
21
4109LS–8051–02/08
AT8xC51SND1C
7.2.2
A to D Converter
Table 18. A to D Converter DC Characteristics
VDD = 2.7 to 3.3 V, TA = -40 to +85°C
7.2.3
Oscillator & Crystal
7.2.3.1
Schematic
Figure 7-4.
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.
7.2.3.2
Parameters
Table 19. Oscillator & Crystal Characteristics
VDD = 2.7 to 3.3 V, TA = -40 to +85°C
Symbol
Parameter
Min
Typ
Max
Units
Test Conditions
AV
DD
Analog Supply Voltage
2.7
3.3
V
AIDD
Analog Operating Supply Current
600
A
AV
DD= 3.3V
AIN1:0= 0 to AVDD
ADEN= 1
AIPD
Analog Standby Current
2
A
AV
DD= 3.3V
ADEN= 0 or PD= 1
AV
IN
Analog Input Voltage
AV
SS
AV
DD
V
AVREF
Reference Voltage
AREFN
A
REFP
AVSS
2.4
AV
DD
V
R
REF
AREF Input Resistance
10
30
K
T
A= 25°C
C
IA
Analog Input capacitance
10
pF
T
A= 25°C
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
W
F
Crystal Frequency
20
MHz
RS
Crystal Series Resistance
40
CS
Crystal Shunt Capacitance
6
pF