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STC3485E
3.3V-Powered, ±15kV ESD-Protected,
and Slew-Rate-Limited True RS-485 Transceivers
General Description
The STC3485E is +15 KV ESD protected, slew-rate limited, ultra lower differential line transceivers which provide full RS485 compat-
ibility while operating from single 3.3V supply. Each part contains one driver and one receiver, which is designed for data transmission
with extended common mode range (-7V to 12V). The STC3485E features slew-rate limited driver that minimizes EMI and reduces
reflections caused by improperly terminated cables, allowing error-free data transmission at data rate up to 500kbps.
All devices feature enhanced electrostatic discharge (ESD) protection. All transmitter outputs and receiver inputs are protected to
±15kV using IEC 1000-4-2 Air-Gap Discharge and ±15kV using the Human Body Model.
Drivers are 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
both inputs are open, shorted or idle.
Both parts have power up/down glitch free driver outputs permit live insertion or removal of transceiver from/to data bus. The
CMOS design offers significant power savings without sacrificing ruggedness against overload or ESD damage. Typical quiescent
current is only 500 µA while operating and 1 µA in shutdown.
The STC3485E are fully specified over the commercial an extended industrial temperature range and are available in 8-pin and DIP
packages.
Applications
Telecommunications
Low-Power RS-485 Transceivers
Integrated Services Digital Networks
Transceivers for EMI-Sensitive Applications
Packet Switching
Features
ESD Protection for RS-485 I/O Pins
±15kV— Human Body Model
±15kV— IEC 1000-4-2, Air-Gap Discharge
Operate from a Single 3.3V supply
Interoperable with +5V Logic
Slew-Rate Limited for Errorless Data Transmission
1 µA 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
Ordering Information
PART
TEMP. RANGE
PIN-PACKAGE
STC3485EESA
-40°C to +85°C
8 SO
STC3485EEPA
-40°C to +85°C
8 Plastic DIP
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