1/11

May 2002

s

1

µA SUPPLY CURRENT ACHIEVED WHEN

IN AUTO-POWERDOWN

s

250Kbps MINIMUM GUARANTEED DATA

RATE

s

GUARANTEED 6V/

µs SLEW RATE RANGE

s

GUARANTEED MOUSE DRIVEABILITY

s

0.1

µF EXTERNAL CAPACITORS

s

MEET EIA/TIA-232 SPECIFICATIONS DOWN

TO 3V

s

AVAILABLE IN SO-28, SSOP-28 AND

TSSOP28

DESCRIPTION

The ST3243 device consists of 3 drivers, 5

receivers and a dual charge-pump circuit. The

device meets the requirements of EIA/TIA and

V.28/V.24 comunication standards providing high

data rate capability.

The receiver R2 is always active to implement a

wake-up feature for serial port.

The

ST3243

has

a

proprietary

low-dropout

transmitter output stage enabling true RS-232

performance from a 3.0V to 5.5V supply with a

dual charge pump. The device is guaranteed to

run at data rates of 250kbps while maintaining

RS-232 output levels.

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, the driver outputs are

disabled. If FORCEOFF is set low, both drivers

and receivers (expert R2B) are shut off, and

supply current is reduced to 1mA. Disconnecting

the serial port or turning off the peripheral drives

causes the auto-powerdown condition to occur.

Auto-powerdown

can

be

disabled

when

FORCEON and FORCEOFF are high, and should

be done when driving a serial mouse. With

Auto-powerdown enabled, the device is activated

automatically when a valid signal is applied to any

receiver input.

Typical application are in notebook, subnotebook,

palmtop computers, battery-powered equipment,

hand-held equipment, peripherals and printers.

ST3243

3 TO 5.5V, 400KBPS, RS-232

TRANSCEIVER WITH AUTO-POWERDOWN

SSOP

SOP

TSSOP