MC145407 Motorola, MC145407 Datasheet - Page 6

• Manufacturer Part Number: MC145407
• Description: 5 Volt Only Driver / Recevier
• Manufacturer: Motorola

ESD CONSIDERATIONS
sible to the outside world is essential. High static voltages
applied to the pins when someone touches them either di-
rectly or indirectly can cause damage to gate oxides and
transistor junctions by coupling a portion of the energy from
the I/O pin to the power supply busses of the IC. This cou-
pling will usually occur through the internal ESD protection
diodes. The key to protecting the IC is to shunt as much of
the energy to ground as possible before it enters the IC. Fig-
ure 7 shows a technique which will clamp the ESD voltage at
approximately + 15 V using the MMBZ15VDLT1. Any resid-
ual voltage which appears on the supply pins is shunted to
ground through the 0.1 F capacitors.
OPERATION WITH SMALLER VALUE CHARGE PUMP
CAPS
MC145407
6
RING
TIP
ESD protection on IC devices that have their pins acces-
The MC145407 is characterized in the electrical tables
INPUT
DTMF
V SS
V DD
10 k
* Line protection circuit
BYPASS
BYPASS
0.1 F
0.1 F
APPLICATIONS INFORMATION
20 k
R DSI
*
V DD
10 F
600:600
C DSI RTLA
0.1 F
0.1 F
C CDT
+
0.1 F
R Tx
600
C FB
20
16
18
10
19
17
15
4
1
Figure 4. 5 V, 300 Baud Modem with EIA–232–E Interface
TLA
DSI
RxA1
ExI
FB
V AG
CDT
TxA
RxA2
MC145442
MC145443
12
V DD
V SS
OR
6
MODE
X out
SQT
CDA
TxD
RxD
0.1 F
X in
CD
LB
14
11
13
9
8
3
5
2
7
10 k
10 k
10 k
C CDA
0.1 F
3.579
MHz
+ 5 V
using 10 F charge pump caps to illustrate its capability in
driving a companion MC145406 or MC145403. If there is no
requirement to support a second interface device and/or the
charge pump is not being used to power any other com-
ponents, the MC145407 is capable of complying with
EIA–232–E and V.28 with smaller value charge pump caps.
Table 1 summarizes driver performance with both 2.2 F and
1.0 F charge pump caps.
Tx V OH @ 25 C
Tx V OH @ 85 C
Tx V OL @ 25 C
Tx V OL @ 85 C
Tx Slew Rate @ 25 C
Tx Slew Rate @ 85 C
1.0 F
0.1 F
15
Parameter
16
13
3
1
1.0 F
1.0 F
Table 1. Typical Performance
C2 – V DD
C2 +
DI1
DO1
DI2
DI3
17
V SS
MC145407
+
4
V CC C1 –
GND
19
2
C1 +
Rx1
Rx2
Rx3
Tx1
Tx2
0.1 F
6
8
7
9
5
8.0 V/ s
7.0 V/ s
2.2 F
– 6.5
– 6.1
7.3
7.2
1.0 F
8
2
3
7
MOTOROLA
CONNECTOR
8.0 V/ s
7.0 V/ s
EIA–232–E
1.0 F
– 6.4
– 6.0
DB–25
7.2
7.1