The ISL3332, ISL3333 are two port interface ICs where each port can be independently configured as a single RS-485/422 transceiver, or as a dual (2 Tx, 2 Rx) RS-232 transceiver. With both ports set to the same mode, two RS- 485/RS-422 transceivers, or four RS-232 transceivers are available. If either port is in RS-232 mode, the onboard charge pump generates RS-232 compliant ±5V Tx output levels from a single VCC supply as low as 3. 15V. The transceivers are RS-232 compliant, with the Rx inputs handling up to ±25V. In RS-485 mode, the transceivers support both the RS-485 and RS-422 differential communication standards. The receivers feature full failsafe operation, so the Rx outputs remain in a high state if the inputs are open or shorted together. The transmitters support up to three data rates, two of which are slew rate limited for problem free communications. The charge pump disables when both ports are in RS-485 mode, thereby saving power, minimizing noise, and eliminating the charge pump capacitors. Both RS-232 and RS-485 modes feature loopback and shutdown functions. Loopback internally connects the Tx outputs to the corresponding Rx input, to facilitate board level self test implementation. The outputs remain connected to the loads during loopback, so connection problems (e. g. , shorted connectors or cables) can be detected. Shutdown mode disables the Tx and Rx outputs, disables the charge pumps, and places the IC in a low current (35µA) mode. The ISL3333 is a QFN packaged device that includes two additional user selectable, lower speed and edge rate options for EMI sensitive designs, or to allow longer bus lengths. It also features a logic supply pin (VL) that sets the VOH level of logic outputs, and the switching points of logic inputs, to be compatible with another supply voltage in mixed voltage systems. The QFN also adds RS-232 mode Tx EN pins (DEN), and active low Rx enable pins (RXEN) to increase design flexibility. In RS-485 applications, active low Rx enable pins allow Tx/Rx direction control, via a single signal per port, by connecting the corresponding DE and RXEN pins together. For a single port version of these devices, please see the ISL3330, ISL3331 data sheet.


  • ±15kV (HBM) ESD Protected Bus Pins (RS-232 or RS-485)
  • Operates From a Single 3.3V Supply
  • Two Independent Ports, Each User Selectable for RS-232 (2 Transceivers) or RS-485/RS-422 (1 Transceiver)
  • True Flow-Through Pinouts Simplify Board Layouts
  • Pb-free (RoHS compliant)
  • Full Failsafe (Open/Short) Rx in RS-485/422 Mode
  • Loopback Mode Facilitates Board Self Test Functions
  • User Selectable RS-485 Data Rates (ISL3333 Only)
  • Fast Speed 20Mbps
  • Slew Rate Limited 460kbps
  • Slew Rate Limited 115kbps
  • Fast RS-232 Data Rate Up to 400kbps
  • RS-232 Tx and Rx Enable Pins (ISL3333 Only)
  • Small Charge Pump Caps 4 x 0.1µF
  • Low Current Shutdown Mode 35µA
  • QFN Package Saves Board Space (ISL3333 Only)
  • Logic Supply Pin (VL) Eases Operation in Mixed Supply Systems (ISL3333 Only)


  • Gaming Applications (eg, Slot Machines)
  • Single Board Computers
  • Factory Automation
  • Security Networks
  • Industrial/Process Control Networks
  • Level Translators (eg, RS-232 to RS-422)
  • Point of Sale Equipment
  • Dual Channel RS-485 Interfaces


Title language Type Format File Size Date
Datasheets & Errata
star ISL3332, ISL3333 Datasheet Datasheet PDF 1.50 MB
User Guides & Manuals
ISL3333EVAL1Z User Guide Guide PDF 696 KB
Application Notes & White Papers
R15AN0002: RS-485 Transient Protection in Industrial DC-Supply Buses Rev.1.00 Application Note PDF 178 KB
How to Simplify Industrial PC Interfaces 简体中文 White Paper PDF 920 KB
AN1991: Isolating RS-485 Interfaces with High-Speed Digital Optocouplers Application Note PDF 513 KB
AN1990: RS-485 Transceivers in J1708 Physical Layer Applications of Heavy Duty Vehicles Application Note PDF 826 KB
AN1987: RS-485 External Fail-Safe Biasing for Isolated Long Haul Buses Application Note PDF 443 KB
AN1986: External Fail-Safe Biasing of RS-485 Networks Application Note PDF 582 KB
AN1985: Transient Protection for the Standard RS-485 Transceiver: ISL3152E Application Note PDF 335 KB
AN1989: RS-422 vs RS-485: Similarities and Key Differences Application Note PDF 440 KB
AN1976: Important Transient Immunity Tests for RS-485 Networks Application Note PDF 338 KB
AN1977: Transient Voltage Suppressors: Operation and Features Application Note PDF 365 KB
AN1978: Surge Protection for Intersil's Standard RS-485 Transceivers Application Note PDF 369 KB
AN1979: Surge Protection simplified with Intersil's Overvoltage Protected (OVP) Transceivers Application Note PDF 500 KB
AN1980: Ground Potential Differences: Origin and Remedies Application Note PDF 375 KB
PCN15046 - Wafer Fabrication Site Change for Listed Intersil Products - Global Foundry P6 Process transfer to Palm Bay - Phase II Product Change Notice PDF 398 KB
PCN11116 - Alternate Manufacturing Site for Assembly of the Listed Intersil 28l SSOP Products - ANST (Wuxi CR Micro-Assembly Technology Ltd.) Product Change Notice PDF 180 KB
Analog ICs Brochure 日本語 Brochure PDF 4.20 MB
TB506: Functional Principles of RS-485 Drivers and Receivers Other PDF 156 KB
TB509: Detecting Bus Signals Correctly with Failsafe Biased RS-485 Receivers Technical Brief PDF 300 KB
TB513: Designing a 3-Wire, Half-Duplex, Dual Protocol Interface Using the ISL3330 and ISL3331 Technical Brief PDF 328 KB
TB511: The Unit Load Concept Other PDF 253 KB
TB508: Dual Protocol Applications: Programmable vs Standard Transceivers Other PDF 359 KB
TB507: Dual Protocol Transceivers Simplify Interface Design Other PDF 580 KB


Title language Type Format File Size Date
isl3332 Model - Other IBS 56 KB