Table of Contents
Advertisement
TK-250
SEMICONDUCTOR
DATA
DTMF decoder: TC35305P/F(IC218)
• Internal bock diagram
Low-
group
I
I
bandpass
I
_I
I
J
_
Timer
control
circuit
-zërö
_u_~
crossing
detector
Reference
voltage
Internal
clock
- - i3änëJ;;äss - -
filter
r---
High-
group
bandpass
Timing
generator
circuit
Bias circuit
Dial tone
filter
ClK
@'
OSCE
0
IN
0
Vee
Vss
PD
• Pin function
Pin No.
Pin Name
1/0
Function
OT1
0
Reception data output terminal.
OE
= "
l"
; high impedance
OTO
0
OE
= "
H " ; output as the 4-bit code.
OE
I
01-04
3-state control terminal.
OE
= "
H " ; enable
OE
= "
l " ; high impedance
Vee
-
Power supply terminal (normally 5V)
PO
I
Enters standby mode when " l " is applied.
OSCE
I
Oscillation stage control terminal.
IN
I
Signal input terminal.
Vss
-
Power supply terminaL(Nrmally OV)
X2
,0
3.579545MHz
quartz crystaL
X1
I
3.579545MHz
quartz crystaL
Connected to VOO when using an extemal clock.
ClK
1/0
OSCE
= "
H " ; external cloek output
OSCE
= "
H " ; external cloek input
OFOV
0
Becomes " H " when an effective tone pair continues for the stipulated period and is detected.
OT3
0
Reception data output terminal.
OE
= "
l"
; high irnpedance
OT2
0
OE
= "
H " ; output as the 4-bit code .
(
28
-
-
Hide quick links:
Advertisement
Table of Contents
