LT1342 Linear Technology, LT1342 Datasheet - Page 5

• Manufacturer Part Number: LT1342
• Description: 5V RS232 Transceiver with 3V Logic Interface
• Manufacturer: Linear Technology

TYPICAL PERFOR
PI FU CTIO S
V
with a 0.1 F ceramic capacitor close to the package pin.
Insufficient supply bypassing can result in low output
drive levels and erratic charge pump operation.
V
outputs. Decouple with a 0.1 F ceramic capacitor.
GND: Ground Pin.
ON/OFF: A TTL/CMOS Compatible Operating Mode Con-
trol. A logic low puts the device in the low power shutdown
mode. Drivers and receivers assume a high impedance
state in shutdown. The transceiver consumes almost no
supply current while in shutdown. A logic high fully
enables the transceiver. An ON/OFF logic low signal super-
sedes the state of the DRIVER DISABLE pin.
CC
L
: 3V Logic Supply Pin. Provides power to the receiver
U
: 5V Input Supply Pin. This pin should be decoupled
RX5 OUTPUT
RX1 TO RX4
C
C
U
OUTPUT
L
L
= 50pF
= 50pF
INPUT
30
25
10
20
15
5
0
–55
Receiver Output Waveforms
Driver Short-Circuit Current
V
L
= 3V
–25
U
0
TEMPERATURE ( C)
W
25
A
50
U
CE
75
I
I
SC
SC
LT1342 • TPC10
C
+
–
100
HARA TERISTICS
LT1342 • TPC12
125
C
DRIVER OUTPUT
DRIVER OUTPUT
DRIVER DISABLE: This pin provides an alternate control
for the charge pump and RS232 drivers. A logic high on
this pin shuts down the charge pump and places all drivers
in a high impedance state. All five receivers remain active
under these conditions. Floating the DRIVER DISABLE pin
or driving it to a logic low level fully enables the trans-
ceiver. A logic low on the ON/OFF pin supersedes the state
of the DRIVER DISABLE pin. Supply current drops to 3mA
when in driver disable mode.
V
1.5V. This pin requires an external charge storage capaci-
tor C
transceivers, the V
common charge storage capacitors. Larger value capaci-
tors may be used to reduce supply ripple.
+
C
: Positive Supply Output (RS232 Drivers). V
L
= 2500pF
R
R
L
INPUT
L
= 3k
= 3k
30
50
40
20
10
0
0.1 F, tied to ground or V
–55
Driver Output Waveforms
Receiver Short-Circuit Current
–25
RX1 TO RX4
RX5 I
RX5 I
I
0
SC
+
TEMPERATURE ( C)
+
SC
SC
and V
–
+
25
RX1 TO RX4
I
SC
50
–
–
pins may be paralleled into
75
LT1342 • TPC11
100
LT1342 • TPC13
CC
125
. With multiple
LT1342
+
2V
CC
5
–