±80V Fault-Protected, Fail-Safe,

1/4-Unit Load, +3.3V RS-485 Transceiver

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11

Applications Information

128 Transceivers on the Bus

The standard RS-485 receiver input impedance is 12k

Ω

(one-unit load), and a standard driver can drive up to

32-unit loads. The MAX3430 transceiver 1/4-unit-load

receiver input impedance (48k

Ω) allows up to 128

transceivers connected in parallel on one communica-

tion line. Connect any combination of these devices,

and/or other RS-485 devices, for a maximum of 32 unit

loads to the line.

RS-485 Applications

The MAX3430 transceiver provides bidirectional data

communications on multipoint bus transmission lines.

The RS-485 standard covers line lengths up to 4000ft.

The signal line must be terminated at both ends in its

characteristic impedance, and stub lengths off the

main line kept as short as possible.

Chip Information

TRANSISTOR COUNT: 300

PROCESS: BiCMOS