ICS9120-49 Datasheet, PDF (2/5 Pages) Integrated Circuit Systems – Frequency Generator for CD-ROM Systems

ICS9120-49
Pin Configuration
8-Pin SOIC
External Components/Crystal Selection
The ICS9120-49 incorporates a crystal oscillator circuit de-signed
to provide 50% duty cycle over a range of operating conditions,
including the addition of external crystal load ca-pacitors to pins
X1 and X2. A parallel resonant 16.9344 MHz, 12pF load crystal is
recommended. A series resonant crystal or a parallel resonant
crystal specifying a different load can be used, but either will
result in frequencies which are slightly (up to 0.06%) different
from the ideal.
The crystal load capacitance can be increased by adding a capacitor
to each of the X1 and X2 pins and ground. This enables the use of
a crystal specifying a load greater than 12pF without changing the
output frequency.
Duty cycle is also maintained when using an external clock source
(connected to X1, X2 left unconnected) as long as the external
clock has good duty cycle.
Pin Descriptions for ICS9120-49
PIN
PIN
NUMBER NAME
1 X1
2 VDD
3 GND
4 CLK3
5 CLK2
6 CLK4
7 CLK1
8 X2
TYPE
DESCRIPTION
Input Crystal or external clock source. Has feedback bias for crystal.
Power +Power supply input.
Power Ground return for Pin 2.
Output 33.8688 MHz target output clock.
Output 22.5792 MHz target output clock.
Output 67.7376 MHz target output clock.
Output 16.9344 MHz reference clock buffered output.
Output Crystal output drive (leave this pin unconnected when using an external clock).
2