SAA8200HL Datasheet, PDF (34/71 Pages) NXP Semiconductors – Ensation Base integrated wireless audio baseband

Philips Semiconductors
SAA8200HL
Ensation Base integrated wireless audio baseband
7.18 Audio configuration
The audio configuration block gives access to the following system settings:
• I²S-bus input/output format settings
• Status of SPDIF module
• SPDIF interrupt request
• SDAC control and status registers
• SADC control and status registers
• Interrupt request to EPICS7B; with automatically clearing register
• Power-down of the multi-channel 10-bit control ADC
• DC-to-DC converter output voltage settings
• DC-to-DC clock-stable indicator.
7.19 Audio input
7.19.1 ADC analog front-end
The analog front-end of the ADC consists of one stereo ADC with a selector in front of it.
Using this selector one can either select the microphone input with the microphone
amplifier (LNA) with a fixed 30 dB gain or the line input. The microphone input as well as
the line inputs have a Programmable Gain Amplifier (PGA) that allows gain control from
0 dB to 24 dB in steps of 3 dB.
The input impedance of the PGA (line in) is 12 kΩ, for the LNA this is 5 kΩ.
7.19.1.1 Applications and Power-down modes
The following Power-down and functional modes are supported:
• Power-down mode in which the current consumption is very low (only leakage
currents). In this mode there is no reference voltage at the line input.
• Line-in mode, in which the PGA can be used.
• Microphone mode in which the rest of the non-used PGAs and ADCs are powered
down. In this mode the mono microphone signal can be sent to both left and right
input of the decimation filter. This is done with a separate multiplexer in front of the
decimation input. This multiplexer is controlled by bit SEL_MIC in the I²C-bus control
interface.
• Mixed PGA and LNA mode with one line-in and one microphone input.
mic
LNA
PGA
SDC
left
PGA
SDC
right
PGA
SDC
SAA8200HL_2
Preliminary data sheet
Fig 6. Analog front-end
Rev. 02 — 17 October 2005
ADC
left_out
ADC
right_out
001aab455
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
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