1347fa.pm7
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LTC1347
1347fa
5V Low Power RS232
3-Driver/5-Receiver Transceiver
with 5 Receivers Active
in Shutdown
Low Supply Current: 300A
Five Receivers Kept Alive in Shutdown
ESD Protection Over 10kV
Operates from a Single 5V Supply
Uses Small Capacitors: 0.1F
Operates to 120kBaud
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
1347 is a 3-driver/ 5-receiver RS232 transceiver
with very low supply current. In the no load condition, the
supply current is only 300A. The charge pump only
requires four 0.1F capacitors.
In Shutdown mode, all five receivers are kept alive and the
supply current is 80A. All RS232 outputs assume a high
impedance state in Shutdown and with the power off.
The LTC1347 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.
Notebook Computers
Palmtop Computers
3-Drivers/5-Receivers with Shutdown
Quiescent and Shutdown Supply Current
vs Temperature
1347 TA01
V
CC
C1
0.1F
LTC1347
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
0.1F
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
0.1F
C4
0.1F
TEMPERATURE (C)
QUIESCENT CURRENT (
A)
1200
1000
800
600
400
200
0
20
40
60
1347 TA02
80
0
40
120
100
80
60
40
20
0
SHUTDOWN CURRENT (
A)
QUIESCENT
CURRENT
SHUTDOWN
CURRENT
TEST CONDITION:
V
CC
= 5V, ALL DRIVER INPUTS TIED TO V
CC
.
20
100
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
LTC1347
1347fa
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 .................... 0C to 70C
Storage Temperature Range ................ 65C to 150C
Lead Temperature (Soldering, 10 sec)................. 300C
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
+
V
CC
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
ORDER PART
NUMBER
LTC1347CG
LTC1347CNW
LTC1347CSW
T
JMAX
= 125C,
JA
= 96C/W (G)
T
JMAX
= 125C,
JA
= 56C/W (NW)
T
JMAX
= 125C,
JA
= 85C/W (SW)
Consult LTC Marketing for parts specified with wider operating temperature
ranges.
DC ELECTRICAL CHARACTERISTICS
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
A
V
IN
= 0V
5
A
Output Short-Circuit Current
V
OUT
= 0V
9
12
mA
Output Leakage Current
Shutdown, V
OUT
= 20V (Note 3)
10
500
A
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
V
IN
= 10V
3
5
7
k
Output Voltage
Output Low, I
OUT
= 1.6mA (V
CC
= 5V)
0.2
0.4
V
Output High, I
OUT
= 160A (V
CC
= 5V)
3.5
4.8
V
Output Short-Circuit Current
Sinking Current, V
OUT
= V
CC
15
40
mA
Sourcing Current, V
OUT
= 0V
10
20
mA
The
denotes specifications which apply over the full operating
temperature range. V
CC
= 5V, C1 = C2 = C3 = C4 = 0.1F, unless otherwise noted.
ABSOLUTE AXI U RATI GS
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PACKAGE/ORDER I FOR ATIO
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LTC1347
1347fa
Note 3: Supply current and leakage current measurements in Shutdown
are performed with V
ON/OFF
= 0V.
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.
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)
2
3.5
s
(TTL to RS232)
t
LHD
(Figure 1)
2
3.5
s
Receiver Propagation Delay
t
HLR
(Figure 2)
0.3
0.8
s
(RS232 to TTL)
t
LHR
(Figure 2)
0.2
0.8
s
AC CHARACTERISTICS
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
Driver Output Voltage
TEMPERATURE (C)
40
8
DRIVER OUTPUT VOLTAGE (V)
6
2
0
2
40
10
1347 G01
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 (kBAUD)
0
SUPPLY CURRENT (mA)
150
45
40
35
30
25
20
15
10
5
0
1347 G03
50
175
25
75
100
125
V
CC
= 5V
R
L
= 3k
C
L
= 2500pF
3 DRIVERS ACTIVE
Supply Current vs Data Rate
TEMPERATURE (C)
40
THRESHOLD VOLTAGE (V)
1.8
2.0
2.2
20
60
1347 G02
1.6
1.4
20
0
40
80
100
1.2
1.0
V
TH
V
TL
Receiver Input Thresholds
DC ELECTRICAL CHARACTERISTICS
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
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
Power Supply
V
CC
Supply Current
No Load (All Drivers V
IN
= 5V)(Note 2)
0.6
1.1
mA
No Load (All Drivers V
IN
= 0V) (Note 2)
0.8
1.3
mA
Shutdown (Note 3)
80.0
120.0
A
On/Off Threshold Low
1.4
0.8
V
On/Off Threshold High
2.0
1.4
V
The
denotes specifications which apply over the full operating
temperature range. V
CC
= 5V, C1 = C2 = C3 = C4 = 0.1F, unless otherwise noted.
The
denotes specifications which apply over the full operating temperature range.
V
CC
= 5V, C1 = C2 = C3 = C4 = 0.1F, unless otherwise noted.
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LTC1347
1347fa
TYPICAL PERFOR A CE CHARACTERISTICS
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W
TEMPERATURE (C)
0
SUPPLY CURRENT (mA)
60
20
16
14
12
10
8
6
4
2
0
1347 G04
20
70
10
30
40
50
3 DRIVERS LOADED
R
L
= 3k
1 DRIVER LOADED
R
L
= 3k
V
CC
Supply Current
TEMPERATURE (C)
40
0
SHORT-CIRCUIT CURRENT (mA)
4
8
10
12
40
20
1347 G06
6
0
80
14
16
18
20
60
20
100
I
SC
+
I
SC
Driver Short-Circuit Current
TEMPERATURE (C)
0
LEAKAGE CURRENT (
A)
60
45
40
35
30
25
20
15
10
5
0
1347 G05
20
70
10
30
40
50
V
OUT
= 20V
V
OUT
= 20V
Driver Leakage in Shutdown
Receiver Short-Circuit Current
TEMPERATURE (C)
40
10
SHORT-CIRCUIT CURRENT (mA)
30
60
0
40
60
1347 G07
20
50
40
20
20
80
100
I
SC
I
SC
+
Driver Output Waveforms
Receiver Output Waveforms
DRIVER
OUTPUT
R
L
= 3k
C
L
= 2500pF
1347 G08
1347 G09
RECEIVER
OUTPUT
C
L
= 51pF
INPUT
DRIVER
OUTPUT
R
L
= 3k
INPUT
V
CC
: 5V Input Supply Pin. Supply current is typically 80A
in the Shutdown mode. This pin should be decoupled with
a 0.1F ceramic capacitor.
GND: Ground Pin.
ON/OFF: TTL/CMOS Compatible Shutdown Pin. A logic
low puts the device in the Shutdown mode with all receiv-
ers kept alive, and the supply current is 80A. All driver
outputs are in high impedance state. This pin cannot float.
V
+
: Positive Supply Output (RS232 Drivers).
V
+
2V
CC
1V. This pin requires an external capacitor C
= 0.1F for charge storage. The capacitor may be tied to
ground or V
CC
. With multiple devices, the V
+
and V
pins
may be paralleled 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 = 0.1F for charge storage.
C1
+
, C1
, C2
+
, C2
: Commutating Capacitor Inputs. These
pins require two external capacitors C = 0.1F: one from
C1
+
to C1
, and another from C2
+
to C2
. To maintain
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LTC1347
1347fa
charge pump efficiency, the capacitor's effective series
resistance should be less than 2.
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. All receivers are kept alive in Shutdown.
0.8V
V
CC
0V
2.4V
RX
INPUT
RX
OUTPUT
1.3V
t
HLR
1.7V
t
LHR
1347 F02
V
CC
0V
SWITCHI G TI E WAVEFOR S
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Figure 1. Driver Propagation Delay Timing
1.4V
0V
V
CC
0V
V
+
V
0V
DRIVER
INPUT
DRIVER
OUTPUT
1.4V
t
HLD
t
LHD
1347 F01
Figure 2. Receiver Propagation Delay Timing
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