YMF721 Datasheet, PDF (22/41 Pages) LSI Computer Systems – FM + Wavetable Synthesizer LSI

YMF721
7-4. Others
Power Supply
It is recommended to install a line noise filter in the YMF721 (OPL4-ML2). Be sure to install 0.1uF
ceramic capacitor between each of VDD pins and VSS pins as close to the pins as possible, especially
the pin No. 63 (VDD).
5V/3V
When operating YMF721 (OPL4-ML2) with 5 V, 5V/3V pin must be pulled up. When operating it
with 3.3 V, set the pin to "L".
XI, XO
YMF721 (OPL4-ML2) requires the clock frequency of 33.8688 MHz. This signal can be supplied
from the system or from the self-oscillation circuit connected with crystal oscillator
Yamaha recommends either of the following two types of parallel resonance type oscillator
made by Daishinku Co., Ltd.
(i) 3rd Overtone Type
AT-49, SMD-49 : R=5.6K, c₁=c₂=10pF
(ii) Fundamental Type
AT-49, SMD-49 : R=1M, c₁=c₂=5pF
Use of the Crystal oscillator with frequency deviation within 100 ppm is recommended. Length of
wiring lead from XI and XO pin to each component (crystal, resistor and capacitor) should be 0.5
inch or less respectively and the circuit pattern should be shielded on its periphery to minimize effect
on the peripheral devices.
YMF721(OPL4-ML2)
99
XI
100
XO
33.8688MHz
R
c₁
c₂
Since YMF721 (OPL4-ML2) is able to use power down mode, the power consumption can be
minimized when generation of the clock signal is discontinued during this mode.
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July 10, 1997