Datasheet

0
–20
–40
–60
–80
–100
–120
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Magnitude dB
–
Frequency Normalized With Respect to f
S
ADC Channel Response for Decimation Filter C
(Red line corresponds to –60 dB)
ADC Data Interface
Digital Microphone Function
TLV320ADC3101
SLAS553A – NOVEMBER 2008 – REVISED SEPTEMBER 2009 ...................................................................................................................................... www.ti.com
Decimation Filter C
Filter type C along with an AOSR of 32 is specially designed for 192-ksps operation of the ADC. The pass band,
which extends up to 0.11 × f
S
(corresponds to 21 kHz), is suited for audio applications.
Table 12. Specifications for ADC Decimation Filter C
Parameter Condition Value (Typical) Unit
Filter gain from 0 to 0.11 f
S
0 – 0.11 f
S
± 0.033 dB
Filter gain from 0.28 f
S
to 16 f
S
0.28 f – 16 f
S
– 60 dB
Filter group delay 11/f
S
s
Pass-band ripple, 8 ksps 0 – 0.11 f
S
0.033 dB
Pass-band ripple, 44.18 ksps 0 – 0.11 f
S
0.033 dB
Pass-band ripple, 48 ksps 0 – 0.11 f
S
0.032 dB
Pass-band ripple, 96 ksps 0 – 0.11 f
S
0.032 dB
Pass-band ripple, 192 ksps 0 – 20 kHz 0.086 dB
Figure 46. ADC Decimation Filter C, Frequency Response
The decimation filter and signal processing block in the ADC channel passes 32-bit data words to the audio
serial interface once every frame (WCLK). During each frame (WCLK), a pair of data words (for left and right
channels) is passed. The audio serial interface rounds the data to the required word length of the interface
before converting to serial data per the different modes for audio serial interface.
In addition to supporting analog microphones, the TLV320ADC3101 also interfaces to digital microphones.
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