At8xc51snd1c – Rainbow Electronics AT89C51SND1C User Manual
Page 184
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
µ
A
AV
DD
= 3.3V
AIN1:0= 0 to AV
DD
ADEN= 1
AI
PD
Analog Standby Current
2
µ
A
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
K
Ω
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
µ
W
F
Crystal Frequency
20
MHz
RS
Crystal Series Resistance
40
Ω
CS
Crystal Shunt Capacitance
6
pF