11

LTC1387

S

APPLICATI

I FOR ATIO

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-

tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

Figure 14. Full-Duplex RS232 (1-Channel), Half-Duplex RS485

A

B

Y

Z

ON

RXEN

DXEN

485/232

CONTROLLER

DX

RXEN

DXEN

MODE

INTERFACE

A

B

Y

Z

RS232

RS485

RS232

RS485

RS485

RS485

RS232

RS485

SHUTDOWN

MODE

MODE

MODE

RXEN = 1

RXEN = 1

RXEN = 0

DXEN = 1

DXEN = 1

DXEN = 0

MODE = 0

MODE = 1

MODE = X

1387 • F15

LTC1387

RX

RXD

TXD

Figure 15. Full-Duplex RS232 (1-Channel), Full-Duplex RS485/RS422

Figure 16. Full-Duplex RS232 (2-Channel), Full-Duplex RS485/RS422 with SLEW Control

A

B

Y

Z

ON

RXEN

DXEN

485/232

CONTROLLER

DX1

DX2/SLEW

ON

RXEN

DXEN

MODE

INTERFACE

A

B

Y

Z

RS232

RS485

RS232

RS485

RS485

RS485

RS232

RS485

SHUTDOWN

MODE

MODE

MODE

ON = 1

ON = 1

ON = 0

RXEN = 1

RXEN = 1

RXEN = 0

DXEN = 1

DXEN = 1

DXEN = 0

MODE = 0

MODE = 1

MODE = X

1387 • F16

LTC1387

RX1

RX2

RXD

RS232

CTS

TXD

RS232

RTS

A

B

Y

Z

ON

RXEN

DXEN

485/232

CONTROLLER

DX

RXEN

DXEN

MODE

INTERFACE

A

B

RS232

RS232

RS485

RS485

RS232

RS485

RS485

SHUTDOWN

MODE

TRANSMIT MODE

RECEIVE MODE

MODE

RXEN = 1

RXEN = 0

RXEN = 1

RXEN = 0

DXEN = 0

DXEN = 1

DXEN = 0

DXEN = 0

MODE = 0

MODE = 1

MODE = 1

MODE = 0

1387 • F14

LTC1387

RX

TXD

RXD