MT8870D/MT8870D-1
Data Sheet
The value of t
DP
is a device parameter (see Figure 11) and t
REC
is the minimum signal duration to be recognized by
the receiver. A value for C of 0.1
µF
is recommended for most applications, leaving R to be selected by the
designer.
t
GTP
=(R
P
C
1
)In[V
DD
/(V
DD
-V
TSt
)]
V
DD
C
1
St/GT
R
1
ESt
R
2
a) decreasing t
GTP
; (t
GTP
<t
GTA
)
t
GTA
=(R
1
C
1
)In(V
DD
/V
TSt
)
R
P
=(R
1
R
2
)/(R
1
+R
2
)
t
GTP
=(R
1
C
1
)In[V
DD
/(V
DD
-V
TSt
)]
V
DD
C
1
St/GT
R
2
b) decreasing t
GTA
; (t
GTP
>t
GTA
)
t
GTA
=(R
P
C
1
)In(V
DD
/V
TSt
)
R
P
=(R
1
R
2
)/(R
1
+R
2
)
R
1
ESt
Figure 5 - Guard Time Adjustment
Digit
ANY
1
2
3
4
5
6
7
8
9
0
*
#
A
B
C
D
A
B
C
D
TOE
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
INH
X
X
X
X
X
X
X
X
X
X
X
X
X
L
L
L
L
H
H
H
H
ESt
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
L
L
L
undetected, the output code
will remain the same as the
previous detected code
Q
4
Z
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
Q
3
Z
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
Q
2
Z
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
Q
1
Z
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
Table 1 - Functional Decode Table
L=LOGIC LOW, H=LOGIC HIGH, Z=HIGH IMPEDANCE
X = DON‘T CARE
5
Zarlink Semiconductor Inc.
ZARLINK [ ZARLINK SEMICONDUCTOR INC ]
