1
LTC1349
1349fa
5V Low Power RS232
3-Driver/5-Receiver Transceiver
with 2 Receivers Active
in Shutdown
Quiescent and Shutdown Supply Current
vs Temperature
■
Low Supply Current: 300µA
■
Two Receivers Kept Alive in Shutdown
■
ESD Protection Over ±10kV
■
Operates from a Single 5V Supply
■
Uses Small Capacitors: 0.1µF
■
Operates to 120k Baud
■
Three-State Outputs Are High Impedance When Off
■
Output Overvoltage Does Not Force Current
Back into Supplies
■
RS232 I/O Lines Can Be Forced to ±25V
Without Damage
■
Pin Compatible with LT1137A and LT1237
■
Flowthrough Architecture
The LTC
®
1349 is a 3-driver/5-receiver RS232 transceiver
with very low supply current. In the no load condition, the
supply current is only 300µA. The charge pump only
requires four 0.1µF capacitors.
In Shutdown mode, two receivers are kept alive and the
supply current is 35µA. All RS232 outputs assume a high
impedance state in Shutdown and with the power off.
The LTC1349 is fully compliant with all data rate and
overvoltage RS232 specifications. The transceiver can
operate up to 120k baud with a 2500pF, 3kΩ load. Both
driver outputs and receiver inputs can be forced to ±25V
without damage, and can survive multiple ±10kV ESD
strikes.
■
Notebook Computers
■
Palmtop Computers
TEMPERATURE (°C)
QUIESCENT CURRENT (µA)
1200
1000
800
600
400
200
020 40 60
LTC1349 • TA02
800
–40
60
50
40
30
20
10
0
SHUTDOWN CURRENT (µA)
QUIESCENT
CURRENT
SHUTDOWN
CURRENT
TEST CONDITION:
VCC = 5V, ALL DRIVER INPUTS TIED TO VCC.
–20 100
3-Drivers/5-Receivers with Shutdown
LTC1349 • TA01
V
CC
C1
0.1µF
LTC1349
1
2
3
4
5
6
7
8
9
10
11
12
13
14
DRIVER 1 OUT
RX1 IN
DRIVER 2 OUT
RX2 IN
RX3 IN
RX4 IN
DRIVER 3 OUT
RX5 IN
ON/OFF
NC
28
27
26
25
24
23
22
21
20
19
18
17
16
15
C3
0.1µF
DRIVER 1 IN
RX1 OUT
DRIVER 2 IN
RX2 OUT
RX3 OUT
RX4 OUT
DRIVER 3 IN
RX5 OUT
GND
NC
NC
V
–
V
+
C2
0.1µF
C4
0.1µF
FEATURES
DESCRIPTIO
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APPLICATIO S
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TYPICAL APPLICATIO
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, LTC and LT are registered trademarks of Linear Technology Corporation.
2
LTC1349
1349fa
LTC1349CG
LTC1349CNW
LTC1349CSW
LTC1349IG
LTC1349INW
LTC1349ISW
ORDER PART
NUMBER
Supply Voltage (V
CC
)................................................ 6V
Input Voltage
Driver ....................................... –0.3V to V
CC
+ 0.3V
Receiver ............................................... – 25V to 25V
On/Off Pin.................................. – 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
Commercial (LTC1349C) ........................ 0°C to 70°C
Industrial (LTC1349I) ........................ – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
V+
VCC
C1+
C1–
DR1 OUT
RX1 IN
DR2 OUT
RX2 IN
RX3 IN
RX4 IN
DR3 OUT
RX5 IN
ON/OFF
NC
V–
C2+
C2–
DR1 IN
RX1 OUT
DR2 IN
RX2 OUT
RX3 OUT
RX4 OUT
DR3 IN
RX5 OUT
GND
NC
NC
NW PACKAGE
28-LEAD PDIP
TOP VIEW
SW PACKAGE
28-LEAD PLASTIC SO
G PACKAGE
28-LEAD SSOP
T
JMAX
= 125°C, θ
JA
= 96°C/W (G)
T
JMAX
= 125°C, θ
JA
= 56°C/W (NW)
T
JMAX
= 125°C, θ
JA
= 85°C/W (SW)
Consult LTC Marketing for parts specified with wider operating temperature
ranges.
The ● denotes specifications which apply over the full operating
temperature range. VCC = 5V, C1 = C2 = C3 = C4 = 0.1µF, unless noted.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Any Driver
Output Voltage Swing 3k to GND Positive ● 5.0 7.0 V
Negative ●–5.0 – 6.5 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
Logic Input Current V
IN
= 5V ● 5 µA
V
IN
= 0V ●–5 µA
Output Short-Circuit Current V
OUT
= 0V ±9±12 mA
Output Leakage Current Shutdown, V
OUT
= ±20V (Note 3) ●±10 ±500 µA
Any Receiver
Input Voltage Thresholds Input Low Threshold ●0.8 1.3 V
Input High Threshold ●1.7 2.4 V
Hysteresis ●0.1 0.4 1.0 V
Input Resistance –10V ≤ V
IN
≤ 10V 3 5 7 kΩ
Output Voltage Output Low, I
OUT
= – 1.6mA (V
CC
= 5V) ●0.2 0.4 V
Output High, I
OUT
= 160µA (V
CC
= 5V) ●3.5 4.8 V
Output Short-Circuit Current Sinking Current, V
OUT
= V
CC
–15 –40 mA
Output Leakage Current Shutdown, 0 ≤ V
OUT
≤ V
CC
(Note 3) ●110 µA
Power Supply Generator
V
+
Output Voltage I
OUT
= 0mA 8.0 V
I
OUT
= 12mA 7.5 V
V
–
Output Voltage I
OUT
= 0mA –8.0 V
I
OUT
= –12mA –7.0 V
Supply Rise Time Shutdown to Turn-On 0.2 ms
ABSOLUTE AXI U RATI GS
WWWU
PACKAGE/ORDER I FOR ATIO
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DC ELECTRICAL CHARACTERISTICS
3
LTC1349
1349fa
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.
The ● denotes specifications which apply over the full operating
temperature range. VCC = 5V, C1 = C2 = C3 = C4 = 0.1µF, unless noted.
The ● denotes specifications which apply over the full operating temperature range.
VCC = 5V, C1 = C2 = C3 = C4 = 0.1µF, unless noted.
TYPICAL PERFOR A CE CHARACTERISTICS
UW
AC CHARACTERISTICS
DC ELECTRICAL CHARACTERISTICS
PARAMETER CONDITIONS MIN TYP MAX UNITS
Power Supply
V
CC
Supply Current No Load (All Drivers V
IN
= V
CC
)(Note 2), 0°C ≤ T
A
≤ 70°C●0.3 0.8 mA
No Load (All Drivers V
IN
= 0V)(Note 2), 0°C ≤ T
A
≤ 70°C●0.5 1.0 mA
No Load (All Drivers V
IN
= V
CC
)(Note 2), 0°C ≤ T
A
≤ 85°C●0.3 1.0 mA
No Load (All Drivers V
IN
= V
CC
)(Note 2), –40°C ≤ T
A
≤ 0°C●0.3 1.5 mA
No Load (All Drivers V
IN
= 0V)(Note 2), –40°C ≤ T
A
≤ 85°C●0.5 1.5 mA
Supply Leakage Current (V
CC
)Shutdown (Note 3) ●35 50 µA
On/Off Threshold Low ●1.4 0.8 V
On/Off Threshold High ●2.0 1.4 V
PARAMETER CONDITIONS MIN TYP MAX UNITS
Slew Rate R
L
= 3k, C
L
= 51pF 8 30 V/µs
R
L
= 3k, C
L
= 2500pF 3 5 V/µs
Driver Propagation Delay t
HLD
(Figure 1) ●23.5 µs
(TTL to RS232) t
LHD
(Figure 1) ●23.5 µs
Receiver Propagation Delay t
HLR
(Figure 2) ●0.3 0.8 µs
(RS232 to TTL) t
LHR
(Figure 2) ●0.2 0.8 µs
Note 3: Supply current and leakage current measurements in Shutdown
are performed with V
ON/OFF
= 0V.
Driver Output Voltage Supply Current vs Data RateReceiver Input Thresholds
TEMPERATURE (°C)
–40
–8
DRIVER OUTPUT VOLTAGE (V)
–6
–2
0
2
40
10
LTC1349 • TPC01
–4
0 100
4
6
8
–20 20 60 80
R
L
= 3k OUTPUT HIGH
V
CC
= 5V
V
CC
= 4.5V
OUTPUT LOW
V
CC
= 4.5V
V
CC
= 5V
DATA RATE (k BAUD)
0
SUPPLY CURRENT (mA)
150
45
40
35
30
25
20
15
10
5
0
LTC1349 • TPC03
50 17525 75 100 125
V
CC
= 5V
R
L
= 3k
C
L
= 2500pF
3 DRIVERS ACTIVE
TEMPERATURE (˚C)
–40
THRESHOLD VOLTAGE (V)
1.8
2.0
2.2
20 60
LTC1349 • TPC02
1.6
1.4
–20 0 40 80 100
1.2
1.0
V
TH
V
TL
4
LTC1349
1349fa
TYPICAL PERFOR A CE CHARACTERISTICS
UW
UU
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PI FU CTIO S
With multiple devices, the V
+
and V
–
pins may be paral-
leled into common capacitors. For large numbers of de-
vices, increasing the size of the shared common storage
capacitors is recommended to reduce ripple.
V
–
: Negative Supply Output (RS232 Drivers). V
–
≅ 2V
CC
–
1.5V. This pin requires an external capacitor C = 0.1µF for
charge storage.
C1
+
, C1
–
, C2
+
, C2
–
: Commutating Capacitor Inputs. These
pins require two external capacitors C = 0.1µF: 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 20Ω.
DRIVER
OUTPUT
R
L
= 3k
DRIVER
OUTPUT
R
L
= 3k
C
L
= 2500pF
INPUT
RECEIVER
OUTPUT
C
L
= 2500pF
INPUT
LTC1349 • TPC08 LTC1349 • TPC09
VCC Supply Current Driver Short-Circuit Current
Driver Leakage in Shutdown
TEMPERATURE (°C)
0
SUPPLY CURRENT (mA)
60
20
16
14
12
10
8
6
4
2
0
LTC1349 • TPC04
20 7010 30 40 50
3 DRIVERS LOADED
RL = 3k
1 DRIVER LOADED
RL = 3k
TEMPERATURE (°C)
0
LEAKAGE CURRENT (µA)
60
45
40
35
30
25
20
15
10
5
0
LTC1349 • TPC05
20 7010 30 40 50
V
OUT
= –20V
V
OUT
= 20V
TEMPERATURE (°C)
–40
0
SHORT-CIRCUIT CURRENT (mA)
4
8
10
12
40
20
LTC1349 • TPC06
6
080
14
16
18
–20 60
20 100
I
SC+
I
SC–
Receiver Short-Circuit Current Receiver Output WaveformsDriver Output Waveforms
TEMPERATURE (°C)
–40
10
SHORT-CIRCUIT CURRENT (mA)
30
60
040 60
LTC1349 • TPC07
20
50
40
–20 20 80 100
I
SC–
I
SC+
V
CC
: 5V Input Supply Pin. Supply current is typically 35µA
in the Shutdown mode. This pin should be decoupled with
a 0.1µF ceramic capacitor.
GND: Ground Pin.
ON/OFF: TTL/CMOS Compatible Shutdown Pin. A logic
low puts the device in Shutdown mode, with receivers 4
and 5 kept alive and the supply current equal to 35µA. All
driver outputs and other receiver outputs are in high
impedance state. This pin can not float.
V
+
: Positive Supply Output (RS232 Drivers). V
+
≅ 2V
CC
–
1V. This pin requires an external capacitor C = 0.1µF for
charge storage. The capacitor may be tied to ground or 5V.
5
LTC1349
1349fa
UU
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PI FU CTIO S
DRIVER IN: RS232 Driver Input Pins. Inputs are TTL/
CMOS compatible. Inputs should not be allowed to float.
Tie unused inputs to V
CC
.
DRIVER OUT: Driver Outputs at RS232 Voltage Levels.
Outputs are in a high impedance state when in Shutdown
mode 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. Receiver 1, 2 and 3 outputs are in a high impedance
state when in Shutdown mode to allow data line sharing.
Receivers 4 and 5 are kept alive in Shutdown.
SWITCHI G TI E WAVEFOR S
UWW
Figure 1. Driver Propagation Delay Timing
Figure 2. Receiver Propagation Delay Timing
1.4V
0V
VCC
0V
V+
V–
0V
DRIVER
INPUT
DRIVER
OUTPUT
1.4V
tHLD
tLHD
LTC1349 • F01
0.8V
VCC
0V
2.4V
RX
INPUT
RX
OUTPUT
1.3V
tHLR
1.7V
tLHR
LTC1349 • F02
VCC
0V
TEST CIRCUITS
Driver Timing Test Load Receiver Timing Test Load
DRIVER
DRIVER
INPUT
3k
51pF
DRIVER
OUTPUT
LTC1349 • TA03
RX
RX INPUT
51pF
RX
OUTPUT
LTC1349 • TA04
6
LTC1349
1349fa
TEST CIRCUITS
ESD Test Circuit
LTC1349 • TC
V
CC
C1
0.1µF
LTC1349
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
C3
0.1µF
V
–
V
+
C2
0.1µF
C4
0.1µF
RS232
LINE PINS
PROTECTED
TO ±10kV
DRIVER 1 IN
RX1 OUT
DRIVER 2 IN
RX2 OUT
RX3 OUT
RX4 OUT
DRIVER 3 IN
RX5 OUT
GND
NC
NC
DRIVER 1 OUT
RX1 IN
DRIVER 2 OUT
RX2 IN
RX3 IN
RX4 IN
DRIVER 3 OUT
RX5 IN
ON/OFF
NC
7
LTC1349
1349fa
U
PACKAGE DESCRIPTIO
NW28 1002
.505 – .560*
(12.827 – 14.224)
1.467*
(36.957)
MAX
12345678910
27 19
20212224 23
252628
11 12 13 14
15
16
1718
.008 – .015
(0.203 – 0.381)
.625 +.035
–.015
+0.889
–0.381
15.87
()
.600 – .625
(15.240 – 15.875)
.070
(1.778)
TYP
.015
(0.381)
MIN
.120
(3.175)
MIN
.150 ± .005
(3.810 ± 0.127)
.018 ± .003
(0.457 ± 0.076)
.035 – .080
(0.889 – 2.032)
.045 – .065
(1.143 – 1.651)
NOTE:
1. DIMENSIONS ARE INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
.100
(2.54)
BSC
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
G28 SSOP 0802
0.09 – 0.25
(.0035 – .010)
0° – 8°
0.55 – 0.95
(.022 – .037)
5.00 – 5.60**
(.197 – .221)
7.40 – 8.20
(.291 – .323)
1234567891011 12 1413
9.90 – 10.50*
(.390 – .413)
2526 22 21 20 19 18 17 16 1523242728
2.0
(.079)
0.05
(.002)
0.65
(.0256)
BSC 0.22 – 0.38
(.009 – .015)
MILLIMETERS
(INCHES)
DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED .152mm (.006") PER SIDE
DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED .254mm (.010") PER SIDE
*
**
NOTE:
1. CONTROLLING DIMENSION: MILLIMETERS
2. DIMENSIONS ARE IN
3. DRAWING NOT TO SCALE
0.42 ±0.03 0.65 BSC
5.3 – 5.7
7.8 – 8.2
RECOMMENDED SOLDER PAD LAYOUT
1.25 ±0.12
G Package
28-Lead Plastic SSOP (5.3mm)
(Reference LTC DWG # 05-08-1640)
NW Package
28-Lead PDIP (Wide .600 Inch)
(Reference LTC DWG # 05-08-1520)
8
LTC1349
1349fa
LINEAR TECHN OLOGY CORPORATION 1993
LW/TP 1102 1K REV A • PRINTED IN USA
S28 (WIDE) 0502
0° – 8° TYP
NOTE 3
.009 – .013
(0.229 – 0.330)
.016 – .050
(0.406 – 1.270)
.291 – .299
(7.391 – 7.595)
NOTE 4
× 45°
.010 – .029
(0.254 – 0.737)
.037 – .045
(0.940 – 1.143)
.004 – .012
(0.102 – 0.305)
.093 – .104
(2.362 – 2.642)
.050
(1.270)
BSC .014 – .019
(0.356 – 0.482)
TYP
NOTE 3
.697 – .712
(17.70 – 18.08)
NOTE 4
12345678
.394 – .419
(10.007 – 10.643)
910
2526
11 12
22 21 20 19 18 17 16 152324
14
N/2
13
2728
N
.420
MIN
.325 ±.005
RECOMMENDED SOLDER PAD LAYOUT
.045 ±.005
N
123 N/2
.050 BSC
.030 ±.005
TYP
.005
(0.127)
RAD MIN
INCHES
(MILLIMETERS)
NOTE:
1. DIMENSIONS IN
2. DRAWING NOT TO SCALE
3. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS.
THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS
4. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7487
(408) 432-1900
●
FAX
: (408) 434-0507
●
WWW
.linear.com
U
PACKAGE DESCRIPTIO
RELATED PARTS
PART NUMBER DESCRIPTION COMMENTS
LT®1137A 5V, 3 Driver, 5 Receiver RS232 Transceiver ±15kV ESD per IEC 1000-4
LTC1327 3.3V, 3 Driver, 5 Receiver RS562 Transceiver 300µA Supply Current, 0.2µA in Shutdown
LTC1337 5V, 3 Driver, 5 Receiver RS232 Transceiver 300µA Supply Current, 1µA in Shutdown
LTC1348 3.3V to 5V, 3 Driver, 5 Receiver RS232 Transceiver True RS232 on 3.3V, 5 Receivers Active in Shutdown
SW Package
28-Lead Plastic Small Outline (Wide .300 Inch)
(Reference LTC DWG # 05-08-1620)
