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PCM1803A

SLES142B – JUNE 2005 – REVISED JULY 2016

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Table 2. System Clock Timing Requirements

PARAMETER

MIN

MAX

UNIT

tw(SCKH)

System clock pulse duration, HIGH

8

ns

tw(SCKL)

System clock pulse duration, LOW

8

ns

The quality of the system clock can influence the dynamic performance, because the PCM1803A operates based

on a system clock. Therefore, it may be required to consider the system-clock duty, jitter, and the time difference

between system-clock transition and BCK or LRCK transition in the slave mode.

7.4 Device Functional Modes

7.4.1 Serial Audio Data Interface

The PCM1803A interfaces the audio system through BCK (pin 11), LRCK (pin 10), and DOUT (pin 12).

7.4.1.1 Interface Mode

The PCM1803A supports master mode and slave mode as interface modes, and they are selected by MODE1

(pin 20) and MODE0 (pin 19) as shown in Table 3.

In master mode, the PCM1803A provides the timing of serial audio data communications between the

PCM1803A and the digital audio processor or external circuit. While in slave mode, the PCM1803A receives the

timing for data transfers from an external controller.

Table 3. Interface Mode

MODE1

MODE0

INTERFACE MODE

0

0

Slave mode (256 fS, 384 fS, 512 fS, 768 fS)

0

1

Master mode (512 fS)

1

0

Master mode (384 fS)

1

1

Master mode (256 fS)

7.4.1.1.1

Master Mode

In master mode, BCK and LRCK work as output pins, and these pins are controlled by timing, which is generated

in the clock circuit of the PCM1803A. The frequency of BCK is fixed at LRCK × 64. The 768-fS system clock is

not available in master mode.

7.4.1.1.2

Slave Mode

In slave mode, BCK and LRCK work as input pins. The PCM1803A accepts the 64-BCK/LRCK or 48-BCK/LRCK

format (only for 384 fS and 768 fS system clocks), not the 32-BCK/LRCK format.

7.4.1.2 Data Format

The PCM1803A supports four audio data formats in both master and slave modes, and the data formats are

selected by FMT1 (pin 18) and FMT0 (pin 17) as shown in Table 4. Figure 19 illustrates the data formats in slave

and master modes.

Table 4. Data Formats

FORMAT

FMT1

FMT0

DESCRIPTION

0

0

0

Left-justified, 24-bit

1

0

1

I2S, 24-bit

2

1

0

Right-justified, 24-bit

3

1

1

Right-justified, 20-bit