8x300 design guide - Al Kossow's Bitsavers - Trailing-Edge

BIPOLAR LSI DIVISION
CLOCK REQUIREMENTS
Crystal Osciliator.The on-chip crystal oscillator circuit is
designed for operation using an external series-resonant
quartz crystal; alternately the crystal oscillator can be
driven with complementary outputs pf a pulse generator or
interfaced to a master clock source via TTL logic-see
accompanying circuits. When a crystal is used, the on-chip
oscillator operates at the resonant frequency (f,) of the
crystal; the crystal connects to the 8X330 via pins 3 (X1) and
2 (X21. The lead lengths of the crystal should be approximately
equal and as short as possible; also, avoid close
proximity to all potential noise sources. The crystal should
be hermetically sealed (He type can) and have the following
electrical characteristics:
Type: Fundamental mode, series resonant
Impedance at Fundamental: 35-ohms maximum
Impedance at Harmonics and Spurs: 50-ohms minimum
CLOCKING XTAL OSC WITH PULSE GEN
PULSE
GENERATOR
+
PULSE GEN CHAR:
ZOUT = SOli
VOUT = o--2V
RISETIME,s 10'1SEC
SKEW ,s 10'1SEC
COMPLEMENTARY OUTPUTS
>
J SOli
~ ~ SOli
- ~
3 (X1)
2 (X2)
8X330
CLOCKING XTAL OSC WITH OPEN-COLLECTOR
TTL
When the crystal oscillator is externally-driven, typical
waveforms are as follows:
CLOCK
3 (X1)
2 (X2)
8X330
X1_
X2 _
, \,---/
1 1
VI 'SKEW ~ \, I
--J: ~ ....---------':
I I
I· 'PW---.....•
.... 1 1
1 1
1.1---------FREQ ....
--------~. I
FREQUENCY = 8 MHz (TYP)/16 MHz (MAX)
'PW = 50% (TYP)
'SKEW ,s 10'1SEC
16
Si!lDOliCS