TAS5012

SLES006A – SEPTEMBER 2001 – REVISED DECEMBER 2001

8

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functional description (continued)

Initialization

Normal State

MUTE

VALID_L

5 ms max

10

µs Maximum

50–50 Duty Cycle

(P, M Complementary)

Inactive State

VALID_R

PWM Outputs

(P, M Complementary)

Figure 5. Mute Timing

double speed

Double-speed mode is used to support sampling rates of 88.2 kHz and 96 kHz. In order to put the TAS5012 in

double-speed mode with the device in normal operating conditions, the RESET pin must be held low while switching

the DBSPD pin high. After the RESET pin is brought high again, a reset sequence takes place. If the change is at

power up, a power-up sequence is originated.

quad speed

Quad-speed mode is used to support sampling rates of 176.4 kHz and 192 kHz. It is supported in slave mode only.

In order to put the TAS5012 in quad-speed mode, M_S and DBPSB pins are brought low. Quad-speed mode is then

automatically detected due to the fact that it is the only mode in which MCLK_IN is 128Fs. DEM_SEL must be set

to low when operating in the quad-speed mode.

de-emphasis filter

For audio sources that have been preemphasized, a precision 50-

µs/15-µs de-emphasis filter is provided to support

the sampling rates of 44.1 kHz and 48 kHz. Pins DEM_SEL and DEM_EN select the de-emphasis functions. See

Figure 6 for a graph showing the de-emphasis filtering characteristics. See Table 3 for de-emphasis selection.

0

–10

3.18 (50

µs)

10.6 (15

µs)

f – Frequency – kHz

De-emphasis

Figure 6. De-Emphasis Filter Characteristics