UM3352EESA

The UM3352E series are ±15kV ESD-protected, high-speed, half-duplex transceivers for RS-485 communication that contain one driver and one receiver. The device features fail-safe circuitry, which guarantees a logic-high receiver output when the receiver inputs are open, shorted or idle. This means that the receiver output will be logic high if all transmitters on a terminated bus are disabled (high impedance). The UM3352E features reduced slew-rate driver that minimizes EMI and reduces reflections caused by improperly terminated cables, allowing error-free data transmission up to 500kbps. It also features enhanced ESD protection. All transmitter outputs and receiver inputs incorporate advanced structures allowing them to survive ESD events in excess of ±15kV Human Body Mode and IEC61000-4-2 Air Discharge Mode, ±8kV IEC61000-4-2 Contact Discharge Mode. New ESD structures protect the device whether or not it is powered up and without degrading the RS-485 common mode range of -7V to 12V. The UM3352E includes a hot swap circuit inside, which allows live cable insertion and removal. Proprietary protection circuit built on A and B ports, can dissipate high surge current up to 6A to ground. The transceivers typically draw 450μA of supply current when unloaded, or when fully loaded with the drivers disabled. The device has a 1/8-unit-load receiver input impedance that allows up to 256 transceivers on the bus and are intended for half-duplex communications.

Applications

• RS-485 Transceivers
• Intelligent Meters and Sensors
• Industrial Control
• Lighting Systems
• Security Systems
• HVAC Application

Key features

• ESD Protection for RS-485 I/O Pins ±15kV —Human Body Mode
• ±15kV —IEC61000-4-2, Air Discharge Mode
• ±8kV —IEC61000-4-2, Contact Discharge Mode
• True Fail-Safe Receiver
• Enhanced Slew-Rate Limiting Facilitates Error-Free Data Transmission
• 2μA Low-Current Shutdown Mode
• -7V to +12V Common-Mode Input Voltage Range
• Allows up to 256 Transceivers on the Bus
• Thermal Shutdown
• Current-Limiting for Driver Overload Protection
• Hot Swap Capability