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Overview

Description

These Renesas RS-485/RS-422 devices are BiCMOS 3. 3V powered, single transceivers that meet both the RS-485 and RS-422 standards for balanced communication. Unlike competitive devices, this Renesas family is specified for 10% tolerance supplies (3V to 3. 6V). The ISL83483 and ISL83488 use slew rate limited drivers which reduce EMI, and minimize reflections from improperly terminated transmission lines, or unterminated stubs in multidrop and multipoint applications. Data rates up to 10Mbps are achievable by using the ISL83485, ISL83490, or ISL83491, which feature higher slew rates. Logic inputs (for example, DI and DE) accept signals in excess of 5. 5V, making them compatible with 5V logic families. Receiver (Rx) inputs feature a “fail-safe if open” design, which ensures a logic high output if Rx inputs are floating. All devices present a “single unit load” to the RS-485 bus, which allows up to 32 transceivers on the network. Driver (Tx) outputs are short-circuit protected, even for voltages exceeding the power supply voltage. Additionally, on-chip thermal shutdown circuitry disables the Tx outputs to prevent damage if power dissipation becomes excessive. The ISL83488, ISL83490, and ISL83491 are configured for full duplex (separate Rx input and Tx output pins) applications. The ISL83488 and ISL83490 are offered in space saving 8 Ld packages for applications not requiring Rx and Tx output disable functions (for example, point-to-point and RS-422). Half duplex configurations (ISL83483, ISL83485) multiplex the Rx inputs and Tx outputs to provide transceivers with Rx and Tx disable functions in 8 Ld packages.

Features

  • Operate from a Single +3.3V Supply (10% Tolerance)
  • Interoperable with 5V Logic
  • High Data Rates: up to 10Mbps
  • Single Unit Load Allows up to 32 Devices on the Bus
  • Slew Rate Limited Versions for Error Free Data Transmission (ISL83483, ISL83488): up to 250kbps
  • Low Current Shutdown Mode (ISL83483, ISL83485, ISL83491): 15nA
  • -7V to +12V Common Mode Input Voltage Range
  • Three State Rx and Tx Outputs (Except ISL83488, ISL83490)
  • 10ns Propagation Delay, 1ns Skew (ISL83485, ISL83490, ISL83491)
  • Full Duplex and Half Duplex Pinouts
  • Current Limiting and Thermal Shutdown for driver Overload Protection
  • Pb-free available

Comparison

Applications

Documentation

Design & Development

Models

ECAD Models

Schematic symbols, PCB footprints, and 3D CAD models from SamacSys can be found by clicking on the CAD Model links in the Product Options table. If a symbol or model isn't available, it can be requested directly from SamacSys.

Diagram of ECAD Models

Models

Type Title Date
Model - IBIS IBS 39 KB
1 item

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Support Communities

  1. Related to RS 485

    I used ISL83485 IC for RS 485. I used UART communication framework.I used ssp 1.6.0 I am able to write data but not able to read. ssp_err_t err=sf_comms0_read(rx_uart_data7, RX_WORD_LENGTH, TX_WAIT_FOREVER); But read not wait and ...

    Sep 8, 2020
  2. Related to RS 485

    I used ISL83485 IC for RS 485. I used UART communication framework.I used ssp 1.6.0 I am able to write data but not able to read. ssp_err_t err=sf_comms0_read(rx_uart_data7, RX_WORD_LENGTH, TX_WAIT_FOREVER); But read not wait and ...

    Sep 8, 2020
  3. ISL83491 Half Duplex Support

    I'm aware that the ISL83491 is intended for use as a full duplex transceiver. Can the hardware of the driver still support connection to a half-duplex transceiver, for example by shorting the driver and receiver cables?

    Apr 5, 2025

FAQs

  1. Do we need fail-safe pull-up resistors and can we have different voltage transceivers on the same RS-485 bus?

    ... on the same bus. For the fail-safes, you only need a pull-up on the input receiver. If your circuit is unidirectional (i.e., ISL83485 transmits to ISL8485) you need only have the fail-safe on the ISL8485 input to the receiver. If your circuit is bi-directional you ...

    Jan 1, 1970