The ISL3247xE are fault-protected, extended common-mode range differential transceivers that exceed the RS-485 and RS-422 standards for balanced communication. The RS-485 bus pins (driver outputs and receiver inputs) are fault protected against overvoltages up to ±60V and are protected against ±16.5kV ESD strikes without latch-up. Additionally, these transceivers operate in environments with common-mode voltages up to ±15V (exceeds the RS-485 requirement), making this fault-protected RS-485 family one of the most robust on the market.
The transmitters (Tx) deliver an exceptional 2.5V (typical) differential output voltage into the RS-485 specified 54Ω load. This yields better noise immunity than standard RS-485 ICs or allows up to six 120Ω terminations in star topologies.The receiver (Rx) inputs feature a full fail-safe design that ensures a logic high Rx output if the Rx inputs are floating, shorted, or on a terminated but undriven (idle) bus. The Rx outputs feature high drive levels; typically, 15mA at VOL = 1V (to ease the design of opto-coupled isolated interfaces).
Half duplex (Rx inputs and Tx outputs multiplexed together) and full duplex pinouts are available.
For a fault-protected RS-485 transceiver with a ±25V extended common-mode range, see the ISL32490E and ISL32483E datasheets.
Feature
- Fault protected RS-485 bus pins: Up to ±60V
- Extended common-mode range: ±15V
- larger than required for RS-485
- 1/4 unit load for up to 128 devices on the bus
- ±16.5kV HBM ESD protection on RS-485 bus pins
- High transient over-voltage tolerance: ±80V
- Full fail-safe (open, short, terminated) RS-485 receivers
- High Rx IOL for opto-couplers in isolated designs
- Hot plug circuitry: Tx and Rx outputs remain three-state during power-up/power-down
- RS-485 data rates: 250kbps to 15Mbps
- Low quiescent supply current: 2.3mA
- Ultra low shutdown supply current: 10µA
