+3.0V to +5.5V, 1µA, Up to 250kbps, True RS-232 Transceiver with AutoShutdown Plus

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The MAX3238 true RS-232 transceiver achieves a 1µA supply current with Maxim's revolutionary AutoShutdown Plus™ feature. When the device does not sense a valid signal transition on either the receiver or transmitter inputs within 30sec, the on-board power supply and drivers shut down. This occurs if the RS-232 cable is disconnected or if the transmitters of the connected peripheral are inactive. The system turns on again when a valid transition is applied to any RS-232 receiver or transmitter input, saving power without changes to the existing BIOS or operating system.

The MAX3238 5-driver/3-receiver complete serial port is a 3V-powered EIA/TIA-232 and V.28/V.24 communications interface intended for notebook or subnotebook computer applications. A proprietary, high-efficiency, dual charge-pump power supply and a low-dropout transmitter combine to deliver true RS-232 performance from a single +3.0V to +5.5V supply. A guaranteed data rate of 250kbps provides compatibility with popular software for communicating with personal computers. The MAX3238 requires only 0.1µF capacitors in 3.3V operation. It is ideal for 3.3V-only systems, mixed 3.3V and 5.0V systems, or 5V-only systems that require true RS-232 performance.

Receiver R1 has an extra, always-active output (in addition to its standard output), which allows external devices, such as a modem, to be monitored without forward biasing the protection diodes in circuitry that may have VCC completely removed.

The MAX3238 is available in a space-saving SSOP package.
MAX3238: Typical Operating Circuit MAX3238: Typical Operating Circuit Enlarge+

Key Features

  • 1µA Supply Current Achieved with AutoShutdown Plus
  • Guaranteed Data Rate: 250kbps
  • 1µA Low-Power Shutdown
  • Receivers Active in AutoShutdown Plus Mode
  • Flow-Through Pinout
  • Meets EIA/TIA-232 Specifications Down to 3.0V
  • Guaranteed 6V/µs Slew Rate
  • Auto shutdown reduces supply current to 1uA


  • Battery-Powered Applications
  • Handheld Equipment
  • High-Speed Modems
  • Notebook, Subnotebook, and Palmtop Computers
  • Peripherals
  • Printers
Part NumberVSUPPLY
TxRxData Rate
Internal Charge PumpExt. CapsCap. Value
Rx Active in ShutdnPackage/PinsBudgetary
mintypnomSee Notes
$3.85 @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 2020 Choosing the Right RS-232 Transceiver

Quality and Environmental Data

Product Reliability Reports: MAX3238.pdf 
Lead-Free Package Tin (Sn) Whisker Reports

Additional Resources

RS-232 Resources

CAD Symbols and Footprints

  • MAX3238CAI+
  • MAX3238CAI+T
  • MAX3238EAI+
  • MAX3238EAI+T
  • 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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