LT1280A Linear Technology, LT1280A Datasheet - Page 6

• Manufacturer Part Number: LT1280A
• Description: Low Power 5V RS232 Dual Driver/Receiver with 0.1uF Capacitors
• Manufacturer: Linear Technology

LT1280A/LT1281A
The RS232 line inputs of the LT1280A/LT1281A have on-
chip protection from ESD transients up to 10kV. The
protection structures act to divert the static discharge
safely to system ground. In order for the ESD protection to
function effectively, the power supply and ground pins of
the circuit must be connected to ground through low
impedances. The power supply decoupling capacitors and
charge pump storage capacitors provide this low imped-
ance in normal application of the circuit. The only con-
straint is that low ESR capacitors must be used for
bypassing and charge storage. ESD testing must be done
with pins V
connected with low ESR capacitors.
6
ESD PROTECTIO
TYPICAL
CC
, V
A
SHUTDOWN
L
PPLICATI
, V
TTL OUTPUT
TTL OUTPUT
+
TTL INPUT
TTL INPUT
, V
1 F
1 F
–
+
+
, and GND shorted to ground or
U
18
11
12
13
10
2
4
5
6
O
ON/OFF
C1
C2
C2
C1
–
U
+
+
–
LT1280A
GND
Supporting an LT1039 (Triple Driver/Receiver)
16
5k
5k
V
V
V
CC
+
–
17
8
15
14
9
3
7
RS232 OUTPUT
RS232 OUTPUT
RS232 INPUT
RS232 INPUT
+
1 F
5V
0.1 F
0.1 F
+
TTL OUTPUT
TTL OUTPUT
TTL OUTPUT
TTL INPUT
TTL INPUT
TTL INPUT
+
+
1 F
PROTECTED
LINE PINS
TO 10kV
0.1 F
RS232
0.1 F
+
18
15
13
16
14
12
11
1
9
+
V
V
V
CC
+
–
5
6
7
8
9
1
2
3
4
NC
C1
V
C1
C2
C2
DR2 OUT
RX2 IN
V
LT1039
+
–
GND
ESD Test Circuit
+
–
+
–
10
ON/OFF
LT1280A
30k
30k
30k
4
6
8
3
5
7
17
DR1 OUT
RX1 OUT
RX2 OUT
ON/OFF
5V V
RX1 IN
DR1 IN
DR2 IN
RS232 OUTPUT
RS232 OUTPUT
RS232 OUTPUT
RS232 INPUT
RS232 INPUT
RS232 INPUT
GND
LT1280A • TA04
CC
18
17
16
15
14
13
12
11
10
RS232
LINE PINS
PROTECTED
TO 10kV
1280A ESD TC
+
0.1 F