• RS-232 Bus-Pin ESD Protection Exceeds ±15 kV Using Human-Body Model (HBM)
• Meets or Exceeds the Requirements of TIA/EIA-232-F and ITU V.28 Standards
• Operates With 3-V to 5.5-V VCC Supply
• Operates up to 250 kbps
• One Driver and One Receiver
• Low Standby Current: 1-μA Typical
• External Capacitors: 4 × 0.1 μF
• Accepts 5-V Logic Input With 3.3-V Supply
• Alternative High-Speed Pin-Compatible Device (1 Mbps)
  • SNx5C3221
• Automatic Power-Down Feature Automatically Disables Drivers for Power Savings

• Battery-Powered, Hand-Held, and Portable Equipment
• Notebooks, Subnotebooks, and Laptops
• Digital Cameras
• Mobile Phones and Wireless Devices

The TRS3221 device consists of one line driver, one line receiver with dedicated enable pin, and a dual charge-pump circuit with ±15-kV ESD protection pin-to-pin (serial-port connection pins, including GND). 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 one 3-V to 5.5-V supply. The TRS3221 device operates at data signaling rates up to 250 kbps 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 automatic power-down 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 and the supply current is reduced to 1 μA. The INVALID output notifies the user if an RS-232 signal is present at the receiver input.