CSR8615 View Datasheet(PDF) - Unspecified
Part Name
Description
MFG CO.
'CSR8615' PDF : 114 Pages View PDF
9.2.2 ADC
Figure 9.2 shows the CSR8615 QFN consists of 2 high-quality ADCs:
â– Each ADC has a second-order Sigma-Delta converter.
â– Each ADC is a separate channel with identical functionality.
â– There are 2 gain stages for each channel, 1 of which is an analogue gain stage and the other is a digital
gain stage, see Section 9.2.4.
9.2.3 ADC Sample Rate Selection
3 Each ADC supports the following pre-defined sample rates, although other rates are programmable, e.g. 40kHz:
01 â– 8kHz
, 2 â– 11.025kHz
16 â– 16kHz
ber â– 22.050kHz
m â– 24kHz
pte â– 32kHz
Se â– 44.1kHz
y, â– 48kHz
onda 9.2.4 ADC Audio Input Gain
n - M ADC Pre-amplifier
.c and ADC Analogue Gain:
m -3dB to 42dB in 3dB steps
ADC Digital Gain:
-24dB to 21.5dB in alternating
2.5dB and 3dB steps
mm.co ADC Pre-amplifier:
ADC Analogue Gain:
o 0dB, 9dB, 21dB and 30dB -3dB to 12dB in 3dB steps
pachec Audio Input
To Digital Codec
es Tsao - a System Gain = ADC Pre-amplifier + ADC Analogue Gain + ADC Digital Gain
for jam Figure 9.3: Audio Input Gain
red 9.2.5 ADC Pre-amplifier and ADC Analogue Gain
Prepa CSR8615 QFN has an analogue gain stage based on an ADC pre-amplifier and ADC analogue amplifier:
â– The ADC pre-amplifier has 4 gain settings: 0dB, 9dB, 21dB and 30dB
â– The ADC analogue amplifier gain is -3dB to 12dB in 3dB steps
â– The overall analogue gain for the pre-amplifier and analogue amplifier is -3dB to 42dB in 3dB steps, see
Figure 9.3
â– At mid to high gain levels it acts as a microphone pre-amplifier, see Section 9.2.13
â– At low gain levels it acts as an audio line level amplifier
9.2.6 ADC Digital Gain
A digital gain stage inside the ADC varies from -24dB to 21.5dB, see Table 9.2. There is also a fine gain interface
with a 9-bit gain setting allowing gain changes in 1/32 steps, for more information contact CSR.
The firmware controls the audio input gain.
Pre-production Information
© Cambridge Silicon Radio Limited 2013
Confidential Information - This Material is Subject to CSR's Non-disclosure Agreement
Page 40 of 114
CS-303726-DSP3
www.csr.com
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