Renesas' history with RS-232 and RS-485/422 transceivers dates back to the 1970s and we are still a market leader today. Whether it is a basic, low cost product or an enhanced product with added features, we have what our customers need for their next design.

Featured Products

Product Protocol Description Datasheet
RAA788152 RS-485/422 5V half-duplex, 0.115 Mbps RS-485/422 differential transceiver with ±5kV EFT immunity and ±16.5kV ESD protection pdf_icon_for_table.png
ISL3152E RS-485/422 5V full and half-duplex RS-485/422 transceivers with ±16.5kV ESD protection pdf_icon_for_table.png
ISL83080E RS-485/422 5V full and half-duplex RS-485/422 transceivers with full fail-safe and ±15kV ESD protection pdf_icon_for_table.png
ICL3221E RS-232 ±15kV ESD Protected, +3V to +5.5V, 1µA, 250kbps, RS-232 Transmitters/Receivers pdf_icon_for_table.png

Six Ways Renesas Enhances Your Serial Port

IEC 61000 Enhanced ESD Protection

Full-featured transceivers include improved ESD protection on bus pins that connect to an exposed port on a piece of equipment. Exposure makes the port susceptible to ESD events. Even connecting a charged interface cable could destroy an unprotected transceiver.

ESD protection falls under two standards: Human Body Model (HBM) standard and the IEC 61000-4-2 (IEC). The HBM test emulates the types of ESD events seen during manufacturing and handling, while the IEC ESD test is an end equipment test intended to harden equipment to ESD events seen in the field.

The special ESD structures utilized in Renesas' full-featured families allow these transceivers to meet the highest level for each of the standards.

Ruggedized Fault Protected: Overvoltage Protected (OVP)

Overvoltage protected, or fault protected, transceivers are designed so that the RS-485 bus pins can handle voltages much higher than those required by the RS-485 standard. This protects the device when power is routed in the same conduit as the data cable.

Intersil devices also feature a wide common mode voltage range (CMR) to compensate for the common mode voltage pick-up that occurs in long networks and noisy environments.

The ±16.5kV HBM ESD, the OVP and wide CMR features combined make the Renesas devices some of the most robust transceivers available.

High-Speed Transceivers

Applications like robotics, motor control and data acquisition require high data rates for minimal latency and increased throughput. Renesas' full-featured, high-speed family specifies the maximum Rx and Tx skews at 1.5ns, and the maximum part-to-part skew at 4ns.

  • ISL3179E (3V) and ISL3159E (5V) are specified at 40Mbps
  • ISL3259E (5V) operates at data rates up to 100Mbps
  • ISL3159E and ISL3259E have a Tx VOD > 2.1V (for high-speed PROFIBUS DP networks)
  • 125 °C option to compensate for high temperatures in motor control applications
  • MSOP and DFN packages available

Low Voltage & Low Power

Most current-generation RS-485 families have a “hot plug” function that disables the device when Vcc drops considerably below its nominal voltage (e.g., at 2.5V for Vcc = 3.3V), so 2.5V or 1.8V applications require ICs specifically designed for those operating voltages.

Single Tx (ISL32614E), Single Rx (ISL32610E), and Transceivers (ISL32602/603E) designed for low operating voltages:

  • Operate from voltages as low as 1.8V
  • Feature quiescent supply currents (Icc) as low as 80µA
  • Operate at data rates as high as 256kbps (Applications requiring higher data rates can use the ISL32603E or ISL32614E at 460kbps by powering them from a 3.3V supply)

Power critical applications such as remote sensor links and battery-operated security systems benefit from this level of performance.

Low-Cost Transceivers

Short, simple, low-node-count networks can often use low-cost RS-485 transceivers.

  • Short networks don't pick up much common mode voltage (CMV) and do not need more than the standard CMR or overvoltage protection (OVP).
  • Simple networks with ≤ 32 nodes do not require fractional unit load devices, and electrostatic discharge (ESD) protection may not be required. (Although some basic devices do include ±8kV to ±15kV Human Body Model ESD protection).
  • RS-422 networks with single, always enabled drivers, do not require bus biasing because the bus is constantly driven.
  • An electrically short bus does not need to be treated as a transmission line and does not require bus termination. (This may not apply in multi-driver systems).


Many applications need both an RS-232 and RS-485 serial port. The dual protocol devices integrate both transceivers into a single package. The single-channel device can be programmed for either interface. The two-channel configuration is very flexible as each channel can be either port.

Both 3.3V and 5V supply options are available. An in-line package and a more compact QFN package are available. The QFN package has additional features including a logic supply pin (VL) and selectable RS-485 data rates. The RS-232 data rate can operate up to 400kbps.


Title language Type Format File Size Date
EFT Immunity of the RAA78815x Family of 5V RS-485/RS-422 Transceivers Application Note PDF 472 KB
Analog ICs Brochure 日本語 Brochure PDF 2.72 MB
How to Simplify Industrial PC Interfaces 简体中文 White Paper PDF 920 KB
Dual Protocol Transceivers Ease the Design of Industrial Interfaces 简体中文 White Paper PDF 918 KB
Over-Voltage Protection for RS-485 Bus Nodes White Paper PDF 195 KB
RS-485 Transceiver Tutorial 简体中文 White Paper PDF 246 KB
Design Considerations for High-Speed RS-485 Data Links White Paper PDF 624 KB
RS-485 Isolator Raises the Bar for Bus Node Designs White Paper PDF 437 KB
Boost PROFIBUS RS-485 Robustness with GMR Isolation White Paper PDF 307 KB