SLAS763C August 2012 – October 2018 PCM5121 , PCM5122
PRODUCTION DATA.
The PCM512x requires a system clock to operate the digital interpolation filters and advanced segment DAC modulators. The system clock is applied at the SCK input and supports up to 50 MHz. The PCM512x system-clock detection circuit automatically senses the system-clock frequency. Common audio sampling frequencies in the bands of 8 kHz, 16 kHz, (32 kHz - 44.1 kHz - 48 kHz), (88.2kHz - 96kHz), (176.4 kHz - 192 kHz), and 384 kHz with ±4% tolerance are supported. Values in the parentheses are grouped when detected, (for example, 88.2 kHZ and 96 kHz are detected as double rate, and 32 kHz, 44.1 kHz and 48 kHz are detected as single rate.)
In the presence of a valid bit SCK, BCK and LRCK in software mode, the device will auto-configure the clock tree and PLL to drive the miniDSP as required.
The sampling frequency detector sets the clock for the digital filter, Delta Sigma Modulator (DSM) and the Negative Charge Pump (NCP) automatically. Table 32 shows examples of system clock frequencies for common audio sampling rates.
SCK rates that are not common to standard audio clocks, between 1 MHz and 50 MHz, are only supported in software mode by configuring various PLL and clock-divider registers. This programmability allows the device to become a clock master and drive the host serial port with LRCK and BCK, from a non-audio related clock (for example, using 12 MHz to generate 44.1 kHz [LRCK] and 2.8224 MHz [BCK]).
SAMPLING FREQUENCY | SYSTEM CLOCK FREQUENCY (fSCK) (MHz) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
64 fS | 128 fS | 192 fS | 256 fS | 384 fS | 512 fS | 768 fS | 1024 fS | 1152 fS | 1536 fS | 2048 fS | 3072 fS | |
8 kHz | –(1) | 1.024(2) | 1.536(2) | 2.048 | 3.072 | 4.096 | 6.144 | 8.192 | 9.216 | 12.288 | 16.384 | 24.576 |
16 kHz | –(1) | 2.048(2) | 3.072(2) | 4.096 | 6.144 | 8.192 | 12.288 | 16.384 | 18.432 | 24.576 | 36.864 | 49.152 |
32 kHz | –(1) | 4.096(2) | 6.144(2) | 8.192 | 12.288 | 16.384 | 24.576 | 32.768 | 36.864 | 49.152 | –(1) | –(1) |
44.1 kHz | –(1) | 5.6488(2) | 8.4672(2) | 11.2896 | 16.9344 | 22.5792 | 33.8688 | 45.1584 | –(1) | –(1) | –(1) | –(1) |
48 kHz | –(1) | 6.144(2) | 9.216(2) | 12.288 | 18.432 | 24.576 | 36.864 | 49.152 | –(1) | –(1) | –(1) | –(1) |
88.2 kHz | –(1) | 11.2896(2) | 16.9344 | 22.5792 | 33.8688 | 45.1584 | –(1) | –(1) | –(1) | –(1) | –(1) | –(1) |
96 kHz | –(1) | 12.288(2) | 18.432 | 24.576 | 36.864 | 49.152 | –(1) | –(1) | –(1) | –(1) | –(1) | –(1) |
176.4 kHz | –(1) | 22.579 | 33.8688 | 45.1584 | –(1) | –(1) | –(1) | –(1) | –(1) | –(1) | –(1) | –(1) |
192 kHz | –(1) | 24.576 | 36.864 | 49.152 | –(1) | –(1) | –(1) | –(1) | –(1) | –(1) | –(1) | –(1) |
384 kHz | 24.576 | 49.152 | –(1) | –(1) | –(1) | –(1) | –(1) | –(1) | –(1) | –(1) | –(1) | –(1) |
See for clock timing requirements.