FEATURES
LT1180A/LT1181A
Low Power 5V RS232
Dual Driver/Receiver with
0.1µF Capacitors
U
DESCRIPTIO
■
ESD Protection over ±10kV
■
Uses Small Capacitors: 0.1µF
■
120kBaud Operation for RL = 3k, CL = 2500pF
■
250kBaud Operation for RL = 3k, CL = 1000pF
■
Outputs Withstand ±30V Without Damage
■
CMOS Comparable Low Power: 40mW
■
Operates from a Single 5V Supply
■
Rugged Bipolar Design
■
Outputs Assume a High Impedance State When Off
or Powered Down
■
Meets All RS232 Specifications
■
Available With or Without Shutdown
■
Absolutely No Latch-up
■
Available in SO Package
U
APPLICATIO S
■
Portable Computers
■
Battery-Powered Systems
■
Power Supply Generator
■
Terminals
■
Modems
The LT®1180A/LT1181A are dual RS232 driver/receiver
pairs with integral charge pump to generate RS232 voltage levels from a single 5V supply. These circuits feature
rugged bipolar design to provide operating fault tolerance
and ESD protection unmatched by competing CMOS
designs. Using only 0.1µF external capacitors, these cir-
cuits consume only 40mW of power, and can operate to
120k baud even while driving heavy capacitive loads. New
ESD structures on the chip allow the LT1180A/LT1181A to
survive multiple ±10kV strikes, eliminating the need for
costly TransZorbs® on the RS232 line pins. The LT1180A/
LT1181A are fully compliant with EIA RS232 standards.
Driver outputs are protected from overload, and can be
shorted to ground or up to ±30V without damage. During
shutdown or power-off conditions, driver and receiver
outputs are in a high impedance state, allowing line
sharing.
The LT1181A is available in 16-pin DIP and SO packages.
The LT1180A is supplied in 18-pin DIP and SO packages
for applications which require shutdown.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TransZorb is a registered trademark of General Instruments, GSI
TYPICAL APPLICATIO
LOGIC
INPUTS
LOGIC
OUTPUTS
ON/OFF
0.1µF
0.1µF
2
+
4
LT1180A
5
+
6
12
11
13
10
18
17
3
7
15
8
14
5k
9
5k
16
U
5V INPUT
+
OUT
0.1µF
0.1µF
V
V– OUT
RS232 OUTPUT
RS232 OUTPUT
RS232 INPUT
RS232 INPUT
LT1180A • TA01
DRIVER
OUTPUT
RL = 3k
= 2500pF
C
L
RECEIVER
OUTPUT
R
CL = 50pF
INPUT
+
+
Output Waveforms
LT1180A • TA02
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1
LT1180A/LT1181A
A
W
O
LUTEXI TIS
S
A
WUW
U
(Note 1)
ARB
G
Supply Voltage (VCC) ................................................ 6V
V+........................................................................ 13.2V
V–...................................................................... –13.2V
Input Voltage
Driver ........................................................... V– to V
+
Receiver ............................................... – 30V to 30V
ON/OFF ................................................. – 0.3V to 12V
Output Voltage
Driver ...................................... V+ – 30V to V– + 30V
Receiver .................................... – 0.3V to VCC + 0.3V
PACKAGE
1
NC
+
2
C1
+
3
V
–
4
C1
+
5
C2
–
6
C2
–
7
V
TR2 OUT
REC2 IN
18-LEAD PDIP
T
T
T
JMAX
8
9
N PACKAGE
= 125°C, θ
JMAX
= 125°C, θ
JMAX
= 150°C, θJA = 100°C/W, θJC = 40°C/W (J)
/
O
RDER I FOR ATIO
TOP VIEW
ON/OFF
18
V
17
CC
GND
16
TR1 OUT
15
REC1 IN
14
REC1 OUT
13
TR1 IN
12
TR2 IN
11
REC2 OUT
10
SW PACKAGE
18-LEAD PLASTIC SO (WIDE)
= 80°C/ W, θJC = 36°C/W (N)
JA
= 90°C/ W, θJC = 26°C/W (SW)
JA
J PACKAGE
18-LEAD CERDIP
WU
ORDER PART
NUMBER
LT1180ACN
LT1180ACSW
LT1180AIN
LT1180AISW
LT1180AMJ
U
OBSOLETE PACKAGE
Consider N Package for Alternate Source
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Short-Circuit Duration
V+................................................................... 30 sec
V–................................................................... 30 sec
Driver Output.............................................. Indefinite
Receiver Output.......................................... Indefinite
Operating Temperature Range
LT1180AI/LT1181AI .......................... – 40°C to 85°C
LT1180AC/LT1181AC ............................. 0°C to 70°C
Storage Temperature Range ................ –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
TOP VIEW
+
1
C1
+
2
V
–
3
C1
+
4
C2
–
5
C2
–
6
V
TR2 OUT
REC2 IN
16-LEAD PDIP
T
T
7
8
N PACKAGE
T
JMAX
JMAX
= 150°C, θJA = 100°C/W, θJC = 40°C/W (J)
JMAX
16-LEAD PLASTIC SO (WIDE)
= 125°C, θ
= 125°C, θ
= 90°C/W, θJC = 46°C/W (N)
JA
= 95°C/ W, θJC = 27°C/W (SW)
JA
J PACKAGE
16-LEAD CERDIP
16
15
14
13
12
11
10
9
SW PACKAGE
V
CC
GND
TR1 OUT
REC1 IN
REC1 OUT
TR1 IN
TR2 IN
REC2 OUT
ORDER PART
NUMBER
LT1181ACN
LT1181ACSW
LT1181AIN
LT1181AISW
LT1181AMJ
OBSOLETE PACKAGE
Consider N Package for Alternate Source
LECTRICAL C CHARA TERIST
E
ICS
The ● denotes specifications which apply over the operating temperature
range (0°C ≤ TA ≤ 70°C for commercial grade, and –40°C ≤ TA ≤ 85°C for industrial grade. (Note 2)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Power Supply Generator
V+ Output 7.9 V
V– Output –7.0 V
Supply Current (V
Supply Current When OFF (VCC) Shutdown (Note 4) LT1180A Only ● 110 µA
Supply Rise Time C1 = C2 = C3 = C4 = 0.1µF 0.2 ms
Shutdown to Turn-On LT1180A Only 0.2 ms
ON/OFF Pin Thresholds Input Low Level (Device Shutdown) ● 0.8 1.2 V
) (Note 3), TA = 25°C913mA
CC
Input High Level (Device Enabled) ● 1.6 2.4 V
● 16 mA
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LT1180A/LT1181A
LECTRICAL C CHARA TERIST
E
range (0°C ≤ TA ≤ 70°C for commercial grade, and –40°C ≤ TA ≤ 85°C for industrial grade. (Note 2)
PARAMETER CONDITIONS MIN TYP MAX UNITS
ON/OFF Pin Current 0V ≤ V
Oscillator Frequency 130 kHz
Driver
Output Voltage Swing Load = 3k to GND Positive 5.0 7.5 V
Logic Input Voltage Level Input Low Level (V
Input High Level (V
Logic Input Current 0.8V ≤ VIN ≤ 2.0V ● 520 µA
Output Short-Circuit Current V
Output Leakage Current Shutdown V
Date Rate (Note 7) RL = 3k, CL = 2500pF 120 kBaud
Slew Rate RL = 3k, CL = 51pF 15 30 V/µs
= 3k, CL = 2500pF 47 V/µs
R
L
Propagation Delay Output Transition tHL High-to-Low (Note 5) 0.6 1.3 µs
Receiver
Input Voltage Thresholds Input Low Threshold (V
Hysteresis ● 0.1 0.4 1.0 V
Input Resistance VIN = ±10V 3 5 7 kΩ
Output Leakage Current Shutdown (Note 4) 0 ≤ V
Output Voltage Output Low, I
Output Short-Circuit Current Sinking Current, V
Propagation Delay Output Transition tHL High-to-Low (Note 6) 250 600 ns
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: Testing done at V
specified.
Note 3: Supply current is measured as the average over several charge
pump cycles. C
driver inputs tied high.
Note 4: Supply current measurements in SHUTDOWN are performed with
≤ 0.1V.
V
ON/OFF
= Low) ● 2.0 1.4 V
OUT
= 5V and V
CC
+
= C– = C1 = C2 = 0.1µF. All outputs are open, with all
ON/OFF
ON/OFF
= 0V ±917 mA
OUT
= 3k, CL = 1000pF 250 kBaud
R
L
Output Transition t
Input High Threshold (V
Input LowI, M Grade ● 0.2 1.3 V
Input HighI, M Grade
Output High, I
Sourcing Current, V
Output Transition t
= 3V, unless otherwise
ICS
≤ 5V ● –15 80 µA
= ±30V (Note 4) ● 10 100 µA
OUT
OUT
OUT
The ● denotes specifications which apply over the operating temperature
Negative
= High) ● 1.4 0.8 V
OUT
Low-to-High 0.5 1.3 µs
LH
= High) C Grade ● 0.8 1.3 V
OUT
= Low) C Grade ● 1.7 2.4 V
OUT
≤ V
OUT
CC
= –1.6mA ● 0.2 0.4 V
= 160µA (VCC = 5V) ● 3.5 4.2 V
= V
OUT
CC
= 0V 10 20 mA
OUT
Low-to-High 350 600 ns
LH
Note 5: For driver delay measurements, R
points are set between the driver’s input logic threshold and the output
transition to the zero crossing (t
Note 6: For receiver delay measurements, CL = 51pF. Trigger points are
set between the receiver’s input logic threshold and the output transition
to standard TTL/CMOS logic threshold (tHL = 1.3V to 2.4V and tLH = 1.7V
to 0.8V).
Note 7: Data rate operation guaranteed by slew rate, short-circuit current
and propagation delay tests.
● –6.3 –5.0 V
● 1.7 3.0 V
● 110 µA
–20 –10 mA
= 3k and CL = 51pF. Trigger
L
= 1.4V to 0V and tLH = 1.4V to 0V).
HL
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LT1180A/LT1181A
TEMPERATURE (°C)
–55
–10
DRIVER OUTPUT VOLTAGE (V)
–8
–4
–2
0
10
4
0
50
75
LT1180A • TPC03
–6
6
8
2
–25
25
100
125
OUTPUT HIGH
OUTPUT LOW
RL = 3k
VCC = 5V
V
CC
= 4.5V
V
CC
= 5.5V
VCC = 4.5V
V
CC
= 5V
V
CC
= 5.5V
LPER
F
O
R
ATYPICA
UW
CCHARA TERIST
E
C
ICS
Driver Maximum Output Voltage
vs Load Capacitance
8.0
7.5
7.0
6.5
6.0
PEAK OUTPUT VOLTAGE (V)
5.5
5.0
2468
0
LOAD CAPACITANCE (nF)
20kBAUD
60kBAUD
120kBAUD
Receiver Input Thresholds
3.00
2.75
2.50
2.25
2.00
1.75
1.50
1.25
THRESHOLD VOLTAGE (V)
1.00
0.75
0.50
–55
–25
INPUT HIGH
INPUT LOW
50
25
0
TEMPERATURE (°C)
75
LT1180A • TPC01
100
LT1180A • TPC04
1013579
125
Driver Minimum Output Voltage
vs Load Capacitance
–4.0
–4.5
–5.0
–5.5
–6.0
PEAK OUTPUT VOLTAGE (V)
–6.5
–7.0
0
120kBAUD
2468
LOAD CAPACITANCE (nF)
60kBAUD
20kBAUD
1013579
LT1180A • TPC02
Driver Output Voltage
Supply Current vs Data Rate ON/OFF Thresholds
50
2 DRIVERS ACTIVE
= 3k
R
L
= 2500pF
C
L
40
30
20
SUPPLY CURRENT (mA)
10
0
0
50 75 100
25
DATA RATE (kBAUD)
125 150
LT1180A • TPC05
3.0
2.5
2.0
1.5
1.0
THRESHOLD VOLTAGE (V)
0.5
0
–55
–25 0
ON THRESHOLD
OFF THRESHOLD
50 100 125
25 75
TEMPERATURE (°C)
LT1180A • TPC06
Supply Current
25
20
15
10
SUPPLY CURRENT (mA)
5
0
–55
4
–25
2 DRIVERS LOADED RL = 3k
1 DRIVER LOADED RL = 3k
NO LOAD
50
25
0
TEMPERATURE (°C)
75
100
LT1180A • TPC07
125
Driver Leakage in Shutdown
100
10
1
LEAKAGE CURRENT (µA)
0.1
–55 0
–25
V
OUT
25
TEMPERATURE (°C)
V
50
OUT
= 30V
= –30V
75
100
LT1180A • TPC08
125
Driver Short-Circuit Current
30
25
20
15
10
SHORT-CIRCUIT CURRENT (mA)
5
0
–55
–25 0
25 75
TEMPERATURE (°C)
+
I
SC
–
I
SC
50 100 125
LT1180A • TPC09
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