Datasheet

210
4341H–MP3–10/07
AT8xC51SND2C/MP3B
24.2.2 Oscillator & Crystal
24.2.2.1 Schematic
Figure 24-4. Crystal Connection
Note: For operation with most standard crystals, no external components are needed on X1 and X2. It
may be necessary to add external capacitors on X1 and X2 to ground in special cases (max 10
pF). X1 and X2 may not be used to drive other circuits.
24.2.2.2 Parameters
Table 24-3. Oscillator & Crystal Characteristics
V
DD
= 2.7 to 3.3 V, T
A
= -40 to +85°C
24.2.3 Phase Lock Loop
24.2.3.1 Schematic
Figure 24-5. PLL Filter Connection
24.2.3.2 Parameters
Table 24-4. PLL Filter Characteristics
VSS
X1
X2
Q
C1
C2
Symbol Parameter Min Typ Max Unit
C
X1
Internal Capacitance (X1 - VSS) 10 pF
C
X2
Internal Capacitance (X2 - VSS) 10 pF
C
L
Equivalent Load Capacitance (X1 - X2) 5 pF
DL Drive Level 50 µ W
F Crystal Frequency 20 MHz
RS Crystal Series Resistance 40 Ω
CS Crystal Shunt Capacitance 6 pF
VSS
FILT
R
C1
C2
VSS