1 Features

• ESD Protection for RS-232 Pins

– ±15kV Human-Body Model (HBM)

– ±8kV (IEC 61000-4-2, contact discharge)

– ±15kV (IEC 61000-4-2, air-gap discharge)

• Meets or exceeds the requirements of TIA/

EIA-232-F and ITU v.28 standards

• Operates with 3V to 5.5V VCC supply

• Operates up to 250kbit/s

• One driver and one receiver

• Near chip-scale package, 16-pin VQFN (RGT, 82%

smaller than TSSOP package)

• Low standby current: 1μA Typical

• External capacitors: 4 × 0.1μF

• Accepts 5V logic input with 3.3V supply

• Alternative high-speed pin-compatible device

(1Mbit/s)

– TRSF3221E

• Auto-powerdown feature automatically disables

drivers for power savings

2 Applications

• Industrial PCs

• Wired networking

• Data center and enterprise computing

• Battery-powered systems

• PDAs

• Notebooks

• Laptops

• Palmtop PCs

• Hand-held equipment

3 Description

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 3V to 5.5V supply. These devices operate at

data signaling rates up to 250kbit/s and a maximum of

30V/μs driver output slew rate.

Flexible control options for power management are

available when the serial port is inactive. The autopowerdown

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. Autopowerdown

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 2.7V or less than –2.7V, or

has been between –0.3V and 0.3V for less than 30μs.

INVALID is low (invalid data) if the receiver input

voltage is between –0.3V and 0.3V for more than

30μs. Refer to Figure 6-5 for receiver input levels.