STMicroelectronics ST4E1250F Full-Duplex RS485 Transceivers
STMicroelectronics ST4E1250F Full-Duplex RS485 Transceivers are low-power differential line transceivers for full-duplex RS485 data transmission. The transceivers operate at up to 50Mbps, ideal for multi-point applications in constrained, harsh industrial environments. The devices offer strong protection against ESD transients, with bus pins capable of withstanding ±12kV IEC 61000-4-2 contact discharge. Robust hot-swap functionality enables reliable operation during power-up, power-down, and live plug-in events. A fail-safe receiver delivers a logic-high output when inputs are open, shorted, or connected to a terminated bus. High receiver hysteresis enhances noise immunity and helps maintain signal integrity. The STMicroelectronics ST4E1250F is available in a small 3mm x 3mm DFN10 or standard SO14 package and operates over a -40°C to +125°C temperature range.
Features
- Meets or exceeds the requirements of the TIA/EIA-485A standard
- 3V to 5.5V supply voltage range
- Differential output exceeds 2.1V for PROFIBUS compatibility with a 5V supply
- High speed - up to 50Mbps data rate
- Up to 128 bus nodes
- 70mV receiver hysteresis
- Full-duplex topology
- Low quiescent current in shutdown mode
- -40°C to +125°C operating temperature range
- Integrated protections
- Fail-safe receiver (bus open, idle, and shorted)
- Thermal shutdown protection
- Hot swap capability
- Bus I/O ESD protection
- ±12kV IEC61000-4-2 contact discharge
- ±30kV Human Body Model (HBM)
- ±4kV IEC61000-4-4 fast transient burst
- Available in a small 3mm x 3mm DFN10 or a standard SO14 package
Applications
- Motion controllers
- Optical networks
- Building automation and safety
- Video surveillance (building, traffic monitoring)
- Backplane bus
- Grid infrastructure
- Robotics
Specifications
- 3V to 5.5V device operating supply voltage range
- -7V to 12V input level range at any bus terminal (separated or common-mode)
- ±70mA operating output current (driver Y, Z)
- 60Ω typical differential load resistance, 54Ω minimum
- 50pF typical differential load capacitance
- 50Mbps maximum signaling rate
- 394mW to 397mW power dissipation range with driver and receiver enabled
- Typical thermal resistance
- 55°C/W junction-to-ambient, EP connected to ground and use of thermal vias
- 105°C/W junction-to-ambient on a single-layer PCB
Block Diagram
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