SM8703 View Datasheet(PDF) - Nippon Precision Circuits

Part Name

Description

Manufacturer

SM8703

Clock Generator for MPEG2 System

Nippon Precision Circuits  

SM8703AV

Sampling Frequency and Output Clock Frequency

The SM8703AV generates several output clocks from the 27 MHz master clock, with frequencies of 384fs

(SO2), 512fs (SO3, SO4) and 768fs (SO5), where fs is the sampling frequency selected by external control

inputs. SO1 outputs 33.8688 MHz clock. The supported sampling frequencies are 44.1 kHz and 48 kHz,

selected by the sampling frequency select pin (FSEL). The generated frequencies are shown in table 1.

Table 1. Sampling frequency and output clock frequency

FSEL

LOW

HIGH

Sampling

frequency fs

44.1 kHz

48 kHz

SO1

33.8688

33.8688

Output clock frequency (MHz)

SO2

SO3, SO4

16.9344

22.5792

18.4320

24.5760

SO5

33.8688

36.8640

Enable/Disable control

3 wire serial interface is available by using MCK(pin4), MLEN(pin5) and MDT(pin23:FSEL common) pins as

serial mode. At the serial control mode, each enable (fixed as "LOW" at disable) of output frequency can be set

to stop unnecessary outputs.

MCK

FSEL/MDT D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

MLEN

Figure 3. Serial control format

16-bit mode resister (MREG) construction in Figure 4. The name and function of each bit are shown in Table 2

and 3. Set the mode-resister D15-D10 as "011100" in the serial control.

MREG 0 1 1 1 0 0 RSV CE5 CE4 CE3 CE2 CE1 RSV RSV RSV RSV

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

Figure 4. Mode resister construction

Note: RSV is fixed as LOW .

NIPPON PRECISION CIRCUITS—8

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