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1
LTC1382
5V Low Power
RS232 Transceiver
with Shutdown
S
FEATURE
D
U
ESCRIPTIO
s
Operates from a Single 5V Supply
s
Low Supply Current: I
CC
= 220
A
s
I
CC
= 0.2
A in Shutdown Mode
s
ESD Protection Over
10kV
s
Uses Small Capacitors: 0.1
F
s
Operates to 120kBaud
s
Output Overvoltage Does Not Force Current
Back into Supplies
s
RS232 I/O Lines Can Be Forced to
25V
Without Damage
s
Pin Compatible with LT1180A
The LTC1382 is an ultra-low power 2-driver/2-receiver
RS232 transceiver that operates from a single 5V
supply. The charge pump requires only four space-
saving 0.1
F capacitors.
The transceiver operates in one of two modes, Normal
and Shutdown. In the Normal mode, I
CC
is only 220
A
with the driver outputs unloaded. In the Shutdown
mode, the charge pump is turned off, the driver outputs
are forced into three-state, both receivers are off and
I
CC
drops to 0.2
A.
The LTC1382 is fully compliant with all data rate and
overvoltage RS232 specifications. The transceiver can
operate up to 120kbaud with a 2500pF, 3k
load. Both
driver outputs and receiver inputs can be forced to
25V without damage and can survive multiple
10kV
ESD strikes.
U
S
A
O
PPLICATI
s
Notebook Computers
s
Palmtop Computers
U
A
O
PPLICATI
TYPICAL
TEMPERATURE (C)
20
0
QUIESCENT CURRENT (
A)
100
200
300
400
600
0
20
40
60
LTC1382 TA02
80
500
TEST CONDITION: V
CC
= 5V
0
SHUTDOWN CURRENT (
A)
0.2
0.4
0.6
0.8
1.2
1.0
QUIESCENT
CURRENT
SHUTDOWN
CURRENT
Quiescent and Shutdown Supply Current
vs Temperature
2-Drivers/2-Receivers with Shutdown
LTC1382 TA01
LTC1382
2
4
0.1
F
17
V
CC
= 5V
3
0.1
F
7
0.1
F
0.1
F
5
6
232 OUTPUT
15
8
232 OUTPUT
300k
14
232 INPUT
5k
9
232 INPUT
16
12
11
13
10
LOGIC INPUT
LOGIC INPUT
LOGIC OUTPUT
LOGIC OUTPUT
300k
5k
18
ON/OFF
V
CC
V
CC
2
LTC1382
A
U
G
W
A
W
U
W
A
R
BSOLUTE
XI
TI
S
W
U
U
PACKAGE/ORDER I FOR ATIO
Supply Voltage (V
CC
) ................................................ 6V
Input Voltage
Driver ....................................... 0.3V to V
CC
+ 0.3V
Receiver ............................................... 25V to 25V
Digital Input ............................... 0.3V to V
CC
+ 0.3V
Output Voltage
Driver .................................................... 25V to 25V
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 .................... 0
C to 70
C
Storage Temperature Range ................ 65
C to 150
C
Lead Temperature (Soldering, 10 sec)................. 300
C
ORDER PART
NUMBER
LTC1382CN
LTC1382CS
ELECTRICAL C
C
HARA TERISTICS
C
D
T
JMAX
= 125
C,
JA
= 56
C/W (N)
T
JMAX
= 125
C,
JA
= 85
C/W (S)
1
2
3
4
5
6
7
8
9
TOP VIEW
S PACKAGE
18-LEAD PLASTIC SOL
18
17
16
15
14
13
12
11
10
NC
C1
+
V
+
C1
C2
+
C2
V
TR2 OUT
RX2 IN
ON/OFF
V
CC
GND
TR1 OUT
RX1 IN
RX1 OUT
TR1 IN
TR2 IN
RX2 OUT
N PACKAGE
18-LEAD PLASTIC DIP
Consult factory for Industrial and Military grade parts.
V
CC
= 5V, C1 = C2 = C3 = C4 = 0.1
F, V
ON/OFF
= V
CC
unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Any Driver
Output Voltage Swing
3k to GND
Positive
q
5.0
7.0
V
Negative
q
5.0
6.5
V
Logic Input Voltage Level
Input Low Level (V
OUT
= High)
q
1.4
0.8
V
Input High Level (V
OUT
= Low)
q
2.0
1.4
V
Logic Input Current
V
IN
= V
CC
q
5
A
V
IN
= 0V
q
20
40
A
Output Short-Circuit Current
V
OUT
= 0V
12
mA
Output Leakage Current
Shutdown or V
CC
= 0V (Note 3), V
OUT
=
20V
q
10
500
A
Any Receiver
Input Voltage Thresholds
Input Low Threshold
q
0.8
1.3
V
Input High Threshold
q
1.7
2.4
V
Hysteresis
q
0.1
0.4
1
V
Input Resistance
10V
V
IN
10V
3
5
7
k
Output Voltage
Output Low, I
OUT
= 1.6mA (V
CC
= 5V)
q
0.2
0.4
V
Output High, I
OUT
= 160
A (V
CC
= 5V)
q
3.0
3.2
V
Output Short-Circuit Current
Sinking Current, V
OUT
= V
CC
15
40
mA
Sourcing Current V
OUT
= 0V
10
20
mA
Output Leakage Current
Shutdown (Note 3), 0V
V
OUT
V
CC
q
1
10
A
3
LTC1382
ELECTRICAL C
C
HARA TERISTICS
C
D
V
CC
= 5V, C1 = C2 = C3 = C4 = 0.1
F, V
ON/OFF
= V
CC
, unless otherwise noted.
C
C
HARA TERISTICS
AC
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Power Supply Generator
V
+
Output Voltage
I
OUT
= 0mA
8.0
V
I
OUT
= 8mA
7.5
V
V
Output Voltage
I
OUT
= 0mA
8.0
V
I
OUT
= 8mA
7.0
V
Supply Rise Time
Shutdown to Turn-On
0.2
ms
Power Supply
V
CC
Supply Current
No Load (Note 2)
q
0.22
0.5
mA
Supply Leakage Current (V
CC
)
Shutdown (Note 3)
q
0.2
10
A
Digital Input Threshold Low
q
1.4
0.8
V
Digital Input Threshold High
q
2.0
1.4
V
V
CC
= 5V, C1 = C2 = C3 = C4 = 0.1
F, unless otherwise noted.
The
q
denotes specifications which apply over the operating temperature
range of 0
C
T
A
70
C.
Note 1: Absolute maximum ratings are those values beyond which the life
of the device may be impaired.
Note 2: Supply current is measured with driver and receiver outputs
unloaded.
Note 3: Measurements made in the Shutdown mode are performed
with V
ON/OFF
= 0V.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Slew Rate
R
L
= 3k, C
L
= 51pF
8
30
V/
s
R
L
= 3k, C
L
= 2500pF
3
5
V/
s
Driver Propagation Delay
t
HLD
(Figure 1)
q
2
3.5
s
(TTL to RS232)
t
LHD
(Figure 1)
q
2
3.5
s
Receiver Propagation Delay
t
HLR
(Figure 2)
q
0.3
0.8
s
(RS232 to TTL)
t
LHR
(Figure 2)
q
0.3
0.8
s
TYPICAL PERFOR
M
A
N
CE CHARACTERISTICS
U
W
Driver Output Voltage
vs Temperature
TEMPERATURE (C)
0
8
DRIVER OUTPUT VOLTAGE (V)
6
2
0
2
40
10
LTC1382 TPC01
4
20
10
50
60
30
70
4
6
8
R
L
= 3k
V
CC
= 5V
V
CC
= 4.5V
OUTPUT HIGH
V
CC
= 4.5V
V
CC
= 5V
OUTPUT LOW
DATA RATE (kBAUD)
0
0
SUPPLY CURRENT (mA)
5
15
20
25
100
45
LTC1382 TPC03
10
50
25
125
75
150
175
30
35
40
V
CC
= 5V
R
L
= 3k
C
L
= 2500pF
2 DRIVERS ACTIVE
TEMPERATURE (C)
0
THRESHOLD VOLTAGE (V)
1.8
2.0
2.2
30
50
V
TH
V
TL
LTC1382 TPC02
1.6
1.4
10
20
40
60
70
1.2
1.0
Receiver Input Thresholds
vs Temperature
Supply Current vs Data Rate
4
LTC1382
TYPICAL PERFOR
M
A
N
CE CHARACTERISTICS
U
W
TEMPERATURE (C)
0
0
SUPPLY CURRENT (mA)
2
6
8
10
40
18
LTC1382 TPC04
4
20
10
50
30
60
70
12
14
16
2 DRIVERS LOADED
R
L
= 3k
1 DRIVER LOADED
R
L
= 3k
V
CC
Supply Current
vs Temperature
Receiver Short-Circuit Current
vs Temperature
TEMPERATURE (C)
0
10
SHORT-CIRCUIT CURRENT (mA)
30
20
40
LTC1382 TPC06
20
10
I
SC
+
I
SC
50
30
60
70
40
50
Driver Short-Circuit Current
vs Temperature
TEMPERATURE (C)
0
0
SHORT-CIRCUIT CURRENT (mA)
2
6
8
10
40
18
LTC1382 TPC05
4
20
10
50
30
60
70
12
14
16
I
SC
I
SC
+
Driver Leakage in Shutdown
vs Temperature
TEMPERATURE (C)
0
LEAKAGE CURRENT (
A)
60
45
40
35
30
25
20
15
10
5
0
LTC1349 TPC05
20
70
10
30
40
50
V
OUT
= 20V
V
OUT
= 20V
Driver Output Waveforms
Receiver Output Waveforms
INPUT
INPUT
LTC1382 TPC08
LTC1382 TPC09
RECEIVER
OUTPUT
C
L
= 51pF
DRIVER
OUTPUT
R
L
= 3k
C
L
= 2500pF
DRIVER
OUTPUT
R
L
= 3k
5
LTC1382
PI FU CTIO S
U
U
U
V
CC
: 5V Input Supply Pin. This pin should be decoupled
with a 0.1
F ceramic capacitor.
GND: Ground Pin.
ON/OFF: TTL/CMOS Compatible Shutdown Pin. A logic
low puts the device in the Shutdown mode. Both driver
outputs are forced into three-state and the supply current
is 0.2
A.
V
+
: Positive Supply Output (RS232 Drivers). V
+
2V
CC
2V. This pin requires an external capacitor C = 0.1
F for
charge storage. The capacitor may be tied to ground or
V
CC
. With multiple devices, the V
+
and V
pins may share
a common capacitor. For large numbers of devices, in-
creasing the size of the shared common storage capaci-
tors is recommended to reduce ripple.
V
: Negative Supply Output (RS232 Drivers). V
(2V
CC
2V). This pin requires an external capacitor C = 0.1
F for
charge storage.
C1
+
, C1
, C2
+
, C2
: Commutating Capacitor Inputs. These
pins require two external capacitors C = 0.1
F: one from
C1
+
to C1
and another from C2
+
to C2
. To maintain
charge pump efficiency, the capacitor's effective series
resistance should be less than 2
.
TR IN: RS232 Driver Input Pins. Inputs are TTL/CMOS
compatible. The inputs of unused drivers can be left
unconnected since 300k input pull-up resistors to V
CC
are
included on chip. To minimize power consumption, the
internal driver pull-up resistors are disconnected from V
CC
in the Shutdown mode.
TR OUT: Driver Outputs at RS232 Voltage Levels. Outputs
are in a high impedance state when in the Shutdown or
V
CC
= 0V. The driver outputs are protected against ESD to
10kV for human body model discharges.
RX IN: Receiver Inputs. These pins can be forced to
25V
without damage. The receiver inputs are protected against
ESD to
10kV for human body model discharges. Each
receiver provides 0.4V of hysteresis for noise immunity.
RX OUT: Receiver Outputs with TTL/CMOS Voltage Lev-
els. Outputs are in a high impedance state when in the
Shutdown mode.
Figure 1. Driver Propagation Delay Timing
Figure 2. Receiver Propagation Delay Timing
SWITCHI G TI E WAVEFOR S
W
W
U
1.4V
0V
V
CC
0V
V
+
V
0V
DRIVER
INPUT
DRIVER
OUTPUT
1.4V
t
HLD
t
LHD
LTC1382 F01
0.8V
V
CC
0V
2.4V
RX
INPUT
RX
OUTPUT
1.3V
t
HLR
1.7V
t
LHR
LTC1382 F02
V
CC
0V
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