Datasheet

184
AT8xC51SND1C
4109E–8051–06/03
A to D Converter
Table 155. A to D Converter DC Characteristics
V
DD
= 2.7 to 3.3 V, T
A
= -40 to +85°C
Oscillator & Crystal
Schematic Figure 139. 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 spe-
cial cases (max 10 pF). X1 and X2 may not be used to drive other circuits.
Parameters Table 156. Oscillator & Crystal Characteristics
V
DD
= 2.7 to 3.3 V, T
A
= -40 to +85°C
Symbol Parameter Min Typ Max Units Test Conditions
AV
DD
Analog Supply Voltage 2.7 3.3 V
AI
DD
Analog Operating Supply
Current
600 µA
AV
DD
= 3.3V
AIN1:0= 0 to AV
DD
ADEN= 1
AI
PD
Analog Standby Current 2 µA
AV
DD
= 3.3V
ADEN= 0 or PD= 1
AV
IN
Analog Input Voltage AV
SS
AV
DD
V
AV
REF
Reference Voltage
A
REFN
A
REFP
AV
SS
2.4 AV
DD
V
R
REF
AREF Input Resistance 10 30 KΩ 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 µW
F Crystal Frequency 20 MHz
RS Crystal Series Resistance 40 Ω
CS Crystal Shunt Capacitance 6 pF