Cirrus Logic CRD4299-1 AVR - Manual (Page 5)

CRD4299-1 AMR
DS319RD1A1 5
MC78L05 regulates the AMR +12 V supply down
to provide a clean +5 V analog supply for the
CS4299. The MC78L05 regulator can provide ade-
quate 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 capac-
itor to the analog ground plane. The analog section
contains the components for a headphone amplifi-
er. 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 in-
puts 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
• 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 im-
pedances greater than 10 k
Ω
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
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 2-
pin dynamic microphones
2.4.5 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 standards and ATAPI.
• Maximum input level: 2 Vrms
• Pseudo differential input using the CD Com-
mon pin as the ground
• 0.1 inch connector wired as:
- Pin 1 : Left Channel
- Pin 2 : Common return