SHUTDOWN CURRENT (A)
LTC1348
3.3V/5V Low Power RS232
3-Driver/5-Receiver Transceiver
DESCRIPTIO
EATURES
F
n
Low Supply Current: 600A at 3.3V The LTC 1348 is a 3-driver/5-receiver RS232 transceiver
n
Supply Current in Shutdown: 0.2A with very low supply current. The charge pump only
n
Supply Current in Receiver Alive Mode: 15A requires five 0.1F capacitors. The LTC1348 provides full
n
ESD Protection over 10kV RS232 output levels when operated over a wide supply
n
Operates from a Single 3V to 5.5V Supply range of 3V to 5.5V
n
Operates to 120kBaud with 0.1F Flying Capacitors
The transceiver operates in one of four modes: Normal,
n
Three-State Outputs Are High Impedance When Off
Receiver Disable, Receiver Alive and Shutdown. In Normal
n
Output Overvoltage Does Not Force Current
or Receiver Disable mode, I is only 600A at 3.3V and
CC
Back into Supplies
800A at 5V in the no load condition. In Shutdown mode,
n
RS232 I/O Lines Can Be Forced to 25V
the supply current is further reduced to 0.2A. In Receiver
Without Damage
Alive mode, all five receivers are kept alive and the supply
n
Flowthrough Architecture
current is 15A. All RS232 outputs assume a high imped-
ance state in Shutdown or Receiver Alive mode or with the
power off. The receiver outputs assume a high impedance
APPLICATI S
state in Receiver Disable or with the power off.
n
Notebook Computers
The LTC1348 is fully compliant with all data rate and
n
Palmtop Computers
overvoltage RS232 specifications. The transceiver oper-
n
Printers
ates up to 120kbaud with all drivers loaded with 1000pF,
n
Portable Instruments
3k. Both driver outputs and receiver inputs can be forced
to 25V without damage and can survive multiple 10kV
ESD strikes.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATI
Supply Current
3-Drivers/5-Receivers with Shutdown
1.6 1.6
+
V
V 1
28
LTC1348
C5
C4
2
27
1.4 1.4
0.1F
0.1F
C2
C3
3
26
0.1F 0.1F 1.2 1.2
QUIESCENT
4
25
CURRENT
DR 1 IN
V
CC
1.0 1.0
5
24
RX1 OUT
V = 5V
C1
CC
6
23
0.8 0.8
0.1F
DR 2 IN
V = 3.3V
7
22
CC
DR 1 OUT
RX2 OUT
0.6 0.6
8
21
SHUTDOWN
RX1 IN
RX3 OUT
0.4 0.4
V = 3.3V
CURRENT
9
20
CC
DR 2 OUT
RX4 OUT
OR 5V
10
19
0.2 0.2
RX2 IN
DR 3 IN
11
18
RX3 IN
RX5 OUT
0 0
12
17
40 20 0 20 40 60 80
RX4 IN
DREN
13
16
TEMPERATURE (C)
DR 3 OUT
RXEN
LT1348 TA02
14 15
RX5 IN
GND
LT1348 TA01
1
SUPPLY CURRENT (mA)
UO
UO
ULTC1348
ABSOLUTEXAI U RATI GS PACKAGE/ORDER I FOR ATIO
(Note 1)
TOP VIEW
ORDER PART
Supply Voltage (V ) ................................................ 6V
CC
+ NUMBER
V
1
28
V
Input Voltage
+ +
C2
2
27
C3
Driver ....................................... 0.3V to V + 0.3V
CC
C2
3
26
C3
LTC1348CG
Receiver ............................................... 25V to 25V
V
4
25
DR1 IN
CC
LTC1348CSW
+
Driver/Receiver Enable Pin ........ 0.3V to V + 0.3V
C1
5
24
RX1 OUT
CC
LTC1348IG
Output Voltage C1
6
23
DR2 IN
LTC1348ISW
DR1 OUT
7
22
RX2 OUT
Driver ................................................... 25V to 25V
RX1 IN
8
21
RX3 OUT
Receiver .................................... 0.3V to V + 0.3V
CC
DR2 OUT
9
20
RX4 OUT
Short-Circuit Duration
RX2 IN
10
19
DR3 IN
+
V ................................................................... 30 sec RX3 IN
11
RX5 OUT
18
RX4 IN
12
17
DREN
V ................................................................... 30 sec
DR3 OUT
13
16
RXEN
Driver Output .............................................. Indefinite
RX5 IN
14 15 GND
Receiver Output .......................................... Indefinite
G PACKAGE
SW PACKAGE
Operating Temperature Range
28-LEAD PLASTIC SSOP 28-LEAD PLASTIC SO
LTC1348C................................................ 0C to 70C
T = 125C, = 96C/W (G)
JMAX JA
LTC1348I............................................ 40C to 85C T = 125C, = 85C/W (SW)
JMAX JA
Storage Temperature Range ................ 65C to 150C
Consult factory for Military grade parts.
Lead Temperature (Soldering, 10 sec)................. 300C
LECTR AL CHARACTERIST
DC E IC ICS
V = 3V to 5.5V, C1 to C4 = 0.1F, unless otherwise noted.
CC
PARAMETER CONDITIONS MIN TYP MAX UNITS
Any Driver
Output Voltage Swing V = 3.3V, 3k to GND Positive l 5.0 6.2 V
CC
Negative l 5.0 6.0 V
Logic Input Voltage Level Input Low Level (V = High) l 0.8 V
OUT
Input High Level (V = Low), V = 3.3V l 2.0 V
OUT CC
Input High Level (V = Low), V = 5V l 2.4 V
OUT CC
Logic Input Current V = V l 5 A
IN CC
V = 0V l 5 35 A
IN
Output Short-Circuit Current V = 0V 12 mA
OUT
Output Leakage Current Shutdown (Note 3) or Receiver Alive Mode (Note 4), l 10 500 A
V = 20V
OUT
Any Receiver
Input Voltage Thresholds Input Threshold (Receiver Alive Mode) 0.8 1.5 2.4 V
Input Low Threshold (Normal Mode) 0.8 1.3 V
Input High Threshold (Normal Mode) 1.7 2.4 V
Hysteresis Normal Mode 0.3 V
Input Resistance V = 10V 3 5 7 k
IN
Output Voltage Output Low, I = 1.6mA l 0.2 0.4 V
OUT
Output High, I = 160A l V 0.6V V
OUT CC
Output Short-Circuit Current Sinking Current, V = V 3 20 mA
OUT CC
Output Leakage Current Shutdown (Note 3), 0V V V l 110 A
OUT CC
2
U W W W
U WU