5

LT1237

CC

HARA TERISTICS

A

TYPICALPERFOR

CE

Receiver Short-Circuit Current

Driver Short-Circuit Current

TEMPERATURE (

°C)

–55

20

25

30

25

75

1237 G10

15

10

–25

0

50

100

125

5

0

+

–

TEMPERATURE (

°C)

–55

0

20

50

0

50

75

1237 G11

10

40

30

–25

25

100

125

RX1 TO RX4

+

RX1 TO RX4

–

–

+

Receiver Output Waveforms

DRIVER OUTPUT

DRIVER OUTPUT

RX5 OUTPUT

1237 G12

RX1 TO RX4

OUTPUT

INPUT

1237 G13

INPUT

Driver Output Waveforms

PI FU CTIO S

with a 0.1

µF ceramic capacitor close to the package pin.

Insufficient supply bypassing can result in low output

drive levels and erratic charge pump operation.

GND: Ground Pin.

ON/OFF: TTL/CMOS Compatible Operating Mode Control.

A logic low puts the device in the low power shutdown

mode. All three drivers and four receivers (RX1, RX2, RX3,

and RX4) assume a high impedance output state in shut-

down. Only receiver RX5 remains active while the trans-

ceiver is in shutdown. The transceiver consumes only

60

µA of supply current while in shutdown. 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 driver

outputs 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

transceiver. 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.

1.5V. This pin requires an external charge storage capaci-

tor C

tors may be used to reduce supply ripple. The ratio of the

≈

storage capacitor C

≥ 0.1µF. See the Applications Infor-

mation section for guidance in choosing filter capacitors