5.7kV Signal and Power Isolated Half-Duplex RS-485 Transceiver with Fault Protection

The ADM2895E/ADM2895E-1 are 5.7kVRMS signal and power isolated RS-485 transceivers with ±60V fault protection on the RS-485 A and B pins. These devices are designed for balanced transmission lines and comply with ANSI/TIA/EIA-485-A-98 and ISO 8482:1987(E). The devices can pass radiated emissions testing to the EN 55032 Class B standard with margin on a 2-layer printed circuit board (PCB) with high-frequency decoupling capacitors and two small external 0402 ferrites on isolated power and ground pins. The device features an integrated, low electromagnetic interference (EMI), isolated DC-to-DC converter, which eliminates the need for an external isolated power supply. The isolation barrier provides immunity to system level electromagnetic compatibility (EMC) standards. The devices are suitable for applications that require reinforced insulation against working voltages of 400VRMS and 566VDC for the lifetime of the device. The devices are protected against ±4kV contact IEC 61000-4-2 and ±15kV human body model (HBM) electrostatic discharge (ESD) events on the RS-485 A and B pins and ±8kV contact IEC 61000-4-2 ESD across the barrier without latch-up or damage.

The ADM2895E/ADM2895E-1 feature overvoltage protection on the RS-485 A and B pins to withstand up to ±60V DC or AC peak to the transceiver side GND2. This allows for robust protection against transients and accidental connection to ±12V or ±24V power supplies. The common-mode range of the device is extended to ±25V for applications with large ground offsets and long cable runs.

Please see the data sheet for the full description.

APPLICATIONS

* Heating, ventilation, and air conditioning (HVAC) networks

* Industrial field buses

* Building automation

* Utility networks

* Energy meters

* 5.7kVRMS isolated half-duplex RS-485/RS-422 transceiver

* ±60V fault protection on RS-485 A and B pins

* Low radiated emissions, integrated, isolated DC-to-DC converter

* Meets EN 55032 Class B radiated emissions on a 2-layer PCB

* Robust protection on the RS-485 A and B bus pins

* ≥ ±4kV IEC 61000-4-2 ESD

* ±10kV HBM ESD

* ≥ ±4kV IEC 61000-4-4 EFT

* Extended ±25V common-mode range

* Two speed options

* ADM2895E - low speed 250kbps for EMI control

* ADM2895E-1 - high speed 20Mbps data rate

* Flexible power supplies

* Primary input VCC supply of 3.0V to 5.5V

* Primary logic VIO supply of 1.7V to 5.5V

* VSEL pin to select isolated VISO supply of 5V (VCC > 4.5V) or 3.3V