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FEATURES

APPLICATIONS

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C2+

C2−

V−

RIN1

RIN2

RIN3

RIN4

RIN5

DOUT1

DOUT2

DOUT3

DIN3

DIN2

DIN1

C1+

V+

GND

C1−

FORCEON

FORCEOFF

INVALID

ROUT2B

ROUT1

ROUT2

ROUT3

ROUT4

ROUT5

DB, DW, OR PW PACKAGE

(TOP VIEW)

DESCRIPTION/ORDERING INFORMATION

TRSF3243

3-V TO 5.5-V MULTICHANNEL RS-232 COMPATIBLE LINE DRIVER/RECEIVER

• Operates With 3-V to 5.5-V V

• Always-Active Noninverting Receiver Output

(ROUT2B)

• Low Standby Current . . . 1 µA Typ

• External Capacitors . . . 4 × 0.1 µF

• Accepts 5-V Logic Input With 3.3-V Supply

• Inter-Operable With SN65C3238, SN75C3238

• Supports Operation From 250 kbit/s to

1 Mbit/s

• RS-232 Bus-Pin ESD Protection Exceeds

±15 kV Using Human-Body Model (HBM)

• Latch-Up Performance Exceeds 100 mA Per

JESD 78, Class II

• Battery-Powered Systems

• PDAs

• Notebooks

• Laptops

• Palmtop PCs

• Hand-Held Equipment

The TRSF3243 consists of three line drivers, five line receivers, and a dual charge-pump circuit with ±15-kV ESD

protection pin to pin (serial-port connection pins, including GND). This device 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. In addition, this device includes an

always-active noninverting output (ROUT2B), which allows applications using the ring indicator to transmit data

while the device is powered down. The device operates at data signaling rates up to 1 Mbit/s and an increased

slew-rate range of 24 V/

µs to 150 V/µs.

Flexible control options for power management are available when the serial port is inactive. 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 (except ROUT2B) 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.

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. The INVALID output is used to notify the user if an RS-232 signal is present at any

receiver input. INVALID is high (valid data) if any receiver input voltage is greater than 2.7 V or less than –2.7 V

or has been between –0.3 V and 0.3 V for less than 30

µs. INVALID is low (invalid data) if all receiver input

voltages are between –0.3 V and 0.3 V for more than 30

µs. Refer to Figure 5 for receiver input levels.

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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas

Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

PRODUCTION DATA information is current as of publication date.

Copyright © 2007–2008, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.