Cirrus Logic CRD4297-1 AMR, Product Data Book

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4 DS242RD1B1
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 Common 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 k
Ω
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 overview
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