October 2009

Doc ID 8648 Rev 12

1/16

16

ST3243EB

ST3243EC

± 15 kV ESD protected 3 to 5.5 V, 400 kbps, RS-232

transceiver with auto power-down

Features

– ± 8 kV IEC 1000-4-2 contact discharge

– ± 15 kV human body model

power-down

Description

The ST3243E 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 communication standards providing

high data rate capability and enhanced

electrostatic discharge (ESD) protection. All

transmitter outputs and receiver input are

protected to ± 8 kV USING IEC 1000-4-2 contact

discharge and ± 15 kV using the human body

model. The receiver R2 is always active to

implement a wake-up feature for serial port.

The ST3243E has a proprietary low-dropout

transmitter output stage enabling true RS-232

performance from a 3.0 V to 5.5 V supply with a

dual charge pump. The device is guaranteed to

run at data rates of 250 kbps while maintaining

RS-232 output levels.

The auto 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, 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 1 µA.

Disconnecting the serial port or turning off the

peripheral drives causes the auto power-down

condition to occur.

Auto power-down can be disabled when

FORCEON and FORCEOFF are high, and should

be done when driving a serial mouse. With auto

power-down 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,

handheld equipment, peripherals and printers.

TSSOP

Table 1.

Device summary

Order codes

Temperature range

Package

Packaging

ST3243ECTR-E

0 to 70 °C

TSSOP28 (tape and reel)

2500 parts per reel

ST3243EBTR

- 40 to 85 °C

TSSOP28 (tape and reel)

2500 parts per reel

www.st.com