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TRS3243
3-V TO 5.5-V MULTICHANNEL RS-232 LINE DRIVER/RECEIVER
WITH ±15-kV ESD (HBM) PROTECTION
SLLS806 – JUNE 2007
FEATURES
APPLICATIONS
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Single-Chip and Single-Supply Interface
for IBM™ PC/AT™ Serial Port
RS-232 Bus-Pin ESD Protection Exceeds
±15 kV Using Human-Body Model (HBM)
Meets or Exceeds the Requirements of
TIA/EIA-232-F and ITU v.28 Standards
Operates With 3-V to 5.5-V VCC Supply
Three Drivers and Five Receivers
Low Standby Current . . . 1 mA Typical
External Capacitors . . . 4 × 0.1 mF
Accepts 5-V Logic Input With 3.3-V Supply
Always-Active Noninverting Receiver
Output (ROUT2B)
Operating Speed
– TRS3243C, TRS3243I . . . 250 Kbit/s
– TRS3243FC, TRS3243FI . . . 1000 Kbit/s
Operating Temperature
– TRS3243C, TRS3243FC . . . 0°C to 70°C
– TRS3243I, TRS3243FI . . . –40°C to 85°C
Serial-Mouse Driveability
Auto-Powerdown Feature to Disable Driver
Outputs When No Valid RS-232 Signal Is
Sensed
Battery-Powered
Systems
PDAs
Notebooks
Laptops
Palmtop
PCs
Hand-Held Equipment
DB, DW, OR PW PACKAGE
(TOP VIEW)
C2+
C2−
V−
RIN1
RIN2
RIN3
RIN4
RIN5
DOUT1
DOUT2
DOUT3
DIN3
DIN2
DIN1
1
28
2
27
3
26
4
25
5
24
6
23
7
22
8
21
9
20
10
19
11
18
12
17
13
16
14
15
C1+
V+
VCC
GND
C1−
FORCEON
FORCEOFF
INVALID
ROUT2B
ROUT1
ROUT2
ROUT3
ROUT4
ROUT5
DESCRIPTION/ORDERING INFORMATION
The TRS3243 consists of three line drivers, five line receivers, and a dual charge-pump circuit with ±15-kV ESD
(HBM) protection pin to pin (serial-port connection pins, including GND). The device meets the requirements of
TIA/EIA-232-F and provides the electrical interface between an asynchronous communication controller and the
serial-port connector. This combination of drivers and receivers matches that needed for the typical serial port
used in an IBM PC/AT or compatible. The charge pump and four small external capacitors allow operation from
a single 3-V to 5.5-V supply. In addition, the device includes an always-active noninverting output (ROUT2B),
which allows applications using the ring indicator to transmit data while the device is powered down.
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.
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.
IBM, PC/AT are trademarks of IBM.
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
