1
LTC1338
5V Low Power RS232
5-Driver/3-Receiver Transceiver
S
FEATURE
D
U
ESCRIPTIO
■
Low Supply Current: 500µA
■
0.2µA Supply Current in SHUTDOWN
■
50µA Supply Current in RECEIVER ALIVE Mode
■
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
■
Flowthrough Architecture
The LTC1338 is a 5-driver/3-receiver RS232 trans-
ceiver with very low supply current. In the no load
condition, the supply current is only 500µA. The charge
pump only requires four 0.1µF capacitors.
In SHUTDOWN mode, the supply current is further
reduced to 0.2µA. In RECEIVER ALIVE mode, all three
receivers are kept alive and the supply current is 50µA.
All RS232 outputs assume a high impedance state in
SHUTDOWN and with the power off.
The LTC1338 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.
U
S
A
O
PPLICATI
■
Battery-Powered Modems
■
Battery-Powered DCE
■
Notebook Computers
■
Palmtop Computers
U
A
O
PPLICATITYPICAL
5-Drivers/3-Receivers with SHUTDOWN
LTC1338 • TA01
V
CC
C1
0.1µF
LTC1338
1
2
3
4
5
6
7
8
9
10
11
12
13
14
DRIVER 1 OUT
DRIVER 2 OUT
RX1 IN
DRIVER 3 OUT
RX2 IN
DRIVER 4 OUT
RX3 IN 
DRIVER 5 OUT
RX ENABLE
NC
28
27
26
25
24
23
22
21
20
19
18
17
16
15
C3
0.1µF
DRIVER 1 IN
DRIVER 2 IN
RX1 OUT
DRIVER 3 IN
RX2 OUT
DRIVER 4 IN
RX3 OUT
DRIVER 5 IN
GND
DRIVER ENABLE
NC
V
–
V
+
C2
0.1µF
C4
0.1µF
TEMPERATURE (°C)
QUIESCENT CURRENT (µA)
1200
1000
800
600
400
200
020 40 60
LTC1338 • TA02
800
–20
1.2
1.0
0.8
0.6
0.4
0.2
0
SHUTDOWN CURRENT (µA)
QUIESCENT
CURRENT
SHUTDOWN
CURRENT
–40
TEST CONDITION:
V
CC
= 5V, ALL DRIVER INPUTS TIED TO V
CC
.
100
Supply Current
2
LTC1338
A
U
G
W
A
W
U
W
ARBSOLUTEXI T
I
S
WU
U
PACKAGE/ORDER I FOR ATIO
ORDER PART
NUMBER
1
2
3
4
5
6
7
8
9
10
11
12
13
14
V
+
V
CC
C1
+
C1
–
DR1 OUT
DR2 OUT
RX1 IN
DR3 OUT
RX2 IN
DR4 OUT
RX3 IN
DR5 OUT
RX ENABLE
NC
28
27
26
25
24
23
22
21
20
19
18
17
16
15
V
–
C2
+
C2
–
DR1 IN
DR2 IN
RX1 OUT
DR3 IN
RX2 OUT
DR4 IN
RX3 OUT
DR5 IN
GND
DR ENABLE
NC
N PACKAGE
28-LEAD PLASTIC DIP
TOP VIEW
S PACKAGE
28-LEAD PLASTIC SOL
G PACKAGE
28-LEAD SSOP
T
JMAX
= 125°C, θ
JA
= 96°C/W (G)
T
JMAX
= 125°C, θ
JA
= 56°C/W (N)
T
JMAX
= 125°C, θ
JA
= 85°C/W (S)
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 0 ≤ V
IN
≤ V
CC
● ±5µA
Output Short-Circuit Current V
OUT
= 0V ±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 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
LTC1338CG
LTC1338CN
LTC1338CS
LTC1338IG
LTC1338IN
LTC1338IS
Supply Voltage (V
CC
) ................................................ 6V
Input Voltage
Driver ....................................... –0.3V to V
CC
+ 0.3V
Receiver ............................................... – 25V to 25V
Driver/Receiver Enable 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 (LTC1338C) ........................ 0°C to 70°C
Industrial (LTC1338I) ........................ –40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
(Note 1)
VCC = 5V, C1 = C2 = C3 = C4 = 0.1µF, unless otherwise noted.
ELECTRICAL C CHARA TERISTICSCD
3
LTC1338
VCC = 5V, C1 = C2 = C3 = C4 = 0.1µF, unless otherwise noted.
ELECTRICAL C CHARA TERISTICSCD
CCHARA TERISTICS
AC
Note 3: Supply current and leakage current measurements in SHUTDOWN
are performed with V
DRIVER ENABLE
and V
RECEIVER ENABLE
= 0V.
Note 4: Supply current measurement in RECEIVER ALIVE mode is
performed with V
DRIVER ENABLE
= 0V and V
RECEIVER ENABLE
= V
CC
.
The ● denotes specifications which apply over the operating temperature
range of 0°C to 70°C or –40°C to 85°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. The V
DRIVER ENABLE
and V
RECEIVER ENABLE
= V
CC
.
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) ●2 3.5 µs
(TTL to RS232) t
LHD
(Figure 1) ●2 3.5 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
VCC = 5V, C1 = C2 = C3 = C4 = 0.1µF, unless otherwise noted.
TYPICAL PERFOR A CE CHARACTERISTICS
WU
DATA RATE (k BAUD)
0
SUPPLY CURRENT (mA)
40
50
60
60 100
LTC1338 • TPC03
30
20
20 40 80 120 140
10
0
V
CC
= 5V
R
L
= 3k
C
L
= 2500pF
5 DRIVERS ACTIVE
TEMPERATURE (˚C)
–40
THRESHOLD VOLTAGE (V)
1.8
2.0
2.2
20 60
LTC1338 • TPC02
1.6
1.4
–20 0 40 80 100
1.2
1.0
V
TH
V
TL
TEMPERATURE (°C)
–40
–8
DRIVER OUTPUT VOLTAGE (V)
–6
–2
0
2
40
10
LTC1338 • TPC01
–4
080
4
6
8
–20 60
20 100
R
L
= 3k OUTPUT HIGH
V
CC
= 5V
V
CC
= 4.5V
OUTPUT LOW
V
CC
= 4.5V
V
CC
= 5V
Driver Output Voltage Receiver Input Thresholds Supply Current vs Data Rate
PARAMETER CONDITIONS MIN TYP MAX UNITS
Power Supply
V
CC
Supply Current No Load (All Driver V
IN
= V
CC
)(Note 2) 0°C ≤ T
A
≤ 70°C 0.5 1.0 mA
No Load (All Driver V
IN
= 0V)(Note 2) 0°C ≤ T
A
≤ 70°C 1.0 1.5 mA
No Load (All Driver V
IN
= V
CC
)(Note 2) –40°C ≤ T
A
≤ 85°C 0.5 1.5 mA
No Load (All Driver V
IN
= 0V)(Note 2) –40°C ≤ T
A
≤ 85°C 1.0 2.0 mA
RECEIVER ALIVE Mode (Note 4) ●50 80 µA
Supply Leakage Current (V
CC
) SHUTDOWN (Note 3) ●0.2 10 µA
Driver/Receiver Enable Threshold Low ●1.4 0.8 V
Driver/Receiver Enable Threshold High ●2.0 1.4 V
4
LTC1338
TYPICAL PERFOR A CE CHARACTERISTICS
WU
V
CC Supply Current Driver Leakage in Shutdown Driver Short-Circuit Current
TEMPERATURE (°C)
–40
SUPPLY CURRENT (mA)
20
25
30
20 60
LTC1338 • TPC04
15
10
–20 0 40 80 100
5
0
5 DRIVERS LOADED
R
L
= 3k
1 DRIVER LOADED
R
L
= 3k
TEMPERATURE (°C)
–40
0
SHORT-CIRCUIT CURRENT (mA)
4
8
10
12
40
20
LTC1338 • TPC06
6
080
14
16
18
–20 60
20 100
I
SC+
I
SC–
TEMPERATURE (°C)
–40
0
LEAKAGE CURRENT (µA)
20
50
040 60
LTC1338 • TPC05
10
40
30
–20 20 80 100
V
OUT
= –20V
V
OUT
= 20V
Receiver Short-Circuit Current Driver Output Waveforms Receiver Output Waveforms
TEMPERATURE (°C)
–40
10
SHORT-CIRCUIT CURRENT (mA)
30
60
040 60
LTC1338 • TPC07
20
50
40
–20 20 80 100
I
SC–
I
SC+
DRIVER
OUTPUT
R
L
= 3k
C
L
= 2500pF
DRIVER
OUTPUT
R
L
= 3k
INPUT
LTC1338 • TPC08 LTC1338 • TPC09
RECEIVER
OUTPUT
C
L
= 50pF
INPUT
PI FU CTIO S
U
UU
V
CC
: 5V Input Supply Pin. Supply current less than 0.2µA
in the SHUTDOWN mode. This pin should be decoupled
with a 0.1µF ceramic capacitor.
GND: Ground Pin.
RECEIVER ENABLE: TTL/CMOS Compatible Enable Pin.
Refer to Table 1 for its functional description. This pin can
not float.
DRIVER ENABLE: TTL/CMOS Compatible Enable Pin. Re-
fer to Table 1 for its functional description. 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.
With multiple devices, the V
+
and V
–
pins may be paral-
leled into common capacitors. For large numbers of
devices, 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.
5
LTC1338
PI FU CTIO S
U
UU
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 SHUT-
DOWN, RECEIVER ALIVE 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. Outputs are in a high impedance state when in SHUT-
DOWN or RECEIVER DISABLE mode to allow data line
sharing.
Table 1. Functional Description
MODE RX ENABLE DR ENABLE DRIVERS RECEIVERS I
CC
(µA)(TYP)
SHUTDOWN 0 0 All driver outputs are All receiver outputs are 0.2
high impedance. high impedance.
Receiver Disable 0 1 All drivers alive. All receiver outputs are 500
high impedance.
RECEIVER ALIVE 1 0 All driver outputs are All receivers alive. 50
high impedance.
Normal 1 1 All drivers alive. All receivers alive. 500
TI
W
EWAVEFORS
U
G
WITCHI
W
S
Figure 1. Driver Propagation Delay Timing Figure 2. Receiver Propagation Delay Timing
1.4V
0V
V
CC
0V
V
+
V
–
0V
DRIVER
INPUT
DRIVER
OUTPUT
1.4V
t
HLD
t
LHD
LTC1338 • F01
0.8V
V
CC
0V
2.4V
RX
INPUT
RX
OUTPUT
1.3V
t
HLR
1.7V
t
LHR
LTC1338 • F02
V
CC
0V
6
LTC1338
TEST CIRCUITS
Driver Timing Test Load Receiver Timing Test Load
RX
RX INPUT
51pF
RX
OUTPUT
LTC1338 • F04
DRIVER
DRIVER
INPUT
3k
51pF
DRIVER
OUTPUT
LTC1338 • F03
ESD Test Circuit
LTC1338 • TC01
VCC
C1
0.1µF
LTC1338
1
2
3
4
5
6
7
8
9
10
11
12
13
14
DRIVER 1 OUT
DRIVER 2 OUT
RX1 IN
DRIVER 3 OUT
RX2 IN
DRIVER 4 OUT
RX3 IN
DRIVER 5 OUT
RX ENABLE
NC
28
27
26
25
24
23
22
21
20
19
18
17
16
15
C3
0.1µF
DRIVER 1 IN
DRIVER 2 IN
RX1 OUT
DRIVER 3 IN
RX2 OUT
DRIVER 4 IN
RX3 OUT
DRIVER 5 IN
GND
DRIVER ENABLE
NC
V–
V+
C2
0.1µF
C4
0.1µF
RS232
LINE PINS
PROTECTED
TO ±10kV
7
LTC1338
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.
0° – 8° TYP
NOTE 1
0.009 – 0.013
(0.229 – 0.330)
0.016 – 0.050
(0.406 – 1.270)
0.291 – 0.299
(7.391 – 7.595)
(NOTE 2)
× 45°
0.010 – 0.029
(0.254 – 0.737)
0.005
(0.127)
RAD MIN
0.037 – 0.045
(0.940 – 1.143)
0.004 – 0.012
(0.102 – 0.305)
0.093 – 0.104
(2.362 – 2.642)
0.050
(1.270)
TYP
0.014 – 0.019
(0.356 – 0.482)
NOTE 1
0.697 – 0.712
(17.70 – 18.08)
(NOTE 2)
0.394 – 0.419
(10.007 – 10.643)
123456789101112 1413
2526 22 21 20 19 18 17 16 1523242728
NOTE:
1. 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.
2. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm).
S Package
28-Lead SOL
PACKAGE DESCRIPTIO
U
Dimensions in inches (millimeters) unless otherwise noted.
G Package
28-Lead SSOP
0.301 – 0.311
(7.65 – 7.90)
12345678 9 10 11 12 1413
0.397 – 0.407*
(10.07 – 10.33)
2526 22 21 20 19 18 17 16 1523242728
0.045
(1.14)
0.045
(1.14)
0.068 – 0.078
(1.73 – 1.99)
0.002 – 0.008
(0.05 – 0.21)
0.0256
(0.65)
BSC
0.010 – 0.015
(0.25 – 0.38)
0.005 – 0.009
(0.13 – 0.22)
0° – 8°
0.022 – 0.037
(0.55 – 0.95)
0.205 – 0.212*
(5.20 – 5.38)
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm).
N Package
28-Lead Plastic DIP
0.505 – 0.560
(12.827 – 14.224)
1.455
(36.957)
MAX
123456789
10
27 19
20212224 23
252628
11 12 13 14
15
16
1718
0.009 – 0.015
(0.229 – 0.381)
0.625 +0.025
–0.015
+0.635
–0.381
15.87
()
0.600 – 0.625
(15.240 – 15.875)
0.070
(1.778)
TYP
0.015
(0.381)
MIN
0.125
(3.175)
MIN
0.130 ± 0.005
(3.302 ± 0.127)
0.018 ± 0.003
(0.457 ± 0.076)
0.035 – 0.080
(0.889 – 2.032)
0.100 ± 0.010
(2.540 ± 0.254)
0.045 – 0.065
(1.143 – 1.651)
8
LTC1338
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7487
(408) 432-1900
●
FAX
: (408) 434-0507
●
TELEX
: 499-3977
LINEAR TECHNOLOGY CORPORATION 1993
LT/GP 1093 10K REV 0 • PRINTED IN USA
NORTHEAST REGION
Linear Technology Corporation
One Oxford Valley
2300 E. Lincoln Hwy.,Suite 306
Langhorne, PA 19047
Phone: (215) 757-8578
FAX: (215) 757-5631
Linear Technology Corporation
266 Lowell St., Suite B-8
Wilmington, MA 01887
Phone: (508) 658-3881
FAX: (508) 658-2701
U.S. Area Sales Offices
SOUTHEAST REGION
Linear Technology Corporation
17060 Dallas Parkway
Suite 208
Dallas, TX 75248
Phone: (214) 733-3071
FAX: (214) 380-5138
CENTRAL REGION
Linear Technology Corporation
Chesapeake Square
229 Mitchell Court, Suite A-25
Addison, IL 60101
Phone: (708) 620-6910
FAX: (708) 620-6977
SOUTHWEST REGION
Linear Technology Corporation
22141 Ventura Blvd.
Suite 206
Woodland Hills, CA 91364
Phone: (818) 703-0835
FAX: (818) 703-0517
NORTHWEST REGION
Linear Technology Corporation
782 Sycamore Dr.
Milpitas, CA 95035
Phone: (408) 428-2050
FAX: (408) 432-6331
FRANCE
Linear Technology S.A.R.L.
Immeuble "Le Quartz"
58 Chemin de la Justice
92290 Chatenay Malabry
France
Phone: 33-1-41079555
FAX: 33-1-46314613
GERMANY
Linear Techonolgy GMBH
Untere Hauptstr. 9
D-85386 Eching
Germany
Phone: 49-89-3197410
FAX: 49-89-3194821
JAPAN
Linear Technology KK
5F YZ Bldg.
4-4-12 Iidabashi, Chiyoda-Ku
Tokyo, 102 Japan
Phone: 81-3-3237-7891
FAX: 81-3-3237-8010
TAIWAN
Linear Technology Corporation
Rm. 801, No. 46, Sec. 2
Chung Shan N. Rd.
Taipei, Taiwan, R.O.C.
Phone: 886-2-521-7575
FAX: 886-2-562-2285
UNITED KINGDOM
Linear Technology (UK) Ltd.
The Coliseum, Riverside Way
Camberley, Surrey GU15 3YL
United Kingdom
Phone: 44-276-677676
FAX: 44-276-64851
KOREA
Linear Technology Korea Branch
Namsong Building, #505
Itaewon-Dong 260-199
Yongsan-Ku, Seoul
Korea
Phone: 82-2-792-1617
FAX: 82-2-792-1619
SINGAPORE
Linear Technology Pte. Ltd.
101 Boon Keng Road
#02-15 Kallang Ind. Estates
Singapore 1233
Phone: 65-293-5322
FAX: 65-292-0398
World Headquarters
Linear Technology Corporation
1630 McCarthy Blvd.
Milpitas, CA 95035-7487
Phone: (408) 432-1900
FAX: (408) 434-0507
08/16/93
International Sales Offices