compo-
nents without EMC testing could cause EMC com-
pliance failure.
GROUNDING AND LAYOUT
Partitioned Voltage and Ground Planes
The pinout of the CS4297 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 CS4297 so analog and digital
ground return currents originating from the
CS4297 may flow through their respective ground
planes. A bridge is made across the split to main-
tain the proper refe rence 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
onto these pins. All data converters are highly sus-
ceptible 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.
CS4297 Layout Notes
Please refer to the CS4297 Data Sheet [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 ca-
pacitors on REFFLT, AFLT1, AFLT2, and the
power supply capacitors. The pinout o f the CS4297
is designed to keep digital and analog signals from
crossing when laying out the board.
DS242RD1B1 7
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
AUDIO PERFORMANCE EVALUATION
In the above reference designators, the letters in pa-
renthesis designate the full-scale value for that par-
ticular I/O. These are used in the tables below to
help clarify which full-scale value applies to the
particular measurement. Values referenced to dig-
ital numbers on the PC are listed with the (d) suffix.
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 ex-
tends beyond the vertical axis to indicate its associ-
ation with that axis. Using Figure X as an example,
the top set of data extends beyond the right vertical
axis, which is labeled at the top “RIGHT’, indicat-
ing that the top set of data is the right channel and
associated with the right vertical axis. Likewise,
the bottom set of data extendds beyond the left ver-
tical axis which is labeled at the top “LEFT”, indi-
cating that the bottom set of data is the left channel
and associated with the left vertical axis.
Signal Name Connector Maximum Voltage Reference
Designator Imp. (kΩ)
Line In Jack 2.341 VRMS 0 dB FS (li)
Mic In Jack 0.14 6 VRMS 0 dB FS (mi)
Line Out Jack 1.058 VRMS 0 dB FS (lo) N/A
Speaker Out (8Ω) N/A N/A 0 dB FS(so) N/A
Microphones Supported Support Comments
3-Pin Phantom Power (power on ring) Yes
2-Pin Dynamic Yes
2-Pin Phantom Power (power on tip)
Full Duplex (A-D-PC-D-A):
Line In to Line Out Reference Left Right Units Figures
Dynamic Range 83.8 83.8 dB FS A (lo) 97 - 1NXL
THD+N -3 dB FS (li) -81.1 -80.5 dB FS (lo) 97 - 1DXL
Frequency Response Ac = -0.25 dB 20-20k 31-20k Hz 97 - 1MXL
NOTE: TM004: combined test used in lieu of TM002 and TM003
Analog Mixe r (A-A) :
Line In to Line Out Reference Left Right Units Figures
Dynamic Range 95.4 95.3 dB FS A (lo) 97 - 1NAL
THD+N -3 dB FS (li) -91.2 -90.6 dB FS (lo) 97 - 1DAL
Frequency Response Ac = -0.1 dB 20-20k 20-20k Hz 97 - 1MAL
Crosstalk f = 10 kHz -66.7 N/A dB FS (lo) 97 - 1CAL
Analog Mixe r (A-A) :
Mic In to Line Out Reference Left Right Units Figures
Dynamic Range Gain = 0 dB 93.9 N/A dB FS A (lo) 97 - 1NAM
THD+N -3 dB FS (mi) -85.9 N/A dB FS (lo) 97 - 1DAM
Frequency Response Ac = -3 dB 58-15.5k N/A Hz 97 - 1MAM
NOTE: Mic In is Mono
8DS242RD1B1
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
CwGRAPH 0.65 CrystalWare(tm)
20 100 1 k 10 k 20 k
3
2
1
0
-1
-2
-3
-4
-5
-6
-7
6
5
4
3
2
1
0
-1
-2
-3
-4
97-1\97-1MXL.ADXLEFT RIGHT
Frequency (Hz)
Amplitude (dB)
Amplitude (dB)
Figure 1. Full Duplex (A-D-PC-D-A): Line In/Out Frequency Response
CwGRAPH 0.65 CrystalWare(tm)
20 100 1 k 10 k 20 k
-60
-65
-70
-75
-80
-85
-90
-95
-100
-105
-110
-50
-55
-60
-65
-70
-75
-80
-85
-90
-95
-100
97-1\97-1NXL.ADXLEFT RIGHT
Frequency (Hz)
Dynamic Range (dB FS A)
Dynamic Range (dB FS A)
Figure 2. Full Duplex (A-D-PC-D-A): Line In/Out Dynamic Range
DS242RD1B1 9
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
CwGRAPH 0.65 CrystalWare(tm)
20 100 1 k 10 k 20 k
-60
-65
-70
-75
-80
-85
-90
-95
-100
-105
-110
-50
-55
-60
-65
-70
-75
-80
-85
-90
-95
-100
97-1\97-1DXL.ADXLEFT RIGHT
Frequency (Hz)
THD+N (dB FS)
THD+N (dB FS)
Figure 3. Full Duplex (A-D-PC-D-A): Line In/Out THD+N v s. Frequency
CwGRAPH 0.65 CrystalWare(tm)
20 100 1 k 10 k 20 k
3
2
1
0
-1
-2
-3
-4
-5
-6
-7
6
5
4
3
2
1
0
-1
-2
-3
-4
97-1\97-1MAL.ADXLEFT RIGHT
Frequency (Hz)
Amplitude (dB)
Amplitude (dB)
Figure 4. Analog Mixer (A-A): Line In/Out Frequency Response
10 DS242RD1B1
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
CwGRAPH 0.65 CrystalWare(tm)
20 100 1 k 10 k 20 k
-60
-65
-70
-75
-80
-85
-90
-95
-100
-105
-110
-50
-55
-60
-65
-70
-75
-80
-85
-90
-95
-100
97-1\97-1NAL.ADXLEFT RIGHT
Frequency (Hz)
Dynamic Range (dB FS A)
Dynamic Range (dB FS A)
Figure 5. A nalog Mixer (A-A): Line In/Out Dynamic Range
CwGRAPH 0.65 CrystalWare(tm)
20 100 1 k 10 k 20 k
-60
-65
-70
-75
-80
-85
-90
-95
-100
-105
-110
-50
-55
-60
-65
-70
-75
-80
-85
-90
-95
-100
97-1\97-1DAL.ADXLEFT RIGHT
Frequency (Hz)
THD+N (dB FS)
THD+N (dB FS)
Figure 6. Analog Mixer (A-A): Line In/Out THD+N vs. Frequency
DS242RD1B1 11
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
CwGRAPH 0.65 CrystalWare(tm)
20 100 1 k 10 k 20 k
3
2
1
0
-1
-2
-3
-4
-5
-6
-7
97-1\97-1MAM.ADX
Frequency (Hz)
Amplitude (dB)
Figure 7. Anal og Mixer (A-A): Mic In/Line Out Frequency Respon se
CwGRAPH 0.65 CrystalWare(tm)
20 100 1 k 10 k 20 k
-60
-65
-70
-75
-80
-85
-90
-95
-100
-105
-110
97-1\97-1NAM.ADX
Frequency (Hz)
Dynamic Range (dB FS A)
Figure 8. Analog Mixer (A-A): Mic In/Line Out Dynamic Range
12 DS242RD1B1
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
CwGRAPH 0.65 CrystalWare(tm)
20 100 1 k 10 k 20 k
-60
-65
-70
-75
-80
-85
-90
-95
-100
-105
-110
97-1\97-1DAM.ADX
Frequency (Hz)
THD+N (dB FS)
Figure 9. Analog Mixer (A-A): Mic In/Line Out THD+N vs. Frequency
CwGRAPH 0.65 CrystalWare(tm)
20 100 1 k 10 k 20 k
-50
-55
-60
-65
-70
-75
-80
-85
-90
-95
-100
97-1\97-1CAL.ADX
Frequency (Hz)
Crosstalk ( dB)
Figu re 10. Analog Mixer (A-A): Line In/Ou t Cros stalk vs. Fre q uency
DS242RD1B1 13
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
REFERENCES
1) Intel, Audio Codec ‘97 Component
Specification, Revision 2.1,
http://developer.intel.com/pc-supp/
platform/ac97/
2) Intel, Audio/Modem Riser Specification,
Revision 1.01, Sep 10, 1998.
http://developer.intel.com/pc-
supp/platform/ac97/INDEX.HTM
3) Cirrus Logic, CS4297 SoundFusion Audio
Codec ‘97 Data Sheet, July 1998.
http://www.cirrus.com/products/overviews/
cs4297.html
4) Steve Harris, Clif Sanchez, Personal Computer
Audio Quality Measurements, Ver 0.5
http://www.cirrus.com/products/papers/
meas/meas.html
5) Intel and Microsoft, PC 99 System Design
Guide
http://www.microsoft.com/hwdev/desguid/
6) M. Montrose. Printed Circuit Board Design
Techniques for EMC Compliance, IEEE Press,
New York: 1996.
ADDENDUM
• Schematic drawings
• Layout drawings
• Bracket drawing
• Bill of materials
14 DS242RD1B1
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
AUDIO_IN
AUDIO_IN
VIDEO_R
VIDEO_L
AUX_INR
AUX_INL
CD_INR
CD_INL
CD_COM
LINE_IN_R
LINE_IN_L
MONO_OUT
PHONE_IN
PC_BEEP
PC-BEEP-BUS
AUDIO_MICIN
AUDIO_MICIN
MIC1
CS4297
CS4297
CD_INR
LINE_IN_R
CD_INL
ASYNC
ARST#
LINE_OUT_R
LINE_OUT_L
ASDOUT
ASDIN
PHONE_IN
MONO_OUT
PC_BEEP
ALT_LINE_OUT_R
S/PDIF_CODEC
PRIMARY_DN#
ABITCLK
CD_COM
LINE_IN_L
MIC1
ALT_LINE_OUT_L
AUX_INL
AUX_INR
VIDEO_L
VIDEO_R
MSTRCLK
AMR_BUS
AMR_BUS
ARST#
ABITCLK
ASYNC
ASDIN
ASDOUT
PRIMARY_DN#
MSTRCLK
S/PDIF_OUT
S/PDIF_CODEC
PC_BEEP_BUS
AUDIO_OUT
AUDIO_OUT
ALT_LINE_OUT_L
ALT_LINE_OUT_R
LINE_OUT_R
LINE_OUT_L
SPDIF_OUT
POWER
POWER
PC_BEEP
CD_INL
CD_COM
CD_INR
LINE_IN_L
LINE_IN_R
AUX_INL
AUX_INR
VIDEO_L
VIDEO_R
PHONE_IN
MONO_OUT
MIC1
PC_BEEP_BUS
SPDIF_CODEC
ASDOUT
ASDIN
ASYNC
ABITCLK
ARST#
PRIMARY_DN#
MSTRCLK
ALT_LINE_OUT_R
ALT_LINE_OUT_L
LINE_OUT_L
LINE_OUT_R
SPDIF_OUT
Figure 11. Block Diagram
DS242RD1B1 15
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
AMR BU
S
populate R2 for
CS4299 board
populate R3 for
CS4297 board
populate R51 if
populate R50 if
secondary AMR
device.
DGN
D
DGN
D
+12V
D
+3.3
VD
+5VD
AGND
+3.3V
D
DGN
D
DGN
D
+5V
D
CGN
D
-12V
D
KE
Y
KE
Y
KE
Y
KE
Y
P1
AMR CONNECTO
R
B1
B2
B3
B4
B5
B6
B7
B8
B9
B10
B11
B12
B13
B14
B15
B16
B17
B18
B19
B20
B21
B22
B23
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
A15
A16
A17
A18
A19
A20
A21
A22
A23
AUDIO_MUTE#
GND
MONO_OUT/PC_BEEP
RSVD
RSVD
PRIMARY_DN#
-12V
GND
+12V
GND
+5VD
GND
RSVD
RSVD
+3.3VD
GND
AC97_SDATA_OUT
AC97_RESET#
AC97_SDATA_IN3
GND
AC97_SDATA_IN2
GND
AC97_MSTRCLK
AUDIO_PWRDN
MONO_PHONE
RSVD
RSVD
RSVD
GND
+5Vdual/+5VSB
USB_OC
GND
USB+
USB-
GND
S/PDIF_IN
GND
+3.3Vdual/+3.3VSB
GND
AC97_SYNC
GND
AC97_SDATA_IN1
GND
AC97_SDATA_IN0
GND
AC97_BITCLK
C2
0.1uF
Z5U
R3
0
R2
0
M1
HO
LE
1
M3
TOOLH
OLE
M2
HO
LE
1
+
C1
10UF
12
+
C3
10UF
12
R50
47
R51
47
ARST
#
ABI
TCLK
ASYNC
ASDIN
AS
DOUT
PRIMARY_DN#
MSTRCL
K
S/PDIF_OUT
S/PDIF_CODEC
PC
_BEEP_BUS
Figure 12. AMR Bus
16 DS242RD1B1
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
POWER SUPPLIES
Connect AGND to DGND with a 50 mil trace near the 4297
Connect CGND to DGND with a 50 mil trace near the finger
edge of the board.
SURFACE MOUNT
POPULATION
OPTION
PIN IN HOLE
POPULATION
OPTION
Do not populate U5
AGND
-12VA
-12VD
+12VD +12VA
AGND
+5VA
AGNDAGND
+
C70
100uF
U5 MC78L05ACD
18
2
36
7
5 4
VOUTVIN
GND1
GND2GND3
GND4
NC2 NC1
C71
0.1uF
Z5U
C74
0.1uF
Z5U
+
C72
10UF
C73
100uF
L1
31@100MHz
L2
31@100MHz U4
MC78L05
3 1
IN OUT
Figure 13. Power Supplies
DS242RD1B1 17
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
la
y
out Y1 on top
of Y2 -- p opulate
onl
y
one XTAL
DO NOT
POPULATE R45
Do not populate
C62, C63 and
R48 for CS4297.
Polpulate C62,
C63 and R48 for
CS4299
+5VA
+3.3VD
AGND
AGND
AGNDDGND +3.3VD
AGNDDGND
AGND
+5VA
DGND
C68
390pF
NPO
C69
390pF
NPO
C51
0.1uF
Z5U
C52
0.1uF
Z5U
C53
0.1uF C54
0.1uF
Z5U
C55
680pF
NPO
Y1
24.576 MHz
R48 0
C62 1000pF
NPO
C65
0.1uF
Z5U
C67
0.1uF
Z5U
C64
1.0uF
C66
1.0uF
C56
680pF
NPO
C57
680pF
NPO
C58
680pF
NPO
C59
680pF
NPO
R45 0
U3 CS4297
36
37
38
39
44
41
42
43
40
34
33
32
31
1
2
3
4
5
6
7
8
10
9
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25 26
27
28
29
30 48
47
46
45
35
LINE_OUT_R
MONO_OUT
AVdd2
ALT_LINE_OUT_L
NC7
ALT_LINE_OUT_R
AVss2
NC6
NC5
FLTO
FLTI
FLT3D
NC1
DVdd1
XTL_IN
XTL_OUT
DVss1
SDATA_OUT
BIT_CLK
DVss2
SDATA_IN
SYNC
DVdd2
RESET#
PC_BEEP
PHONE
AUX_L
AUX_R
VIDEO_L
VIDEO_R
CD_L
CD_GND
CD_R
MIC1
MIC2
LINE_IN_L
LINE_IN_R
AVdd1 AVss1
REFFLT
Vrefout
AFLT1
AFLT2 S/PDIF_OUT
EAPD
ID1#
ID0#
LINE_OUT_L
C63
0.01uF
X7R
Y2
1 2
3
C60
22pF C61
22pF
R47 47
CD_INR
LINE_IN_R
CD_INL
ASYNC
ARST#
LINE_OUT_R
LINE_OUT_L
ASDOUT
ASDIN
PHONE_IN
MONO_OUT
PC_BEEP
ALT_LINE_OUT_R
S/PDIF_CODEC
PRIMARY_DN#
CD_COM
LINE_IN_L
MIC1
ALT_LINE_OUT_L
AUX_INL
AUX_INR
VIDEO_L
VIDEO_R
MSTRCLK
ABITCLK
Figure 14. CS 4297
18 DS242RD1B1
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
VIDEO IN
L
GND
GND
R
AUX IN
CD IN
L
GN
D
GN
D
R
Connect CGND to
AGND at the
jack
LINE IN
MONO OUT
PHONE IN
GND
GND
INTERNAL MODEM CONNECTION
PC SPEAKER IN
L
GND
GND
R
AGND
AGND
AGND
AGN
D
AGN
D
AGN
D
AGN
D
CGN
D
AGN
D
AGND
AGND
AGND
AGND
AGND
AGND
AGND
AGND
AGND
R1
0
6.8
K
R1
1
6.8
K
R5
6.8
K
R6
6.8
K
R14
6.8
K
R15
6.8
K
R18
6.8
K
R19
6.8
K
R7
6.8
K
R4
6.8
K
R9
6.8
K
R8
6.8
K
R12
3.4
K
R13
3.4
K
R1
6
6.8
K
R1
7
6.8
K
R2
0
6.8
K
R2
1
6.8
K
R23
47K
R24
47K
R22
0
C26
0.1uF
Z5U
C1
0
220pF
R31
47K
C1
1
220pF
C12
22
0pF
C19
22
0pF
C21
22
0pF
C22
22
0pF
C2
3
220pF
C24
22
0pF
C1
6
220pF
C17
22
0pF
C1
8
220pF
J1
4X1HD
R-AU
1
2
3
4
J5
4X1HD
R-AU
1
2
3
4
J2
4X1HD
R-AU
1
2
3
4
J3
4X1HD
R-AU
1
2
3
4
J4
PHONO-1
/8
4
3
5
2
1
C4
1uF
X7
R
C8
1uF
X7
R
C1
5
1u
F
X7
R
C25
1u
F
X7R
C2
8
1u
F
X7R
C2
9
1u
F
X7R
C5
1u
F
X7
R
C9
1u
F
X7
R
C1
4
1u
F
X7
R
C2
0
1u
F
X7
R
C1
3
1u
F
X7
R
VIDEO_R
VIDE
O_L
AUX_I
NR
AUX
_INL
CD_INR
CD_INL
CD_C
OM
LINE_IN_R
LINE_IN_L
MONO_OUT
PHONE_IN
PC
_BEEP
PC-B
EEP-BUS
Figure 15. Audio In
DS242RD1B1 19
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
HEADPHONE
JACK
LINE OUT
JACK
Connect CGND to
AGND at the
jack
Connect CGND to
AGND at the
jack
Digital Outp
ut
CGN
D
AGND
CGN
D
AGND
DGND
DGND
DGN
D
+5V
D
AGND
+12VA
+12VA
AGND
AGND
-12VA
-12VA
R37
10
1/4
W
R3
8
10
1/4
W
J1
0
TO
TX-173
1
2
3
4
5
6
R49
8.2
K
U2
A
MC14
58
3
2
1
U2
B
MC14
58
5
6
7
R3
5
27
K
C41
22
pF
R3
6
56
K
R4
3
100
K
R44
100
K
C46
10UF
1
2
C47
10UF
1
2
C4
0
10UF
1
2
C4
2
10UF
1
2
C44
22
0pF
C45
22
0pF
C48
22
0pF
C4
9
220pF
C43
22
pF
C50
0.1uF
Z5U
R3
9
27
K
R4
0
56
K
J9
PHONO-1
/8
4
3
5
2
1
J7
PHONO-1
/8
4
3
5
2
1
AL
T_LINE_OUT_L
ALT_L
INE_OUT_R
LINE_OU
T_R
LINE_
OUT_L
SPDIF_O
UT
Figure 16. Audio Out
20 DS242RD1B1
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
place close to
pins 8 and 4
Connect CGND
to the jack
AGND
AGND
+5VA
AGND
CGND
AGND
AGND
AGND
+5VA
+5VA
AGND
AGND
+5VA
R32 2.7K
R29 47K
R34 47K
C30
0.1uF
Z5U
R33 6.8K
R26
68K
R28
100K
+
C31
10UF
12
+
C37
10UF
12
C35
220pF
C36
220pF
C38 220pF
R27
47K
J6
PHONO-1/8
4
3
5
2
1
R25
47K
+
-
U1A
MC33078D
3
2
1
84
+
-
U1B
MC33078D
5
67
84
C34 1uF
X7R
C33 0.068 uF
X7R MIC1
Figure 17. Mic Pre-Amp
DS242RD1B1 21
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
Figure 18. Assembly Drawing
22 DS242RD1B1
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
Figure 19. Top Layer
DS242RD1B1 23
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
Figure 20. Bottom Layer
24 DS242RD1B1
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
Figure 21. Bracket Drawing
25 DS242RD1B1
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Audio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
BILL OF MATERIALS
CRD4297-AMR
Item Qty Reference Value Type PCB-Footprint Mnfr Part Number Description
1 9 C1,C3,C31,C37,C40,C42,
C46,C47,C72 10UF ELELCT ALUM/10UF/16P PANASONIC ECA-1CM100 ALUM ELECT,10uF,20%,16V,POL
2 12 C2,C26,C30,C50,C51,C52,
C53,C54,C65,C67,C71,
C74
0.1uF Z5U CSN_0805 KEMET C0805C104M5UAC CAP, 0805, Z5U, .1uF, 20%, 50V
3 12 C4,C5,C8,C9,C13,C14,C15,
C20,C25,C28,C29,C34 1uF X7R CSN_1206 VENKEL C1206X7R500-
105KNE CAP, 1206, X7R, 1uF, 10%, 25V
4 18 C10,C11,C12,C16,C17,C18,
C19,C21,C22,C23,C24,
C35,C36,C38,C44,C45,
C48,C49
220pF COG SMT_0805 KEMET C0805C221J5G A C CERM CAP,220pF,5%, 50V, CO G
5 1 C33 0.068 uF X7R CS N_0805 KEM ET C0805C683K5RAC CAP, 0805, X7R , 68000pF, 10%, 50V
6 2 C41,C43 22pF COG S MT_0805 C0805C220GAC CERM CAP,22pF,5%, 50V, CO G
7 5 C55,C56,C57,C58,C59 680pF NPO S MT_0805 K EM ET C0805C681J5GA C CERM CAP, 680pF, 5%, 50V,COG
8 2 C60,C61 22pF COG CC0805 CAP,22pF,SO,0805,5%,50V,COG
9 2 C64,C66 1.0uF Y5V SMT_1206 MURATA GRM42-
6Y5V105Z016BL CE RM CAP,1.0UF,25V,Y5V
10 2 C68,C69 390pF NPO S MT_0805 K EM ET C0805C391J5GA C CERM CAP,390pF, 5%, 50V,C OG
11 2 C70,C73 100uF ELECT PIH PANASONIC ECA-1CM101 ALUM ELECT, 100uF,20%,16V,POL
12 4 J1,J2,J3,J5 4X1HDR-AU CONN CON_MLX_70553 MOLEX 70553-0003 HDR, 4X1, 0.025" PIN, 0.1" CTR, 15u" AU
13 4 J4,J6,J7,J9 PHO NO-1/8 CONN CON_STEREO _LZR LZR ELEC-
TRONICS SJ372 CONN, 1/8" DOUBLE SW . STEREO PHONE
JACK
14 1 J10 TOTX-173 CONN TOTX173 TOSHIBA TOTX173 OPTICAL TOSLINK TRANSMITTE R
15 2 L1,L2 31@100MHz FERRITE IND_FB1206 TDK HF50ACB321611-T IND, FBEAD, 1206, 31@100MHz, 25%
16 2 M1,M2 HOLE
17 1 M3 TOOLHOLE TOOLHOLE
18 1 P1 AMR CON-
NECTOR AMR5V-46
19 2 R3,R22 0 RES RES_0805 PHILIPS 9C08052A0R00 J RES, SO , 0805, 0.5%, 1/10W, META L FILM
20 17 R4,R5,R6,R7,R8,R9,R10,
R11,R14,R15,R16,R17,
R18,R19,R20,R21,R33
6.8K RES RES_0805 PHILIPS 9C 08052A6801F RES, SO, 0805, 6.8K, 1%, 1/10W, METAL FILM
21 2 R12,R13 3.4K RES RES_0805 PHILIPS 9C 08052A3401F RES, SO, 0805, 3.4K, 1%, 1/10W, METAL FILM
22 7 R23,R24,R25,R27,R29,
R31,R34 47K RES RES_0805 PHILIPS 9C 08052A4702J RES, SO, 0805, 47K, 5%, 1/10W, METAL FILM
23 1 R26 68K RES RES_0805 PHILIPS 9C08052A6802J RES, SO, 0805, 68K, 5%, 1/10W, METAL FILM
24 3 R28,R43,R44 100K RES RES_0805 PHILIPS 9C08052A1003J RES, SO, 0805, 100K, 5%, 1/10W, METAL FILM
25 1 R32 2.7K RES RES_0805 PHILIPS 9C 08052A2701J RES, SO, 0805, 2.7K, 5%, 1/10W, METAL FILM
26 2 R35,R39 27K RES RES_0805 PHILIPS 9C08052A2702J RES,27K,SO,0805,5%,1/10W,METAL FILM
27 2 R36,R40 56K RES RES_0805 PHILIPS 9C08052A5602J RES,56K,SO,0805,5%,1/10W,METAL FILM
28 2 R37,R38 10 RE S RES_1206 PHILIPS 9C12063A10R0J RES, SO, 1206, 10, 5%, 1/4W, METAL FILM
29 2 R47,R51 47 RES RES_0805 PHILIPS 9C08052A47R0J RES, SO, 0805, 47, 5%, 1/10W, METAL FILM
DS242RD1B1 26
CRD4297-1 AMR
CrystalClear™ AC '97 AMR Au dio Modem Riser Reference
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
30 1 R49 8.2K RES RES_1206 Philips 9C12063A820J RES,8.2k,SM1206,5%,1/4W
31 1 U1 MC33078D OP AMP SO8 MOTOROLA M C33078D IC, SO, SOIC8, 33078, DUAL OP AMP
32 1 U2 MC1458 SO8 SO8 MOTOROLA MC1458 DUAL HEADPHONE AMP
33 1 U3 CS4297 CODEC QFP48_7X7 CR YSTAL
SEMICOND. CS4279 IC, SO, AC ’97 2.0 SERIAL CODEC w/ SRC
34 1 U4 MC78L05 VREG TO-92 MOTOROLA MC78L05AC 5V POS.VOLT.REG., 100ma
35 1 Y1 24.576 MHz PAR RES, FUND XTL_CA-301 EPSON CA-301_24.576M-C XTL, 24.576MHz, FUND, PAR RES
DO NOT POPULATE
Item Qty Reference Value Type PCB-Footprint Mnfr Part Number Description
1 1 C63 0.01uF CAP CSN_0805 KEMET C0805C103K5RAC CERM CAP, .01uF, 10%, 50V,X7R
2 1 C62 1000pF CAP SMT_0805 K EM ET C0805C102J5GA C CERM CAP, 1000pF, 5%, 50V,COG
3 1 R50 47 RES RES_0805 PHILIPS 9C08052A47R0J RES, SO, 0805, 47, 5%, 1/10W, METAL FILM
4 3 R2,R45,R48 0 RES RES_0805 PHILIPS 9C08052A0R00J RES, SO, 0805, 0, 5%, 1/10W, METAL FILM
5 1 Y2 24.576 MHz XTALHC49PAD EPSON CRYSTAL, 24.576MHz, H49-US TYPE, Fund
Mode Par Res
6 1 U5 MC78L05ACD VREG SO8 MOTOROLA MC78L05ACD 5V POS. VOLT. REG., 100ma
Item Qty Reference Value Type PCB-Footprint Mnfr Part Number Description
• Notes •