Datasheet

Oscillator
Technical Data MC68HC912D60A — Rev. 3.1
180 Oscillator Freescale Semiconductor
Figure 12-2. MC68HC912D60C Colpitts Oscillator Architecture
There are the following primary differences between the previous (’A’)
and new (’C’) Colpitts oscillator configurations:
• Hysteresis was added to the clock input buffer to reduce sensitivity
to noise
• Internal parasitics were reduced from EXTAL to VSS to increase
oscillator gain margin.
ALC
+
-
OTA
+
-
CFLT
RFLT
EN
BIAS
Resonator
C
X-EX
C
X-VSS
BUF
RFLT
CFLT
2
GM
EXTAL XTAL
RESD