TSC2102IDA datasheet(25/54 Pages) TI

25 / 54 page

TSC2102

SLAS379A− APRIL 2003 − REVISED JUNE 2004

www.ti.com

Example 2:

For MCLK = 12 MHz and Fsref = 48.0 kHz

P = 1, K = 8.192

⇒ J = 8, D = 1920

Digital Audio Processing

The DAC channel consists of optional filters for de-emphasis and bass, treble, midrange level adjustment, or speaker

equalization. The de-emphasis function is only available for sample rates of 32 kHz, 44.1 kHz, and 48 kHz. The transfer

function consists of a pole with time constant of 50

µs and a zero with time constant of 15 µs. Frequency response plots

are given in the Audio Codec Filter Frequency Responses section of this data sheet.

The DAC digital effects processing block also includes a fourth order digital IIR filter with programmable coefficients (one

set per channel). The filter is implemented as cascade of two biquad sections with frequency response given by:

) 2

z*1

) N2

z*2

32768

* 2

z*1

* D2

z*2

) 2

z*1

) N5

z*2

32768

* 2

z*1

* D5

z*2

The N and D coefficients are fully programmable, and the entire filter can be enabled or bypassed. The coefficients for this

filter implement a variety of sound effects with bass boost or treble boost as the most commonly used in portable audio

applications. The default N and D coefficients in the part are given by:

N0 = N3 = 27619

D1 = D4 = 32131

N1 = N4 = −27034

D2 = D5 = −31506

N2 = N5 = 26461

and implement a shelving filter with 0-dB gain from dc to approximately 150 Hz, at which point it rolls off to 3-dB attenuation

for higher frequency signals, thus giving a 3-dB boost to signals below 150 Hz. The N and D coefficients are represented

by 16-bit twos complement numbers with values ranging from 32767 to −32768. Frequency response plots are given in

the Audio Codec Filter Frequency Responses section of this data sheet.

Interpolation Filter

The interpolation filter upsamples the output of the digital audio processing block by the required oversampling ratio. It

provides a linear phase output with a group delay of 21/Fs.

In addition, the digital interpolation filter provides enhanced image filtering to reduce signal images caused by the

upsampling process that are below 20 kHz. For example, upsampling an 8-kHz signal produces signal images at multiples

of 8 kHz, i.e., 8 kHz, 16 kHz, 24 kHz, etc. The images at 8 kHz and 16 kHz are below 20 kHz and still audible to the listener,

therefore, they must be filtered heavily to maintain a good quality output. The interpolation filter is designed to maintain at

least 65-dB rejection of images that land below 7.455 Fs. Passband ripple for all sample-rate cases (from 20 Hz to 0.45 Fs)

±0.06 dB maximum

Delta-Sigma DAC

The

audio

digital-to-analog

converter

incorporates

third

order

multibit

delta-sigma

modulator

with

768/512/384/256/192/128 times oversampling followed by an analog reconstruction filter. The DAC provides

high-resolution, low-noise performance, using oversampling and noise shaping techniques. The analog reconstruction

filter design consists of a 6 tap analog FIR filter followed by a continuous time RC filter. The analog FIR operates at 6.144

MHz (128x48 kHz, for Fsref of 48 kHz) or at 5.6448 MHz (128x44.1 kHz, for Fsref of 44.1 kHz). The DAC analog

performance can be degraded by excessive clock jitter on the MCLK input. Therefore, care must be taken to keep jitter on

this clock to a minimum.

TSC2102IDA Datasheet(PDF) 25 Page - Texas Instruments

TSC2102IDA Datasheet(HTML) 25 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

Datasheet Download

Link URL