±15kV ESD-Protected, 1µA, 250kbps, 3.3V/5V, Dual RS-232 Transceivers with Internal Capacitors

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The MAX3233E/MAX3235E are EIA/TIA-232 and V.28/V.24 communications interfaces with automatic shutdown/wake-up features, high data-rate capabilities, and enhanced electrostatic discharge (ESD) protection. All transmitter outputs and receiver inputs are protected to ±15kV using IEC 1000-4-2 Air-Gap Discharge, to ±8kV using IEC 1000-4-2 Contact Discharge, and to ±15kV using the Human Body Model. The MAX3233E operates from a +3.3V supply; the MAX3235E operates from +5.0V.

All devices achieve a 1µA supply current using Maxim's revolutionary AutoShutdown Plus™ feature. These devices automatically enter a low-power shutdown mode when the following two conditions occur: either the RS-232 cable is disconnected or the transmitters of the connected peripherals are inactive, and the UART driving the transmitter inputs is inactive for more than 30 seconds. They turn on again when they sense a valid transition at any transmitter or receiver input. AutoShutdown Plus saves power without changes to the existing BIOS or operating system.

The MAX3233E/MAX3235E have internal dual charge pumps requiring no external capacitors. Both transceivers have a proprietary low-dropout transmitter output stage that enables true RS-232 performance from a +3.0V to +3.6V supply for the MAX3233E or a +4.5V to +5.5V supply for the MAX3235E. These devices are guaranteed to operate up to 250kbps. Both are available in space-saving 20-pin wide SO or plastic DIP packages.
MAX3233E, MAX3235E: Typical Operating Circuit MAX3233E, MAX3235E: Typical Operating Circuit Enlarge+

Key Features

  • ESD Protection for RS-232 I/O Pins
    • ±15kV—Human Body Model
    • ±8kV—IEC 1000-4-2, Contact Discharge
    • ±15kV—IEC 1000-4-2, Air-Gap Discharge
  • Latchup Free
  • 1µA Supply Current
  • AutoShutdown Plus-1997 EDN Magazine Innovation of the Year
  • Single-Supply Operation
    • +3.0V to +3.6V (MAX3233E)
    • +4.5V to +5.5V (MAX3235E)
  • 250kbps Guaranteed Data Rate
  • 6V/µs Guaranteed Slew Rate
  • Meets EIA/TIA-232 Specifications Down to 3.0V (MAX3233E)
  • Internal Charge-Pump Capacitors


  • Battery-Powered Applications
  • Cell Phones
  • Embedded Systems
  • Handheld Equipment
  • Peripherals
  • Subnotebook and Palmtop Computers
Part NumberVSUPPLY
TxRxData Rate
Internal Charge PumpExt. CapsESD Protect.
Rx Active in ShutdnPackage/PinsBudgetary
mintypSee Notes
MAX3233E 3.3222500.3Yes0152
$4.69 @1k
MAX3235E 5
$4.48 @1k
See All RS-232 Line Driver/Receivers (136)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Technical Documents

Tutorial 2141 Determining Clock Accuracy Requirements for UART Communications
Tutorial 739 Design Considerations for Data-Lump Cables

Quality and Environmental Data

Product Reliability Reports: MAX3233E.pdf 
Lead-Free Package Tin (Sn) Whisker Reports

Tools & Models

  • MAX3233E IBIS Model
  • CAD Symbols and Footprints

  • MAX3233ECWP+G36
  • MAX3233ECWP+TG36
  • MAX3233EEWP+G36
  • MAX3233EEWP+TG36
  • Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

    Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

    Quality Management System >
    Environmental Management System >


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