LT1280AISW#PBF

1
LT1280A/LT1281A
Low Power 5V RS232
Dual Driver/Receiver with
0.1µF Capacitors
R
Output Waveforms
LT1280A • TA02
DRIVER
OUTPUT
R
L
= 3k
C
L
= 2500pF
RECEIVER
OUTPUT
C
L
= 50pF
INPUT
S
F
EA
T
U
RE
D
U
ESCRIPTIO
The LT
®
1280A/LT1281A are dual RS232 driver/receiver
pairs with integral charge pump to generate RS232 volt-
age 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
120kbaud even while driving heavy capacitive loads. New
ESD structures on the chip allow the LT1280A/LT1281A to
survive multiple ±10kV strikes, eliminating the need for
costly TransZorbs
®
on the RS232 line pins. The LT1280A/
LT1281A 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 LT1281A is available in 16-pin DIP and SO packages.
The LT1280A 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
Portable Computers
Battery-Powered Systems
Power Supply Generator
Terminals
Modems
U
S
A
O
PP
L
IC
AT
I
U
A
O
PP
L
IC
AT
ITY
P
I
CA
L
5k
5k
0.1µF
0.1µF
0.1µF
0.1µF
LOGIC
INPUTS
LOGIC
OUTPUTS
ON/OFF
18
10
13
11
12
6
5
4
2
16
9
14
8
15
7
3
17
5V INPUT
V
+
OUT
V
OUT
RS232 OUTPUT
RS232 OUTPUT
RS232 INPUT
RS232 INPUT
LT1280A • TA01
LT1280A
+
+
+
+
10mA Max Supply Current
ESD Protection over ±10kV
Uses Small Capacitors: 0.1µF
120kBaud Operation for R
L
= 3k, C
L
= 2500pF
250kBaud Operation for R
L
= 3k, C
L
= 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
2
LT1280A/LT1281A
A
U
G
W
A
W
U
W
ARB
S
O
LU
T
EXI T
I
S
Supply Voltage (V
CC
) ................................................ 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 V
CC
+ 0.3V
Short-Circuit Duration
V
+
................................................................... 30 sec
V
................................................................... 30 sec
Driver Output.............................................. Indefinite
Receiver Output.......................................... Indefinite
Operating Temperature Range
LT1280AC/LT1281AC ............................. 0°C to 70°C
LT1280AI/LT1281AI .......................... –40°C to 85°C
Storage Temperature Range ................ 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
WU
U
PACKAGE
/
O
RDER I FOR ATIO
ORDER PART
NUMBER
ORDER PART
NUMBER
(Note 2)
E
LECTR
IC
AL C CHARA TERIST
ICS
Consult factory for Military grade parts.
1
2
3
4
5
6
7
8
9
TOP VIEW
18
17
16
15
14
13
12
11
10
NC
C1
+
V
+
C1
C2
+
C2
V
TR2 OUT
REC2 IN
N PACKAGE 18-LEAD PDIP
SW PACKAGE
18-LEAD PLASTIC SO WIDE
ON/OFF
V
CC
GND
TR1 OUT
REC1 IN
REC1 OUT
TR1 IN
TR2 IN
REC2 OUT
T
JMAX
= 125°C, θ
JA
= 80°C/W, θ
JC
= 36°C/W (N)
T
JMAX
= 125°C, θ
JA
= 90°C/W, θ
JC
= 26°C/W (SW)
LT1280ACN
LT1280AIN
LT1280ACSW
LT1280AISW
1
2
3
4
5
6
7
8
TOP VIEW
16
15
14
13
12
11
10
9
C1
+
V
+
C1
C2
+
C2
V
TR2 OUT
REC2 IN
V
CC
GND
TR1 OUT
REC1 IN
REC1 OUT
TR1 IN
TR2 IN
REC2 OUT
N PACKAGE 16-LEAD PDIP
SW PACKAGE
16-LEAD PLASTIC SO WIDE
T
JMAX
= 125°C, θ
JA
= 90°C/W, θ
JC
= 46°C/W (N)
T
JMAX
= 125°C, θ
JA
= 95°C/W, θ
JC
= 27°C/W (SW)
LT1281ACN
LT1281AIN
LT1281ACSW
LT1281AISW
(Note 1)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Power Supply Generator
V
+
Output 7.9 V
V
Output 7.0 V
Supply Current (V
CC
) (Note 3), T
A
= 25°C 8 10 mA
14 mA
Supply Current When OFF (V
CC
) Shutdown (Note 4) LT1280A Only 110 µA
Supply Rise Time C1 = C2 = C3 = C4 = 0.1µF 0.2 ms
Shutdown to Turn-On LT1280A Only 0.2 ms
ON/OFF Pin Thresholds Input Low Level (Device Shutdown)
0.8 1.2 V
Input High Level (Device Enabled) 1.6 2.4 V
ON/OFF Pin Current 0V V
ON/OFF
5V –15 80 µA
Oscillator Frequency 130 kHz
Driver
Output Voltage Swing Load = 3k to GND Positive
5.0 7.5 V
Negative
6.3 5.0 V
Logic Input Voltage Level Input Low Level (V
OUT
= High) 1.4 0.8 V
Input High Level (V
OUT
= Low) 2.0 1.4 V
3
LT1280A/LT1281A
Driver Output Voltage
TEMPERATURE (°C)
–55
–10
DRIVER OUTPUT VOLTAGE (V)
–8
–4
–2
0
10
4
0
50
75
LT1280A • TPC03
–6
6
8
2
–25
25
100
125
OUTPUT HIGH
OUTPUT LOW
R
L
= 3k
V
CC
= 5V
V
CC
= 4.5V
V
CC
= 5.5V
V
CC
= 4.5V
V
CC
= 5V
V
CC
= 5.5V
CCHARA TERIST
ICS
UW
AT
Y
P
I
CA
LPER
F
O
R
C
E
E
LECTR
IC
AL C CHARA TERIST
ICS
(Note 2)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Logic Input Current 0.8V V
IN
2.0V 520 µA
Output Short-Circuit Current V
OUT
= 0V ±917 mA
Output Leakage Current Shutdown V
OUT
= ±30V (Note 4) 10 100 µA
Data Rate (Note 7) R
L
= 3k, C
L
= 2500pF 120 kBaud
R
L
= 3k, C
L
= 1000pF 250 kBaud
Slew Rate R
L
= 3k, C
L
= 51pF 15 30 V/µs
R
L
= 3k, C
L
= 2500pF 4 7 V/µs
Propagation Delay Output Transition t
HL
High-to-Low (Note 5) 0.6 1.3 µs
Output Transition t
LH
Low-to-High 0.5 1.3 µs
Receiver
Input Voltage Thresholds Input Low Threshold (V
OUT
= High) C Grade 0.8 1.3 V
Input High Threshold (V
OUT
= Low) C Grade 1.7 2.4 V
Input Low I Grade 0.2 1.3 V
Input High I Grade
1.7 3.0 V
Hysteresis 0.1 0.4 1.0 V
Input Resistance V
IN
= ±10V 357 k
Output Leakage Current Shutdown (Note 4) 0 V
OUT
V
CC
110 µA
Output Voltage Output Low, I
OUT
= –1.6mA 0.2 0.4 V
Output High, I
OUT
= 160µA (V
CC
= 5V) 3.5 4.2 V
Output Short-Circuit Current Sinking Current, V
OUT
= V
CC
–20 –10 mA
Sourcing Current, V
OUT
= 0V 10 20 mA
Propagation Delay Output Transition t
HL
High-to-Low (Note 6) 250 600 ns
Output Transition t
LH
Low-to-High 350 600 ns
Note 4: Supply current measurements in shutdown are performed with
V
ON/OFF
0.1V.
Note 5: For driver delay measurements, R
L
= 3k and C
L
= 51pF. Trigger
points are set between the driver’s input logic threshold and the output
transition to the zero crossing (t
HL
= 1.4V to 0V and t
LH
= 1.4V to 0V).
Note 6: For receiver delay measurements, C
L
= 51pF. Trigger points are
set between the receiver’s input logic threshold and the output transition
to standard TTL/CMOS logic threshold (t
HL
= 1.3V to 2.4V and t
LH
= 1.7V
to 0.8V).
Note 7: Data rate operation guaranteed by slew rate, short-circuit current
and propagation delay tests.
The
denotes specifications which apply over the operating temperature
range (0°C T
A
70°C for commercial grade, and –40°C T
A
85°C for
industrial grade.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: Testing done at V
CC
= 5V and V
ON/OFF
= 3V, unless otherwise
specified.
Note 3: Supply current is measured as the average over several charge
pump cycles. C
+
= C
= C1 = C2 = 0.1µF. All outputs are open, with all
driver inputs tied high.
Driver Maximum Output Voltage
vs Load Capacitance
LOAD CAPACITANCE (nF)
0
5.0
PEAK OUTPUT VOLTAGE (V)
5.5
6.0
6.5
7.0
7.5
8.0
2468
LT1280A • TPC01
1013579
20k BAUD
60k BAUD
120k BAUD
Driver Minimum Output Voltage
vs Load Capacitance
LOAD CAPACITANCE (nF)
0
7.0
PEAK OUTPUT VOLTAGE (V)
6.5
6.0
5.5
5.0
4.5
4.0
2468
LT1280A • TPC02
1013579
120k BAUD
60k BAUD
20k BAUD

LT1280AISW#PBF

Mfr. #:
Manufacturer:
Analog Devices Inc.
Description:
RS-232 Interface IC L/P Dual 5V RS232, Dx/Rx, +/-10kV
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
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