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FEATURES

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READY

C1+

V+

C1−

C2+

C2−

V−

DOUT2

RIN2

ROUT2

FORCEOFF

GND

DOUT1

RIN1

ROUT1

FORCEON

DIN1

DIN2

INVALID

DB OR PW PACKAGE

(TOP VIEW)

APPLICATIONS

DESCRIPTION/ORDERING INFORMATION

TRS3318

2.5-V 460-kbps RS-232 TRANSCEIVER

WITH ±15-kV ESD PROTECTION

SLLS820 – AUGUST 2007

www.ti.com

• ESD Protection for RS-232 I/O Pins

–

±15 kV Human-Body Model (HBM)

–

±8 kV IEC 61000-4-2, Contact Discharge

–

±8 kV IEC 61000-4-2, Air-Gap Discharge

• 300-μA Operating Supply Current

• 1-μA Low-Power Standby (With Receivers

Active) Mode

• Designed to Transmit at a Data Rate of

460 kbps

• Auto-Powerdown Plus Option Features

Flexible Power-Saving Mode

• Operates From a Single 2.25-V to 3-V V

CC

Supply

• Battery-Powered Systems

• PDAs

• Cellular Phones

• Notebooks

• Hand-Held Equipment

• Pagers

The

TRS3318

is

a

dual-driver,

dual-receiver,

RS-232

compatible

transceiver.

The

device

features

auto-powerdown plus and enhanced electrostatic discharge (ESD) protection integrated into the chip. Driver

output and receiver input are protected to ±8 kV using the IEC 61000-4-2 Air-Gap Discharge method, ±8 kV

using the IEC 61000-4-2 Contact Discharge method, and ±15 kV using the Human-Body Model (HBM).

The device operates at a data rate of 460 kbps. The transceiver has a proprietary low-dropout driver output stage

enabling RS-232-compatible operation from a 2.25-V to 3-V supply with a dual charge pump. The charge pump

requires only four 0.1-

μF capacitors and features a logic-level output (READY) that asserts when the charge

pump is regulating and the device is ready to begin transmitting.

The TRS3318 achieves a 1-

μA supply current using the auto-powerdown feature. This device automatically

enters a low-power power-down mode when the RS-232 cable is disconnected or the drivers of the connected

peripherals are inactive for more than 30 s. The device turns on again when it senses a valid transition at any

driver or receiver input. Auto-powerdown saves power without changes to the existing BIOS or operating system.

This device is available in two space-saving packages: 20-pin SSOP and 20-pin TSSOP.

Flexible control options for power management are featured when the serial port and driver inputs are inactive.

The auto-powerdown plus feature functions when FORCEON is low and FORCEOFF is high. During this mode of

operation, if the device does not sense valid signal transitions on all receiver and driver inputs for approximately

30 s, the built-in charge pump and drivers are powered down, reducing the supply current to 1

μA. By

disconnecting the serial port or placing the peripheral drivers off, auto-powerdown plus can be disabled when

FORCEON and FORCEOFF are high. With auto-powerdown plus enabled, the device activates automatically

when a valid signal is applied to any receiver or driver 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

(typical number). INVALID is low (invalid data) if all receiver input voltage are between –0.3 V and 0.3 V for more

than 30

μs (typical number).

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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, 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.