LT1080, LT1081
ADVANCED LOW-POWER
5-V DUAL EIA-232 DRIVER/RECEIVERS
SLLS050A – D3121, SEPTEMBER 1989 – REVISED FEBRUARY 1991
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Copyright 1991, Texas Instruments Incorporated
2–1
•Operates With Single 5-V Power Supply
•Generates ±9-V Supply Voltages With Only
1-µF Capacitors
•Designed to Avoid Latch-Up
•CMOS Comparable Low Power...60 mW
•Features Superior to CMOS:
Improved Speed...Operates Over
64K Baud
Improved Protection...Outputs Can Be
Forced to ±30 V Without Damage
3-State Outputs Are at High Impedance
When Off
•Power Additional EIA-232 Drivers...10 mA
•1-µA Supply Current in Shutdown
•Available With or Without Shutdown
•Suitable for ANSI/EIA-232-D-1986
Applications (Revision of EIA Std
RS-232-C)
•Designed to Be Interchangeable With
Linear Technology LT1080 and LT1081
description
The L T1080 and LT1081 are dual driver/receivers that include a charge pump to supply EIA-232 voltage levels
from a single 5-V supply. These interface-optimized devices are designed to avoid latch-up and provide a
realistic balance between CMOS levels of power dissipation and real-world requirements for ruggedness. The
driver outputs are fully protected against overload and can be shorted to ±30 V. Unlike CMOS devices, the
advanced architecture of the LT1080 and LT1081 does not load the signal line when shut down or when the
power is off. Both the receiver and EIA-232 outputs are put into a high-impedance state. An advanced output
stage allows driving higher capacitive loads at higher speeds with exceptional resistance to ESD.
Applications for these devices include portable computers, battery-powered EIA-232 systems, power-supply
generators, terminals, and modems.
The LT1080C and LT1081C are characterized for operation from 0°C to 70°C. The LT1080I and LT1081I are
characterized for operation from –40°C to 85°C.
1
2
3
4
5
6
7
8
9
18
17
16
15
14
13
12
11
10
NC
C1 +
VS+
C1 –
C2 +
C2 –
VS–
T2OUT
R2IN
ON/OFF
VCC
GND
T1OUT
R1IN
R1OUT
T1IN
T2IN
R2OUT
LT1080C, LT1080I . . . DW OR N PACKAGE
(TOP VIEW)
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
C1 +
VS+
C1 –
C2 +
C2 –
VS–
T2OUT
R2IN
VCC
GND
T1OUT
R1IN
R1OUT
T1IN
T2IN
R2OUT
LT1081C, LT1081I . . . DW OR N PACKAGE
(TOP VIEW)
NC – No internal connection
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
LT1080, LT1081
ADVANCED LOW -POWER
5-V DUAL EIA-232 DRIVER/RECEIVERS
SLLS050A – D3121, SEPTEMBER 1989 – REVISED FEBRUARY 1991
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
2–2
logic symbols†
LT1081LT1080
VCC
16
1
3
4
5
11
10
12
9
T1IN
R1OUT
R2OUT
2
6
14
7
13
8
15
0 V
GND
GND
0 V
16
R2IN
R1IN
T2OUT
T1OUT
VS+
9
14
8
15
7
3
R2OUT
R1OUT
T2IN
T1IN
ON/OFF
C2–
C2+
C1–
C1+
10
13
11
12
18
6
5
4
2
–1.7 VCC
1.8 VCC
CX2–
CX2+
CX1–
CX1+
EN
17
VCC
R2IN
R1IN
T2OUT
T1OUT
C2–
C2+
C1–
C1+
VS–
VS+
VCC VCC
–1.7 VCC
1.8 VCC
CX2–
CX2+
CX1–
CX1+
T2IN
VS–
†These symbols are in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
Terminal Functions
PIN
I/O
DESCRIPTION
NAME NO.†
I/O
DESCRIPTION
C1 +
C1 – 2 [1]
4 [3] External capacitor C1
C2 +
C2 – 5 [4]
6 [5] External capacitor C2
GND 16 [15] Ground pin
ON/OFF 18 I Controls the operation mode and is TTL/CMOS compatible. A low logic level places the device in the shutdown
mode, which reduces input supply current to near zero and places both driver and receiver outputs in a
high-impedance state. This input is not available on the LT1081.
R1IN 14 [13] I Receiver input. Accepts EIA-232 voltage levels (±30 V) and has hysteresis to provide noise immunity.
R2IN 9 [8] I Same as R1IN
R1OUT 13 [12] O Receiver output with TTL/CMOS voltage levels. Output is in a high-impedance state when in the shutdown
mode or when VCC = 0 to allow bus operation. Fully short-circuit protected to GND or VCC with power on, power
off, or in the shutdown mode.
R2OUT 10 [9] O Same as R1OUT
T1IN 12 [11] I EIA-232 driver input pin. Input is TTL/CMOS compatible. Unused inputs should be tied to VCC.
T2IN 11 [10] I Same as T1IN
T1OUT 15 [14] O Driver output with EIA-232 voltage levels. Outputs are in a high-impedance state when in the shutdown mode
or when VCC = 0 to allow bus operation. Fully short-circuit protected to GND or VCC with power on, power off,
or in the shutdown mode.
T2OUT 8 [7] O Same as T1OUT
VS+ 3 [2] Positive supply for EIA-232 drivers. Requires an external capacitor (1-µF) for charge storage.
VS– 7 [6] Negative supply for EIA-232 drivers. Requires an external capacitor (1-µF) for charge storage.
VCC 17 [16] Input supply pin. Supply current drops to near zero in the shutdown mode. Driver and receiver outputs are
in a high-impedance state when VCC = 0.
†Pin numbers in brackets are for the LT1081.
LT1080, LT1081
ADVANCED LOW -POWER
5-V DUAL EIA-232 DRIVER/RECEIVERS
SLLS050A – D3121, SEPTEMBER 1989 – REVISED FEBRUARY 1991
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 2–3
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, VCC (see Note 1) 6 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Positive output supply voltage 12 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Negative output supply voltage –12 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage range: Driver ±12 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Receiver ±30 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ON/OFF GND to 12 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output voltage range: T1OUT, T2OUT VS– + 30 V to VS+ – 30 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
R1OUT, R2OUT –0.3 V to VCC + 0.3 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Duration of output short circuit at (or below) 25°C: VS+ 30 s. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VS– 30 s. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driver or receiver output unlimited. . . . . . . . . . . . . . . . . . .
Continuous total dissipation See Dissipation Rating Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating free-air temperature range: LT1080C, LT1081C 0°C to 70°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LT1080I, LT1081I –40°C to 85°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage temperature range –65°C to 150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds 260°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
NOTE 1: All voltage values are with respect to network ground terminal.
DISSIPATION RATING TABLE
PACKAGE TA ≤ 25°C
POWER RATING DERATING FACTOR
ABOVE TA = 25°CTA = 70°C
POWER RATING TA = 85°C
POWER RATING
DW 1025 mW 8.2 mW/°C 656 mW 533 mW
N 1150 mW 9.2 mW/°C 736 mW 598 mW
recommended operating conditions
LT1080C, LT1081C LT1080I, LT1081I
UNIT
MIN TYP MAX MIN TYP MAX
UNIT
Supply voltage, VCC 4.5 5 5.5 4.5 5 5.5 V
High-level input voltage, VIH (T1IN, T2IN) 2 5.5 2 5.5 V
Low-level input voltage, VIL (T1IN, T2IN) 0.8 0.8 V
Operating free-air temperature, TA0 70 –40 85 °C
LT1080, LT1081
ADVANCED LOW -POWER
5-V DUAL EIA-232 DRIVER/RECEIVERS
SLLS050A – D3121, SEPTEMBER 1989 – REVISED FEBRUARY 1991
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
2–4
electrical characteristics over recommended ranges of supply voltage and operating free-air
temperature, VI = 3 V (unless otherwise noted)
driver section
PARAMETER TEST CONDITIONS MIN TYP†MAX UNIT
VOM+ Positive-peak output voltage RL = 3 kΩ to GND 5 7.5 V
VOM– Negative-peak output voltage RL = 3 kΩ to GND –5 –6.5 V
IIH High-level input current VI = 2 V to 5.5 V 5 20 µA
IIL Low-level input current VI ≤ 0.8 V –5 –20 µA
IOHS Output short-circuit current (sourcing) VI = 0, VO = 0, TA = 25°C–7 12 mA
IOLS Output short-circuit current (sinking) VI = 2 V, VO = 0, TA = 25°C 7 –12 mA
IOZ High-impedance output current Shutdown mode, VO = ±30 V 100 µA
receiver section
PARAMETER TEST CONDITIONS MIN TYP†MAX UNIT
VT
Positive going in
p
ut threshold voltage
LT1080C, LT1081C 1.7 2.4
V
V
T+
Positi
v
e
-
going
inp
u
t
threshold
v
oltage
LT1080I, LT1081I 1.7 3
V
VT
Negative going in
p
ut threshold voltage
LT1080C, LT1081C 0.8 1.3
V
V
T–
Negati
v
e
-
going
inp
u
t
threshold
v
oltage
LT1080I, LT1081I 0.2 1.3
V
Vhys Input hysteresis 0.1 0.4 1 V
riInput resistance TA = 25°C 3 5 7 kΩ
VOH High-level output voltage IOH = –160 µA, VCC = 5 V 3.5 4.8 V
VOL Low-level output voltage IOL = 1.6 mA 0.2 0.4 V
IOSH Output short-circuit current (sourcing) VI = 3 V, VO = 0, TA = 25°C –0.6 –1 mA
IOSL Output short-circuit current (sinking) VI = 3 V, VO = VCC, TA = 25°C 10 20 mA
IOZ High-impedance output current Shutdown mode, VO = 0 to VCC 10 µA
power supply section, VCC = 5 V, driver outputs low (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP†MAX UNIT
IS = 0, TA = 25°C 8 9
VS+ Supply output voltage IS = 10 mA, TA = 25°C 7 8 V
IS = 15 mA, TA = 25°C 6.5 7.5
IS = 0, TA = 25°C –7.5 –8.5
VS– Supply output voltage IS = 10 mA, TA = 25°C –5.5 –6.5 V
IS = 15 mA, TA = 25°C–5 –6
ICC Supply current 10 22 mA
ICC(off) Off-state supply current (LT1080) ON/OFF at 0.4 V 100 µA
II
In
p
ut current (ON/OFF) (LT1080)
VI = 5 V 80
µA
I
I
Inp
u
t
c
u
rrent
(ON/OFF)
(LT1080)
VI = 0 V –15 µ
A
†All typical values are at VCC = 5 V, TA = 25°C.
operating characteristics over recommended range of supply voltage, VI = 3 V, TA = 25°C
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
SR Driver slew rate RL = 3 kΩ to 7 kΩ, CL = 560 pF, See Note 2 4 15 30 V/µs
tr(supply) Supply rise time (see Note 3) C1–C4 = 1 µF 1 ms
NOTES: 2. Meets EIA-232-D specifications for capacitive loads greater than 560 pF.
3. Time from either shutdown input ON/OFF (LT1080) goes active high or VCC power on (LT1081) until the output voltages reach
VS+ ≥6 V and VS– ≤ –6 V.
LT1080, LT1081
ADVANCED LOW -POWER
5-V DUAL EIA-232 DRIVER/RECEIVERS
SLLS050A – D3121, SEPTEMBER 1989 – REVISED FEBRUARY 1991
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 2–5
TYPICAL CHARACTERISTICS†
– 4
– 8
6
– 10
– 50 – 25 0 25 50
– Driver Output Voltage – V
2
– 2
4
HIGH- AND LOW-LEVEL
DRIVER OUTPUT VOLTAGE
vs
FREE-AIR TEMPERATURE
10
75 100 125
8
0
– 6
VCC = 5.5 V
VCC = 5 V VCC = 4.5 V
Output High
RL = 3 kΩ
VCC = 4.5 V
VCC = 5.5 V
VCC = 5 V
Output Low
VO
TA – Free-Air Temperature – °C
0.4
0.1
10
–50 –25 0 25 50 100
– High-Impedance Output Current –
HIGH-IMPEDANCE
DRIVER OUTPUT CURRENT
vs
FREE-AIR TEMPERATURE
75 125
4
1
IOZ Aµ
Shutdown Mode
VO = 30 V VO = – 30 V
TA – Free-Air Temperature – °C
Figure 1 Figure 2
1.25
0.75
2.5
0.5
– 50 – 25 0 25 50
– Input Threshold Voltage – V
2
1.5
2.25
POSITIVE-GOING AND NEGATIVE-GOING
RECEIVER INPUT THRESHOLD VOLTAGE
vs
FREE-AIR TEMPERATURE
3
75 100 125
2.75
1.75
1
VT
TA – Free-Air Temperature – °C
VT+
VT–
0.1
100
– 50 – 25 0 25 50 100
Source or Sink Current – mA
RECEIVER SOURCE CURRENT
AND SINK CURRENT
vs
FREE-AIR TEMPERATURE
75 125
10
1
TA – Free-Air Temperature – °C
IOLS (sinking)
IOHS (sourcing)
Figure 3 Figure 4
†Data at high and low temperatures are applicable only within the rated operating free-air temperature ranges of the various devices.
LT1080, LT1081
ADVANCED LOW -POWER
5-V DUAL EIA-232 DRIVER/RECEIVERS
SLLS050A – D3121, SEPTEMBER 1989 – REVISED FEBRUARY 1991
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
2–6
TYPICAL CHARACTERISTICS†
0
–2
–6
–8
–10
8
–4
0 2 4 6 8 10 12
Supply Output Voltage – V
4
2
6
SUPPLY OUTPUT VOLTAGE
vs
OUTPUT CURRENT
10
14 16 18 20
VS+
VS–
Loaded to VS–
Loaded to VS+
Loaded to GND
Loaded to GND
IO – Output Current – mA
0
–2
–6
–8
–10
8
–4
0 0.2 0.4 0.6 0.8 1 1.2
Supply Output Voltage – V
4
2
6
t – Time – ms
SUPPLY OUTPUT VOLTAGE
vs
ELAPSED TIME
10
1.4 1.6 1.8 2
VS+
VS–
VCC = 5 V
C1 – C4 = 1 µF
RL = 4.7 kΩ
VCC = 5 V
Figure 5 Figure 6
15
10
0
–5
–10
35
5
012345
– Input Current –
25
20
30
ON/OFF INPUT CURRENT
vs
INPUT VOLTAGE
40
IIAµ
VI – Input Voltage – V
1.5
0.5
4
0
– 50 – 25 0 25 50
– Input Voltage – V
3
2
3.5
ON/OFF INPUT VOLTAGE
vs
FREE-AIR TEMPERATURE
5
75 100 125
4.5
2.5
1
VI
Min On Voltage
Max Off Voltage
TA – Free-Air Temperature – °C
Figure 7 Figure 8
†Data at high and low temperatures are applicable only within the rated operating free-air temperature ranges of the various devices.
LT1080, LT1081
ADVANCED LOW -POWER
5-V DUAL EIA-232 DRIVER/RECEIVERS
SLLS050A – D3121, SEPTEMBER 1989 – REVISED FEBRUARY 1991
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 2–7
TYPICAL CHARACTERISTICS†
4
1
10
–50 0 7525 50 100 125
– Off-State Supply Current – nA
OFF-STATE SUPPLY CURRENT
vs
FREE-AIR TEMPERATURE
2
7
VCC = 5 V
CC(off)
I
–25
T
A
– Free-Air Temperature – °C
5
0
0
012345
–5
5
DRIVER and RECEIVER
PULSE RESPONSE
6789
5
0
Receiver Output Driver OutputInput
Voltage Voltage – V Voltage – V
t – Time – µs
VCC = 5 V
RL = 3 kΩ
CL = 51 pF
TA = 25°C
–5
10
Figure 9 Figure 10
–5
–10
0
0 0.5 1 1.5 2 2.5
0
5
t – Time – ms
ON/OFF TO DRIVER OUTPUT
PULSE RESPONSE
10
3 3.5 4 4.5
5
0
VCC = 5 V
RL = 3 kΩ
TA = 25°C
ON/OFF Low-Level Output High-Level Output
Voltage Voltage – V Voltage – V
0
0
0 0.5 1 1.5 2 2.5
2
6
t – Time – ms
ON/OFF TO RECEIVER
PULSE RESPONSE
3 3.5 4 4.5
5
4
VCC = 5 V
TA = 25°C
ON/OFF High-Level Output
Voltage Voltage – V
8
10
–5
–5
Figure 11 Figure 12
†Data at high and low temperatures are applicable only within the rated operating free-air temperature ranges of the various devices.
LT1080, LT1081
ADVANCED LOW -POWER
5-V DUAL EIA-232 DRIVER/RECEIVERS
SLLS050A – D3121, SEPTEMBER 1989 – REVISED FEBRUARY 1991
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
2–8
APPLICATION INFORMATION
The driver output stage of the LT1080 offers significantly improved protection over older bipolar and CMOS designs
(see Figures 13 and 14). In addition to limiting current, the driver output can be externally forced to ±30 V without
damage, excessive current flow , or supply disruption. Some drivers have diodes connected between the outputs and
the supplies, allowing externally applied voltages to cause excessive supply voltage to develop.
Externally Forced
Output Can Be
– 30 V
30 V
V–
V+
the Supplies
Voltage Can Force
Externally Applied
With Some Drivers,
Figure 13. LT1080/LT1081 Driver Figure 14. Older EIA-232 Drivers
and CMOS Drivers
Placing the L T1080 in the shutdown mode (pin 18 low) puts both the driver and receiver outputs in a high-impedance
state. This allows for bus operation and transceiver applications (see Figures 15–17). The shutdown mode also drops
input supply current (VCC) to near zero for power-conscious systems.
Input
(channel select)
ON/OFF
Input B
EIA-232
Input A
EIA-232
Output
Logic
Inverter
Logic
Receiver 2
LT1080
Receiver 1
LT1080
Logic
Logic
Line
Transmission
EIA-232
Driver 2
Driver 1
Input
(channel select)
ON/OFF
Input B
Input A
Inverter
Logic
LT1080
LT1080
Figure 15. Sharing a Receiver Line Figure 16. Sharing a Transmitter Line
LT1080, LT1081
ADVANCED LOW -POWER
5-V DUAL EIA-232 DRIVER/RECEIVERS
SLLS050A – D3121, SEPTEMBER 1989 – REVISED FEBRUARY 1991
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 2–9
APPLICATION INFORMATION
(transmit/receive)
ON/OFF
Line
Transmit/Receive
Logic
Line
Transmit/Receive
EIA-232
Receiver 2
Driver 1
Inverter
Logic
LT1080
LT1080
Figure 17. Transceiver
To protect against receiver input overloads in excess of ±30 V, a voltage clamp can be placed on the data line and
still maintain EIA-232 compatibility (see Figure 18).
When driving CMOS logic from a receiver that will be used in the shutdown mode and when there is no other active
receiver on the line, a 51-kΩ resistor can be placed from the logic input to VCC to force a definite logic level when the
receiver output is in a high-impedance state (see Figure 19).
The generated driver supplies (VS+ and VS–) may be used to power external circuitry such as other EIA-232 drivers
or operational amplifiers (see Figure 20). They should be loaded with care, since excessive loading can cause the
generated supply voltages to drop, causing the EIA-232 driver output voltages to fall below EIA-232 requirements.
See Figure 5 for a comparison of generated supply voltage versus supply current.
NOTE A: A PTC thermistor will allow continuous overload of
greater than ±100 V. NOTE A: Forces logic input state when VI is low.
Input
EIA-232 (see Note A)
1 kΩ
30 V
30 V 5 kΩOutput
Logic
ON/OFF
Input
EIA-232
Receiver
LT1080
Logic
CMOS
Output
Logic
VCC
(see Note A)
51 kΩ
Figure 18. Input Overload Protection Figure 19. Forcing a Definite Logic Level
LT1080, LT1081
ADVANCED LOW -POWER
5-V DUAL EIA-232 DRIVER/RECEIVERS
SLLS050A – D3121, SEPTEMBER 1989 – REVISED FEBRUARY 1991
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
2–10
APPLICATION INFORMATION
Op Amp
External
1 µF+
LT1080
VS–
V
S+
+
3
7
V
CC –
VCC +
–
+
GND
Driver
1 µF
16
Figure 20. Powering External Circuitry
17
EIA-232 In
Shutdown
C1
1 µF+
+6
5
4
2
LT1080
TTL Out
TTL Out
18 5 V
5 kΩ
EIA-232 In
EIA-232 Out
VS+
V
S– ++
7
3
TTL Out
TTL Out
TTL Out
TTL In
17 18
GND
VCC
ON/OFF LT1039
10
9
1
GND
30 kΩ
TTL In
TTL In
†
1 µF
5 kΩ
EIA-232 Out
EIA-232 In
TTL In
TTL In
EIA-232 Out
EIA-232 Out
EIA-232 Out
EIA-232 In
EIA-232 In
1 µF1 µF
16
VCC ON/OFF
VS+
V
S–
30 kΩ
30 kΩ
C1 +
C1 –
C2 +
C2 –
†In applications in which a separate second positive supply is available (such as 5 V and 12 V), the 12-V supply may be connected to pin 2 and
C1 deleted. The power circuitry will then invert the 12-V supply. The 5-V supply is still needed to power the biasing circuitry and receivers.
Figure 21. Supporting an LT1039 (Triple Driver/Receiver)
LT1080, LT1081
ADVANCED LOW -POWER
5-V DUAL EIA-232 DRIVER/RECEIVERS
SLLS050A – D3121, SEPTEMBER 1989 – REVISED FEBRUARY 1991
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 2–11
APPLICATION INFORMATION
ON/OFF
12 V Input
16
9
14
8
15
VO = – 12 V
7
3
17 5 V Input
+
18
10
13
11
C2 –
C2 +
2
4
5
6
12
1 µF+
LT1080
TTL In
TTL Out
TTL Out
5 kΩ
EIA-232 In
EIA-232 Out
†
TTL In EIA-232 Out
EIA-232 In
1 µF
5 kΩ
†C1+ used on LT1081
Figure 22. Operating With 5 V and 12 V
LT1080, LT1081
ADVANCED LOW -POWER
5-V DUAL EIA-232 DRIVER/RECEIVERS
SLLS050A – D3121, SEPTEMBER 1989 – REVISED FEBRUARY 1991
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
2–12
IMPORTANT NOTICE
Texas Instruments (TI) reserves the right to make changes to its products or to discontinue any semiconductor
product or service without notice, and advises its customers to obtain the latest version of relevant information
to verify, before placing orders, that the information being relied on is current and complete.
TI warrants performance of its semiconductor products and related software to the specifications applicable at
the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are
utilized to the extent TI deems necessary to support this warranty. Specific testing of all parameters of each
device is not necessarily performed, except those mandated by government requirements.
Certain applications using semiconductor products may involve potential risks of death, personal injury, or
severe property or environmental damage (“Critical Applications”).
TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, INTENDED, AUTHORIZED, OR WARRANTED
TO BE SUITABLE FOR USE IN LIFE-SUPPORT APPLICATIONS, DEVICES OR SYSTEMS OR OTHER
CRITICAL APPLICATIONS.
Inclusion of TI products in such applications is understood to be fully at the risk of the customer. Use of TI
products in such applications requires the written approval of an appropriate TI officer. Questions concerning
potential risk applications should be directed to TI through a local SC sales office.
In order to minimize risks associated with the customer’s applications, adequate design and operating
safeguards should be provided by the customer to minimize inherent or procedural hazards.
TI assumes no liability for applications assistance, customer product design, software performance, or
infringement of patents or services described herein. Nor does TI warrant or represent that any license, either
express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property
right of TI covering or relating to any combination, machine, or process in which such semiconductor products
or services might be or are used.
Copyright 1998, Texas Instruments Incorporated
