1
LTC1383
5V Low Power
RS232 Transceiver
S
FEATURE
D
U
ESCRIPTIO
s
Operates from a Single 5V Supply
s
Low Supply Current: I
CC
= 220
A
s
ESD Protection Over
10kV
s
Available in 16-Pin SOIC Narrow Package
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 LT1181A and MAX232A
The LTC1383 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 supply current (I
CC
) of the
transceiver is only 220
A with driver outputs unloaded.
The LTC1383 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
LTC1383 TA01
LTC1383
1
3
0.1
F
16
V
CC
= 5V
2
0.1
F
6
0.1
F
0.1
F
4
5
232 OUTPUT
14
7
232 OUTPUT
13
232 INPUT
5k
8
232 INPUT
15
11
10
12
9
LOGIC INPUT
LOGIC INPUT
LOGIC OUTPUT
LOGIC OUTPUT
5k
300k
V
CC
300k
V
CC
Quiescent Supply Current vs Temperature
TEMPERATURE (C)
20
0
QUIESCENT CURRENT (
A)
100
200
300
400
600
0
20
40
60
LTC1383 TA02
80
500
TEST CONDITION: V
CC
= 5V
QUIESCENT
CURRENT
2
LTC1383
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
T
JMAX
= 125
C,
JA
= 65
C/W (N)
T
JMAX
= 125
C,
JA
= 95
C/W (S)
1
2
3
4
5
6
7
8
TOP VIEW
S PACKAGE
16-LEAD NARROW
PLASTIC SOIC
16
15
14
13
12
11
10
9
C1
+
V
+
C1
C2
+
C2
V
TR2 OUT
RX2 IN
V
CC
GND
TR1 OUT
RX1 IN
RX1 OUT
TR1 IN
TR2 IN
RX2 OUT
N PACKAGE
16-LEAD PLASTIC DIP
LTC1383CN
LTC1383CS
Consult factory for Industrial and Military grade products.
ELECTRICAL C
C
HARA TERISTICS
C
D
V
CC
= 5V, C1 = C2 = C3 = C4 = 0.1
F, 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
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
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
3
LTC1383
ELECTRICAL C
C
HARA TERISTICS
C
D
C
C
HARA TERISTICS
AC
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.
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
Note 2: Supply current is measured with driver and receiver outputs
unloaded.
TYPICAL PERFOR
M
A
N
CE CHARACTERISTICS
U
W
TEMPERATURE (C)
0
8
DRIVER OUTPUT VOLTAGE (V)
6
2
0
2
40
10
LTC1383 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
Driver Output Voltage
vs Temperature
DATA RATE (kBAUD)
0
0
SUPPLY CURRENT (mA)
5
15
20
25
100
45
LTC1383 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
LTC1383 TPC02
1.6
1.4
10
20
40
60
70
1.2
1.0
Receiver Input Thresholds
vs Temperature
Supply Current vs Data Rate
V
CC
= 5V, C1 = C2 = C3 = C4 = 0.1
F, unless otherwise noted.
V
CC
= 5V, C1 = C2 = C3 = C4 = 0.1
F, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Power Supply
V
CC
Supply Current
No Load (Note 2)
q
0.22
0.5
mA
Digital Input Threshold Low
q
1.4
0.8
V
Digital Input Threshold High
q
2.0
1.4
V
4
LTC1383
TYPICAL PERFOR
M
A
N
CE CHARACTERISTICS
U
W
V
CC
Supply Current
vs Temperature
TEMPERATURE (C)
0
0
SUPPLY CURRENT (mA)
2
6
8
10
40
18
LTC1383 TPC04
4
20
10
50
30
60
70
12
14
16
2 DRIVERS LOADED
R
L
= 3k
1 DRIVER LOADED
R
L
= 3k
Driver Output Waveforms
Receiver Output Waveforms
INPUT
LTC1383 TPC05
RECEIVER
OUTPUT
C
L
= 51pF
INPUT
LTC1383 TPC06
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.
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.
TR OUT: Driver Outputs at RS232 Voltage Levels. 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
Levels.
DRIVER
OUTPUT
R
L
= 3k
C
L
= 2500pF
DRIVER
OUTPUT
R
L
= 3k
5
LTC1383
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
LTC1383 F01
Figure 1. Driver Propagation Delay Timing
0.8V
V
CC
0V
2.4V
RX
INPUT
RX
OUTPUT
1.3V
t
HLR
1.7V
t
LHR
LTC1383 F02
V
CC
0V
Figure 2. Receiver Propagation Delay Timing
Driver Timing Test Load
TEST CIRCUITS
Receiver Timing Test Load
DRIVER
DRIVER
INPUT
3k
51pF
DRIVER
OUTPUT
LTC1383 TA03
RX
RX INPUT
51pF
RX
OUTPUT
LTC1383 TA04
ESD Test Circuit
LTC1383 TA05
LTC1383
1
3
0.1
F
16
V
CC
2
0.1
F
6
0.1
F
0.1
F
4
5
232 OUTPUT
14
7
232 OUTPUT
RS232
LINE PINS
PROTECTED
TO 10kV
13
232 INPUT
5k
8
232 INPUT
15
11
10
12
9
LOGIC INPUT
LOGIC INPUT
LOGIC OUTPUT
LOGIC OUTPUT
5k
300k
V
CC
300k
V
CC
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