SM8706A Datasheet, PDF (6/8 Pages) Nippon Precision Circuits Inc – Clock Generator for DVD Players

SM8706A
Sampling Frequency and Output Clock Frequency
The SM8706A sampling frequency fs can be switched between 44.1kHz when FSEL (pin 14) is LOW, and
48kHz when FSEL is HIGH. The audio outputs (AO1 and AO2) are a 384fs and 768fs frequency clock, respec-
tively, where fs is determined by the setting on FSEL. In addition, the signal processor outputs (SO1 and SO2)
are a 16.9344MHz and 33.8688MHz frequency clock, respectively, derived from the master clock. The video
outputs (MO1 and MO2) are a 27MHz and 54MHz frequency clock, respectively, derived from the master
clock.
When CE (Pin16) is HIGH, the chip is enabled. When LOW, the chip is disabled. When disabled, all output go
LOW and all internal circuits stop operating. When CE goes LOW to HIGH, the chip moves from disabled to
enabled, the time taken until the output frequency clocks stabilize is a maximum of 5ms.
The SM8706A output clock frequencies that can be selected is shown in Table 1. The output clock response
timing relative to the CE setting is shown in Figure 5.
Table 1. Sampling frequency and output clock frequency (36.8640MHz master clock frequency)
FSEL
(Pin 14)
LOW
HIGH
LOW
HIGH
Sampling
frequency
fs [kHz]
44.1
48
44.1
48
CE
(Pin 16)
H
L
AO1
(Pin 9)
16.9344
18.4320
L
AO2
(Pin 10)
33.8688
36.8640
Output clock frequency [MHz]
SO1
(Pin 13)
SO2
(Pin 15)
16.9344
33.8688
16.9344
33.8688
MO1
(Pin 3)
27.0000
27.0000
L
L
L
L
MO2
(Pin 4)
54.0000
54.0000
L
CE
AO1/AO2
SO1/SO2
MO1/MO2
5ms
(max)
Figure 5. CE switching response
NIPPON PRECISION CIRCUITS—6