LTC1350
3.3V Low Power
EIA/TIA-562 3-Driver/
5-Receiver Transceiver
FEATURES
■
■
DESCRIPTIO
■
■
■
■
■
■
■
■
Low Supply Current: 300µA
Receivers 4 and 5 Kept Alive
in Shutdown: 35µA
ESD Protection:
±10kV
Operates from a Single 3.3V Supply
Uses Small Capacitors: 0.1µF
Operates to 120kBaud
Three-State Outputs are High Impedance
When Off
Output Overvoltage Does Not Force Current
Back into Supplies
EIA/TIA-562 I/O Lines Can Be Forced to
±25V
Without Damage
Flowthrough Architecture
The LTC
®
1350 is a 3-driver/5-receiver EIA/TIA-562
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 only 35µA. All RS232 outputs assume
a high impedance state in Shutdown or with the power
off.
The LTC1350 is fully compliant with all data rate and
overvoltage EIA/TIA-562 specifications. The transceiver
can operate up to 120kbaud with a 1000pF and 3kΩ load.
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.
APPLICATIO S
■
■
Notebook Computers
Palmtop Computers
TYPICAL APPLICATIO
V
+
V
CC
C1
+
C1
–
DR1 OUT
RX1 IN
DR2 OUT
RX2 IN
RX3 IN
RX4 IN
DR3 OUT
RX5 IN
ON/OFF
NC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
LTC1350
3-Drivers/5-Receivers with Shutdown
28
27
26
25
24
23
22
21
20
19
18
17
16
15
LTC1350 • TA01
Quiescent and Shutdown Supply Current
vs Temperature
600
500
QUIESCENT CURRENT (µA)
V
–
C2
+
C2
–
DR1 IN
RX1 OUT
DR2 IN
RX2 OUT
RX3 OUT
RX4 OUT
DR3 IN
RX5 OUT
GND
NC
NC
TEST CONDITION: V
CC
= 3.3V
ALL DRIVER INPUTS TIED TO V
CC
400
300
200
100
0
–40 –20
U
85
75
65
55
45
SHUTDOWN CURRENT
35
0
100
SHUTDOWN CURRENT (µA)
U
U
QUIESCENT
CURRENT
40
20
60
0
TEMPERATURE (˚C)
80
LTC1350 • TA02
1350fa
1
LTC1350
ABSOLUTE
AXI U
RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
V
+
1
V
CC
2
C1
+
3
28 V–
27 C2+
26 C2–
25 DR1 IN
24 RX1 OUT
23 DR2 IN
22 RX2 OUT
21 RX3 OUT
20 RX4 OUT
19 DR3 IN
18 RX5 OUT
17 GND
16 NC
15 NC
NW PACKAGE
28-LEAD PDIP
Supply Voltage (V
CC
) ................................................ 5V
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 (LTC1350C) ........................ 0°C to 70°C
Industrial (LTC1350I) ........................ – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
ORDER PART
NUMBER
LTC1350CG
LTC1350CNW
LTC1350CSW
LTC1350IG
LTC1350INW
LTC1350ISW
C1– 4
DR1 OUT 5
RX1 IN 6
DR2 OUT 7
RX2 IN 8
RX3 IN 9
RX4 IN 10
DR3 OUT 11
RX5 IN 12
ON/OFF 13
NC 14
G PACKAGE
28-LEAD SSOP
SW PACKAGE
28-LEAD PLASTIC SO WIDE
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.
DC ELECTRICAL CHARACTERISTICS
PARAMETER
Any Driver
Output Voltage Swing
Logic Input Voltage Level
Logic Input Current
Output Short-Circuit Current
Output Leakage Current
Any Receiver
Input Voltage Thresholds
Hysteresis
Input Resistance
Output Voltage
Output Short-Circuit Current
Output Leakage Current
CONDITIONS
3k to GND
The
●
denotes specifications which apply over the full operating
temperature range. V
CC
= 3.3V, C1 = C2 = C3 = C4 = 0.1µF, unless noted.
MIN
Positive
Negative
●
●
●
●
●
●
TYP
4.5
– 4.5
1.4
1.4
MAX
UNITS
V
V
V
V
µA
µA
mA
µA
V
V
V
kΩ
V
V
mA
µA
3.7
– 3.7
2.0
Input Low Level (V
OUT
= High)
Input High Level (V
OUT
= Low)
V
IN
= V
CC
V
IN
= 0V
V
OUT
= 0V
Shutdown (Note 3), V
OUT
=
±20V
Input Low Threshold
Input High Threshold
V
IN
=
±10V
Output Low, I
OUT
= – 1.6mA (V
CC
= 3.3V)
Output High, I
OUT
= 160µA (V
CC
= 3.3V)
Sinking Current, V
OUT
= V
CC
Shutdown (Note 3), 0V
≤
V
OUT
≤
V
CC
0.8
5
–5
±9
±10
10
1.3
1.7
0.4
5
0.2
3.2
– 20
1
500
●
●
●
●
●
●
0.8
0.1
3
3.0
–3
2.4
1
7
0.4
10
2
U
1350fa
W
U
U
W W
W
LTC1350
DC ELECTRICAL CHARACTERISTICS
PARAMETER
Power Supply Generator
V
+
Output Voltage
V
–
Output Voltage
Supply Rise Time
Power Supply
V
CC
Supply Current
CONDITIONS
I
OUT
= 0mA
I
OUT
= 5mA
I
OUT
= 0mA
I
OUT
= – 5mA
Shutdown to Turn-On
The
●
denotes specifications which apply over the full operating
temperature range. V
CC
= 3.3V, C1 = C2 = C3 = C4 = 0.1µF, unless noted.
MIN
TYP
5.7
5.5
– 5.3
– 5.0
0.2
●
●
●
●
●
●
●
●
MAX
UNITS
V
V
V
V
ms
No Load (All Drivers V
IN
= V
CC
)(Note 2) 0°C
≤
T
A
≤
70°C
No Load (All Drivers V
IN
= 0)(Note 2) 0°C
≤
T
A
≤
70°C
No Load (All Drivers V
IN
= V
CC
)(Note 2) 0°C
≤
T
A
≤
85°C
No Load (All Drivers V
IN
= V
CC
)(Note 2) – 40°C
≤
T
A
≤
0°C
No Load (All Drivers V
IN
= 0)(Note 2) – 40°C
≤
T
A
≤
85°C
Shutdown (Note 3)
ON/OFF Threshold Low
ON/OFF Threshold High
2.0
0.3
0.5
0.3
0.3
0.5
35
1.4
1.4
0.6
1.0
1.0
1.5
1.5
50
0.8
mA
mA
mA
mA
mA
µA
V
V
AC CHARACTERISTICS
PARAMETER
Slew Rate
Driver Propagation Delay
(TTL to EIA/TIA-562)
Receiver Propagation Delay
(EIA/TIA-562 to TTL)
The
●
denotes specifications which apply over the full operating temperature range.
V
CC
= 5V, C1 = C2 = C3 = C4 = 0.1µF, unless noted.
CONDITIONS
R
L
= 3k, C
L
= 51pF
R
L
= 3k, C
L
= 1000pF
t
HLD
(Figure 1)
t
LHD
(Figure 1)
t
HLR
(Figure 2)
t
LHR
(Figure 2)
MIN
3
●
●
●
●
TYP
8
5
2
2
0.3
0.3
MAX
30
3.5
3.5
0.8
0.8
UNITS
V/µs
V/µs
µs
µs
µs
µs
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.
Note 3:
Supply current measurement in Shutdown mode is performed
with V
ON/OFF
= 0V.
1350fa
3
LTC1350
TYPICAL PERFOR A CE CHARACTERISTICS
Driver Output Voltage
vs Temperature
5
4
DRIVER OUTPUT VOLTAGE (V)
3
2
1
0
–1
–2
–3
–4
–5
–40 –20
V
CC
= 3.3V
OUTPUT HIGH
THRESHOLD VOLTAGE (V)
1.8
1.6
1.4
1.2
1.0
–40 –20
SUPPLY CURRENT (mA)
ALL DRIVERS WITH LOAD, R
L
= 3k
V
CC
= 3.3V
OUTPUT LOW
40
20
0
60
TEMPERATURE (°C)
V
CC
Supply Current
vs Temperature
5.0
4.5
4.0
R
L
= 3k
3 DRIVERS LOADED
LEAKAGE CURRENT (µA)
45
40
35
30
25
20
15
10
5
40
20
0
60
TEMPERATURE (°C)
80
100
0
SHORT-CIRCUIT CURRENT (mA)
SUPPLY CURRENT (mA)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
–40 –20
R
L
= 3k
1 DRIVER LOADED
Receiver Short-Circuit Current
vs Temperature
40
35
30
25
20
15
10
5
0
–40 –20
0
I
SC+
I
SC–
SHORT-CIRCUIT CURRENT (mA)
40
60
20
TEMPERATURE (˚C)
4
U W
80
LTC1350 • TPC01
LTC1350 • TPC04
Receiver Input Thresholds
vs Temperature
2.2
2.0
30
25
20
15
10
5
0
40
20
60
0
TEMPERATURE (˚C)
80
100
Supply Current vs Data Rate
V
CC
= 3.3V
R
L
= 3k
C
L
= 2500pF
3 DRIVERS ACTIVE
V
TH+
V
TH–
100
0
20
80 100
60
40
DATA RATE (k Baud)
120
140
LT1350 • TPC02
LTC1350 • TPC03
Driver Leakage in Shutdown
vs Temperature
16
14
12
10
8
6
4
2
60
70
Driver Short-Circuit Current
vs Temperature
I
SC–
V
OUT
= –20V
I
SC+
V
OUT
= 20V
0
10
30
20
40
50
TEMPERATURE (°C)
0
–40 –20
0
40
60
20
TEMPERATURE (˚C)
80
100
LTC1350 • TPC05
LTC1350 • TPC06
Driver Output Waveforms
DRIVER
OUTPUT
R
L
= 3k
C
L
= 1000pF
DRIVER
OUTPUT
R
L
= 3k
Receiver Output Waveform
RECEIVER
OUTPUT
C
L
= 50pF
INPUT
INPUT
LTC1350 • TPC08
LTC1350 • TPC09
80
100
LTC1350 • TPC07
1350fa
LTC1350
PI FU CTIO S
V
CC
:
3.3V 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 the Shutdown mode with receivers
4 and 5 kept alive and the supply current equal to 35µA. All
driver and other receiver outputs are in high impedance
state. This pin cannot float.
V
+
:
Positive Supply Output. V
+
≅
2V
CC
– 1V. This pin
requires an external capacitor (C = 0.1µF) 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 a large number of devices,
increasing the size of the shared common storage
capacitors is recommended to reduce ripple.
V
–
:
Negative Supply Output. V
–
≅
– (2V
CC
– 1.3V). 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.
DR IN:
EIA/TIA-562 Driver Input Pins. Inputs are TTL/
CMOS compatible. Inputs should not be allowed to float.
Tie unused inputs to V
CC
.
DR OUT:
Driver Outputs at EIA/TIA-562 Voltage Levels.
Outputs are in a high impedance state when in the 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 Levels.
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
DR
INPUT
DR
OUTPUT
t
LHD
V
CC
1.4V
1.4V
0V
V
+
0V
t
HLD
LTC1350 • F01
Figure 1. Driver Propagation Delay Timing
RX
INPUT
RX
OUTPUT
t
LHR
1.7V
Figure 2. Receiver Propagation Delay Timing
W
W
U
U
U
U
0V
V
–
V
CC
1.3V
0V
2.4V
0.8V
t
HLR
V
CC
0V
LTC1350 • F02
1350fa
5
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