3 Description

The MAX3221 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 a single

3-V to 5.5-V supply. These devices operate 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.

1 Features

? 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

2 Applications

? Industrial PCs

? Wired networking

? Data center and enterprise computing

? Battery-powered systems

? PDAs

? Notebooks

? Laptops

? Palmtop PCs

? Hand-held equipment