SLLS792B June   2007  – July 2021 TRS3221E


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  6. Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  ESD Ratings, IEC Specifications
    4. 6.4  Recommended Operating Conditions
    5. 6.5  Thermal Information
    6. 6.6  Electrical Characteristics
    7. 6.7  Driver Section Electrical Characteristics
    8. 6.8  Driver Section Switching Characteristics
    9. 6.9  Receiver Section Electrical Characteristics
    10. 6.10 Receiver Section Switching Characteristics
    11. 6.11 Auto-Powerdown Section Electrical Characteristics
    12. 6.12 Auto-Powerdown Section Switching Characteristics
    13. 6.13 Typical Characteristics
  7. Parameter Measurement Information
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Power
      2. 8.3.2 RS232 Driver
      3. 8.3.3 RS232 Receiver
      4. 8.3.4 RS232 Status
    4. 8.4 Device Functional Modes
  9. Application Information Disclaimer
    1. 9.1 Application Information
    2. 9.2 Typical Application
    3. 9.3 Design Requirements
    4. 9.4 Detailed Design Procedure
    5. 9.5 Application Curve
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Support Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information


The TRS3221E is a single driver, single receiver RS-232 solution operating from a single VCC supply. The RS-232 pins provide IEC G1000-4-2 ESD protection. The device meets the requirements of TIA/EIA-232-F and provides the electrical interface between an asynchronous communication controller and the serial-port connector. The charge pump and four small external capacitors allow operation from a single 3-V to 5.5-V supply. These devices operate at data signaling rates up to 250 kbit/s and a maximum of 30-V/μs driver output slew rate.

Flexible control options for power management are available when the serial port is inactive. The auto-powerdown feature functions when FORCEON is low and FORCEOFF is high. During this mode of operation, if the device does not sense a valid RS-232 signal on the receiver input, the driver output is disabled. If FORCEOFF is set low and EN is high, both the driver and receiver are shut off, and the supply current is reduced to 1 μA. Disconnecting the serial port or turning off the peripheral drivers causes the auto-powerdown condition to occur. Auto-powerdown can be disabled when FORCEON and FORCEOFF are high.

With auto-powerdown enabled, the device is activated automatically when a valid signal is applied to the receiver input. The INVALID output notifies the user if an RS-232 signal is present at the receiver input. INVALID is high (valid data) if the receiver input voltage is greater than 2.7 V or less than –2.7 V, or has been between –0.3 V and 0.3 V for less than 30 μs. INVALID is low (invalid data) if the receiver input voltage is between –0.3 V and 0.3 V for more than 30 μs. Refer to Figure 7-5 for receiver input levels.

Device Information
TRS3221ESSOP (DB) (16)6.20 mm x 5.30 mm
TSSOP (PW) (16)5.00 mm × 4.40 mm

VQFN (RGT) (16)

3.00 mm x 3.00 mm

For all available packages, see the orderable addendum at the end of the data sheet.
GUID-0330A9C3-752E-4E90-86D2-CC9D995F8744-low.gif Simplified Schematic