Isolated RS485 Interface Reference Design
California Eastern Laboratories announces the release of a 2.5 Mb/s isolated RS485 communications interface reference design. The design includes NEC’s digital high speed PS9821 optocouplers and National Semiconductor’s low power LMS1487 differential bus transceiver. Designed to operate over an input power range of 3.3 to 5 V, the interface can provide up to 500 mW of supplementary output power. The additional power can be implemented to drive external loads such as other transceiver nodes, A/D converters, point of sales (POS) card readers and RFID scanners. Designers working with RS485 interfaces will benefit from the flexibility this discrete design provides. NEC’s PS9821 family of optocouplers provides high isolation with data rates up to 15 Mb/s over the full 3.3 to 5 V input power range. They are available in single or dual-channel SO8 packages. National Semiconductor’s LMS1487 transceiver operates at up to 2.5 Mb/s, with full ANSI, RS485A and RS422-B compliance in an 8-pin SOIC package.
California Eastern Laboratories