Simplified Block Diagram
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- 10-Pin µMAX Package: Smallest 10-Pin Package
- Software-Selectable Half-/Full-Duplex Operation (MAX1485/MAX1486)
- 0.1µA Low-Current Shutdown Mode (MAX1481)
- Slew-Rate Limiting Allows Error-Free Data Transmission (MAX1481/MAX1485)
- 12Mbps High-Speed Operation (MAX1484/MAX1486)
- Allow up to 256 Transceivers on the Bus
- Battery-Powered Applications
- Handheld Equipment
- Industrial Control Local Area Networks
- Level Translators
- Low-Power RS-422/RS-485 Communications
- Transceivers for EMI-Sensitive Applications
The software-selectable, half-/full-duplex MAX1485/MAX1486 make obsolete the normally larger and more expensive solutions required for selectable half-/full-duplex RS-485/RS-422 operation: 1) a 14-pin, full-duplex transceiver configured via jumpers between receiver and transmitter lines, or 2) two 8-pin, half-duplex transceivers, which require an additional inverter logic gate for software selectability.
The MAX1481/MAX1484 are functionally equivalent to the industry-standard MAX491 and 75180, and are designed for space-constrained, full-duplex RS-422 applications.
All parts contain one driver and one receiver and feature a 1/8-unit-load receiver input impedance, allowing up to 256 transceivers on the bus. The MAX1481/MAX1485 feature reduced-slew-rate drivers that minimize EMI and reduce reflections caused by improperly terminated cables, allowing error-free data transmission up to 250kbps. The MAX1484/MAX1486 driver slew rates are not limited, allowing them to transmit up to 12Mbps.
The MAX1481/MAX1484/MAX1485/MAX1486 draw only 300µA of supply current. The MAX1481 has a low-power shutdown mode that reduces supply current to only 0.1µA. All devices operate from a single 5V supply.
Drivers are output short-circuit current limited and are protected against excessive power dissipation by thermal-shutdown circuitry that places the driver outputs into a high-impedance state. The receiver input has a fail-safe feature that guarantees a logic-high output if the input is open circuit.