PRELIMINARY DATA SHEET
VDP 31xxB
Recommended Crystal Characteristics, continued
Symbol
Parameter
Min.
Typ.
Max.
Unit
Load Capacitance Recommendation
1)
C
Lext
External Load Capacitance
from pins to Ground
–
3.3
–
pF
(pin names: Xtal1 Xtal2)
2)
DCO Characteristics
C
Effective Load Capacitance @ min.
DCO-Position, Code 0,
3.6
4.3
5
pF
pF
ICLoadmin
C
Effective Load Capacitance Range,
DCO Codes from 0..255
11.7
12.7
13.7
ICLoadrng
1) Remarks on defining the External Load Capacitance:
External capacitors at each crystal pin to ground are required. They are necessary to tune the effective load capacitance of
the PCBs to the required load capacitance CL of the crystal. The higher the capacitors, the lower the clock frequency re-
sults. The nominal free running frequency should match fp MHz. Due to different layouts of customer PCBs the matching
capacitor size should be determined in the application. The suggested value is a figure based on experience with various
PCB layouts.
Tuning condition: Code DVCO Register = –720
2) Remarks on Pulling Range of DCO:
The pulling range of the DCO is a function of the used crystal and effective load capacitance of the IC (CICLoad +CLoadBoard).
The resulting frequency fL with an effective load capacitance of CLeff = CICLoad + CLoadBoard is
1 + 0.5 * [ C1 / (C0 + CLeff ) ]
fL = fP * –––––––––––––––––––––––
1 + 0.5 * [ C1 / (C0 + CL ) ]
4.6.4. Characteristics
at T = 0 to 65 °C, V
= 4.75 to 5.25 V, f = 20.25 MHz for min./max. values
A
SUPD/F/O
at T = 60 °C, V
= 5 V, f = 20.25 MHz for typical values
C
SUPD/F/O
Symbol
Parameter
Current Consumption
Pin Name
Min.
–
Typ.
38
Max.
Unit
mA
mA
mA
mA
W
I
I
I
I
V
SUPF
V
SUPD
V
SUPO
V
STDBY
–
VSUPF
VSUPD
VSUPO
VSTDBY
Current Consumption
–
123
64
–
Current Consumption
–
–
Current Consumption
–
3.3
1145
–
–
P
TOT
Total Power Dissipation
Input / Output Leakage Current
–
1200
1
IL
All I/O Pins
–1
mA
Micronas
55
MICRONAS [ MICRONAS ]
