Intelligent +3.0V to +5.5V RS-232 Transceiver


  • Meets true EIA/TIA-232-F Standards from a +3.0V to +5.5V power supply
  • Interoperable with EIA/TIA-232 and adheres to EIA/TIA-562 down to a +2.7V power source
  • AUTO ON-LINE® circuitry automatically wakes up from a 1μA typical shutdown
  • Minimum 250kbps data rate under load
  • Regulated charge pump yields stable RS-232 outputs regardless of VCC variations
  • Enhanced ESD Specifications:
    • +15KV Human Body Model
    • +15KV IEC1000-4-2 Air Discharge
    • +8KV IEC1000-4-2 Contact Discharge

  • Low Power Serial Communications
  • Portable Serial Devices
  • Point of Sale Equipment
  • Embedded PCs

The SP3221E is a 1-driver/1-receiver RS-232 transceiver intended for portable or battery-powered applications such as embedded computers, data logging devices, medical diagnostics, and remote sensors. This device uses an internal high-efficiency, charge-pump power supply that requires only four 0.1µA capacitors. This charge pump and Exar's driver architecture allow the SP3221E to deliver compliant RS-232 performance from a single power supply ranging from +3.0V to +5.5V. The SP3221E is offered in a 16 pin TSSOP package.

The AUTO ON-LINE® feature allows the device to automatically "wake-up" during a shutdown state when an RS-232 cable is connected and a connected peripheral is turned on. Otherwise, the device automatically shuts itself down drawing less than 1µA.

For technical support or help choosing a product please email Exar’s Serial Technical Support group at:  serialtechsupport@exar.com.

Part NumberPkg CodeRoHSMin
StatusBuy NowOrder Samples

Part Status Legend
Active - the part is released for sale, standard product.
EOL (End of Life) - the part is no longer being manufactured, there may or may not be inventory still in stock.
CF (Contact Factory) - the part is still active but customers should check with the factory for availability. Longer lead-times may apply.
PRE (Pre-introduction) - the part has not been introduced or the part number is an early version available for sample only.
OBS (Obsolete) - the part is no longer being manufactured and may not be ordered.
NRND (Not Recommended for New Designs) - the part is not recommended for new designs. 
No. of Tx1
No. of Rx1
Data Rate (kbps)250
ESD (KV)15
Vcc MIN. (V)3
Vcc MAX. (V)5.5
TTL Tri-stateYes
Technical Assets