ST7920 Ver la hoja de datos (PDF) - Unspecified
Número de pieza
componentes Descripción
Lista de partido
ST7920 Datasheet PDF : 49 Pages
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ST7920
Pin Description (continued)
Name
CAP3M
CAP1P
CAP1M
CAP2M
XOFF
CAP2P
C[33]
VD2
CLK
TT1
TT2
No. I/O
34
35
36
I/O
38
32
O
37
―
72
O
39
I
4
5
I
6
Connects to
Description
Capacitors
Capacitor pins for voltage doubler
Voltage ≦ 7V.
―
―
―
Reference voltage
―
―
―
Reserved (no connection).
Reserved (no connection).
Reserved (no connection).
Voltage doubler reference voltage.
If use internal voltage doubler, please
make sure that:
l VD2 ≦ 3.5V or
l VOUT ≦ 7V and CAP3M ≦ 7V.
For CGROM/HCGROM checksum.
Refer to checksum application.
Note:
1. 7V>=VOUT>=V0>=V1>=V2>=V3>=V4 must be maintained
2. Two clock options: As shown below.
OSC1
OSC2
R
R=33K (VDD=5.0V)
R=18K (VDD=2.7V)
Clock input
OSC1
OSC2
800
700
600
500
400
300
200
100
0
5
External Resistor vs. Current
(VDD=5V)
15 25 40 60 80 100
Resistor(K)
External Resistor vs. Frequency
(VDD=5V)
900
800
700
600
500
400
300
200
100
0
5
15 25 40 60 80 100
Res is tor(K)
3. When using voltage doubler (VOUT), it is recommended that the sum of those divide resistors (R1~R5) should be larger than 20K Ohm.
So that the voltage doubler can provide sufficient power.
V4.0
8/49
2008/08/18
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