LT1130A/LT1140A Series
TYPICAL PERFOR A CE CHARACTERISTICS
Driver Short-Circuit Current
30
50
SHORT-CIRCUIT CURRENT (mA)
25
ISC
+
20
15
ISC
–
10
5
0
–55 –25
SHORT-CIRCUIT CURRENT (mA)
50
25
75
0
TEMPERATURE (°C)
Shutdown to Driver Output
DRIVER
OUTPUT HIGH
R
L
= 3k
10
5
0
DRIVER – 5
OUTPUT LOW
R
L
= 3k – 10
ON/OFF PIN
DRIVER OUTPUT
R
L
= 3k
C
L
= 2500pF
DRIVER OUTPUT
R
L
= 3k
PI FU CTIO S
V
CC
:
5V Input Supply Pin. Supply current drops to zero in
the shutdown mode. This pin should be decoupled with a
0.1µF ceramic capacitor close to the package pin. Insuffi-
cient supply bypassing can result in low output drive levels
and erratic charge pump operation.
GND:
Ground Pin.
ON/OFF:
Control the operation mode of the device and is
TTL/CMOS compatible. A logic low puts the device in the
shutdown mode which reduces input supply curent to zero
and places all of the drivers and receivers in high imped-
ance state. A logic high fully enables the transceiver.
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. Receivers remain active under
these conditions. Floating the DRIVER DISABLE pin or
driving it to a logic low level fully enables the transceiver.
A logic low on the ON/OFF pin supersedes the state of the
DRIVER DISABLE pin. Supply current drops to 4mA when
in driver disable mode.
V
+
:
Positive Supply Output (RS232 Drivers). V
+
≈
2V
CC
–
1.5V. This pin requires an external charge storage capaci-
tor C
≥
1.0µF, tied to ground or V
CC
. Larger value capaci-
tors may be used to reduce supply ripple. With multiple
transceivers, the V
+
and V
–
pins may be paralleled into
common capacitors. For large numbers of transceivers,
increasing the size of the shared common storage capaci-
tors is recommended to reduce ripple.
U W
Receiver Short-Circuit Current
40
ISC
–
30
ISC
+
20
10
100
125
0
–55 –25
50
25
0
75
TEMPERATURE (°C)
100
125
LT1137A • TPC10
LT1137A • TPC11
Driver Output Waveforms
INPUT
LT1137A • TPC12
LT1137A • TPC13
U
U
U
7
LINER [ LINEAR TECHNOLOGY ]
