HT3085EBRDZ

The ISL8308XE series are single transceivers fabricated in BiCMOS process with ESD protection, operating from a 5V supply, and compliant with RS-485 and RS-422 balanced communication standards. Each driver output and receiver input can withstand ±15kV ESD strikes without latch-up, and unlike competing devices, this series is specified for 10%-tolerance supplies (4.5V to 5.5V). These devices feature extremely low bus current (+125μA to -75μA), presenting a true "1/8 unit load" on the RS-485 bus. This allows up to 256 transceivers to be connected on a single network without violating the 32 unit load maximum specified by RS-485, eliminating the need for repeaters. In remote utility metering systems, for example, individual meter readings are routed via RS-485 networks to a concentrator, so the high allowable node count minimizes the number of repeaters required. All meter data is then read from the concentrator through a single access port or wireless link. The receiver inputs feature a "fully fail-safe" design that guarantees a logic-high output when the receiver inputs are floating, shorted, or terminated but undriven. The HT3080E, HT3082E, HT3083E, and HT3085E incorporate slew-rate-limited drivers to reduce EMI and minimize signal reflections from improperly terminated transmission lines or unterminated stubs in multipoint and multidrop applications. The slew-rate-limited versions also include receiver input filtering to enhance noise immunity in the presence of slow input signals. Hot-swap circuitry ensures that the driver and receiver outputs remain high-impedance until the supply is stable, and the driver outputs are fully short-circuit protected.

Applications

• Automatic utility metering systems
• High node count systems
• Factory automation
• Fieldbus networks
• Security camera networks

Key features

• Lead-free with annealing process version available (RoHS compliant)
• RS-485 I/O pin ESD protection: ±15kV Human Body Model Level 3 ESD protection on all pins
• Fully fail-safe receiver (open, short, terminated, and floating)
• Hot-plug circuitry (HT3080E, HT3082E, HT3083E, HT3085E)
• Transmit and receive outputs remain three-state during power-up/power-down
• True 1/8 unit load, allowing up to 256 devices on the bus
• Specified for single 5V, 10% tolerance supply
• High data rate up to 10Mbps
• Low quiescent supply current of 530μA
• Ultra-low shutdown supply current of 70nA
• Wide common-mode input voltage range of -7V to +12V
• Half-duplex and full-duplex pinouts
• Three-state receiver and transmitter outputs
• Current limiting and thermal shutdown for driver overload protection