TLV320AIC31_07 Datasheet, PDF (21/77 Pages) Burr-Brown (TI) – LOW POWER STEREO AUDIO CODEC FOR PORTABLE AUDIO/TELEPHONY

TLV320AIC31
www.ti.com
SLAS497A – AUGUST 2006 – REVISED SEPTERMBER 2006
OVERVIEW (continued)
AUDIO DATA CONVERTERS
The TLV320AIC31 supports the following standard audio sampling rates: 8 kHz, 11.025 kHz, 12 kHz, 16 kHz,
22.05 kHz, 24 kHz, 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, and 96 kHz. The converters can also operate at
different sampling rates in various combinations, which are described further below.
The data converters are based on the concept of an Fsref rate that is used internal to the part, and it is related
to the actual sampling rates of the converters through a series of ratios. For typical sampling rates, Fsref will be
either 44.1 kHz or 48 kHz, although it can realistically be set over a wider range of rates up to 53 kHz, with
additional restrictions applying if the PLL is used. This concept is used to set the sampling rates of the ADC and
DAC, and also to enable high quality playback of low sampling rate data, without high frequency audible noise
being generated.
The sampling rate of the ADC and DAC can be set to Fsref/NDAC or 2×Fsref/NDAC, with NDAC being 1, 1.5, 2,
2.5, 3, 3.5, 4, 4.5, 5, 5.5, or 6.
AUDIO CLOCK GENERATION
The audio converters in the TLV320AIC31 need an internal audio master clock at a frequency of 256×Fsref,
which can be obtained in a variety of manners from an external clock signal applied to the device.
A more detailed diagram of the audio clock section of the TLV320AIC31 is shown in Figure 23.
MCLK BCLK
CLKDIV_CLKIN
PLL_CLKIN
CLKDIV_IN
PLL_IN
Q=2,3,…..,16,17
K = J.D
J = 1,2,3,…..,62,63
2/Q
K*R/P
D= 0000,0001,….,9998,9999
R= 1,2,3,4,….,15,16
P= 1,2,….,7,8
CLKDIV_OUT
PLL_OUT
1/8
PLLDIV_OUT
CODEC_CLKIN
CODEC_CLK=256*Fsref
CODEC
DAC_FS
ADC_FS
WCLK= Fsref/Ndac
Ndac=1,1.5,2,…..,5.5,6
DAC DRA => Ndac = 0.5
Figure 23. Audio Clock Generation Processing
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