TRS3318_08 Datasheet, PDF (1/17 Pages) Texas Instruments – 2.5-V 460-kbps RS-232 TRANSCEIVER WITH ±15-kV ESD PROTECTION

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TRS3318
2.5-V 460-kbps RS-232 TRANSCEIVER
WITH ±15-kV ESD PROTECTION
SLLS820 – AUGUST 2007
FEATURES
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• 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
DB OR PW PACKAGE
(TOP VIEW)
READY 1
C1+ 2
V+ 3
C1− 4
C2+ 5
C2− 6
V− 7
DOUT2 8
RIN2 9
ROUT2 10
20 FORCEOFF
19 V_CC
18 GND
17 DOUT1
16 RIN1
15 ROUT1
14 FORCEON
13 DIN1
12 DIN2
11 INVALID
APPLICATIONS
• Battery-Powered Systems
• PDAs
• Cellular Phones
• Notebooks
• Hand-Held Equipment
• Pagers
DESCRIPTION/ORDERING INFORMATION
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.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2007, Texas Instruments Incorporated