Independent driver/receiver enable/disable Power supply voltage selection: left position 3V3, right position 5V This table shows how the pinout on RS485 Isolator 2 Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns). Heating, ventilation, and air-conditioning (HVAC) networks, Industrial field buses, Building automation, Utility networksĪDM2867E Power Isolated RS-485 Transceiver from Analog Devicesĥ.7 kV rms isolated full duplex RS-485/RS-422 transceiver, Cable invert smart feature, High speed 25 Mbps data rate, Supports 196 bus nodes, Full hot swap support The onboard SMD jumper labeled as VCC SEL allows voltage selection for interfacing with both 3.3V and 5V MCUs. The RS485 Isolator 2 Click board™ can be supplied and interfaced with both 3.3V and 5V without the need for any external components. During this start-up time, it is not recommended to assert the DE driver enable signal. The integrated isoPower isolated dc-to-dc converter requires up to 10 ms to power up to its set point of 3.3 V or 5 V. Any combination of these devices and other RS-485 transceivers with a total of 32 unit loads or fewer can be connected to the line. The ADM2867E transceiver has a 1/6 unit load receiver input impedance (72 kΩ), allowing up to 196 transceivers to be connected in parallel on one communication line. The standard RS-485 receiver input impedance is 12 kΩ (1 unit load), and the standard driver can drive up to 32 unit loads. When the receiver is inverted, the device maintains a Logic 1 receiver output with a 30 mV noise margin when inputs are shorted together or open circuit. Use the INR pin to correct receiver functionality when A and B are wired incorrectly. Use the IND pin to correct driver functionality when Y and Z are wired incorrectly. The RS485 Isolator 2 features separate digital logic pins, IND and INR, to correct cases where the driver and/or receiver are wired incorrectly. In these applications, the increased differential voltage extends the reach of the device to longer cable lengths. This architecture is particularly useful when operating the device at lower data rates over long cable runs, where the dc resistance of the transmission line dominates signal attenuation. The ADM2867E features a proprietary transmitter architecture with a low driver output impedance, resulting in an increased differential output voltage. The integrated dc-to-dc converter is optimized to minimize radiated electromagnetic interference (EMI), and allows designers to meet the CISPR22/EN55022 Class B requirements on a 2-layer PCB. Because no direct electrical connection exists between the top and bottom coil, the primary and secondary side of the device remain galvanically isolated. By exciting the upper coil with an ac signal, power is magnetically coupled across the isolation barrier where it is rectified and regulated. The isolated dc-to-dc converter is constructed of a set of chip scale coplanar coils that are separated by an insulating material. The RS485 Isolator 2 Click is based on ADM2867E from Analog Devices. It includes a flexible integrated dc-to-dc converter optimized for low radiated emissions (EMI).
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