CS4298 Datasheet, PDF (46/52 Pages) Cirrus Logic – SoundFusion Audio/Modem Codec 97 (AMC 97)

CS4298
VIDEO_L and VIDEO_R - Analog Video Audio Source, Inputs
These inputs form a stereo input pair to the CS4298. It is intended to be used for the audio
signal output of a video device. The maximum allowable input is 1 V_RMS (sinusoidal). These
inputs are internally biased at the Vrefout voltage reference. AC coupling to external circuitry
is required. If these inputs are not used, they should both be connected to the Vrefout pin or
both AC coupled, with separate AC coupling caps, to analog ground.
AUX_L and AUX_R - Analog Auxiliary Source, Inputs
These inputs form a stereo input pair to the CS4298. The maximum allowable input is 1 V_RMS
(sinusoidal). These inputs are internally biased at the Vrefout voltage reference. AC coupling to
external circuitry is required. If these inputs are not used, they should both be connected to the
Vrefout pin or both AC coupled, with separate AC coupling caps, to analog ground.
LINE_OUT_L and LINE_OUT_R - Analog Line Level Outputs
These signals are analog outputs from the stereo output mixer. The full scale output voltage for
output is nominally 1 V_RMS and is internally biased at the Vrefout voltage reference. It is
required to either AC couple these pins to external circuitry or DC couple them to a buffer op-
amp biased at the Vrefout voltage. These pins need a 680 pF NPO capacitor attached to analog
ground.
ALT_LINE_OUT_L and ALT_LINE_OUT_R - Analog Alternate Line Level Outputs
These signals are analog outputs from the stereo output mixer. The full scale output voltage for
each output is nominally 1 V_RMS and is internally biased at the Vrefout voltage reference. It is
required to either AC couple these pins to external circuitry or DC couple them to a buffer op-
amp biased at the Vrefout voltage. These pins need a 680 pF NPO capacitor attached to analog
ground.
8.3 Filter and Reference Pins
REFFLT - Internal Reference Voltage, Input
This is the voltage reference used internal to the part. A 0.1 µF and a 1 µF (must not be larger
than 1 µF) capacitor with short, wide traces must be connected to this pin. No other
connections should be made to this pin.
Vrefout - Voltage Reference, Output
All analog inputs and outputs are centered around Vrefout which is nominally 2.2 Volts. This
pin may be used to level shift external circuitry, however any external loading should be
buffered.
AFLT1 - Left Channel Antialiasing Filter Input
This pin needs a 390 pF NPO capacitor attached to analog ground.
AFLT2 - Right Channel Antialiasing Filter Input
This pin needs a 390 pF NPO capacitor attached to analog ground.
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