LTC1321/LTC1322/LTC1335
RS232/EIA562/RS485
Transceivers
FEATURES
s
s
DESCRIPTIO
s
s
s
s
s
s
s
s
s
s
s
s
s
LTC1321: 2-EIA562/RS232 Transceivers/2-RS485
Transceivers
LTC1322: 4-EIA562/RS232 Transceivers/2-RS485
Transceivers
LTC1335: 4-EIA562 Transceivers/2-RS485
Transceivers with OE
LTC1321/LTC1322 Have the Same Pinout as
SP301/SP302
LTC1335 Features Receiver Three-State Outputs
Low Supply Current:
1mA Typical
15µA Supply Current in Shutdown
120kBaud in EIA/TIA-562 or RS232 Mode
10MBaud in RS485/RS422 Mode
Self-Testing Capability in Loopback Mode
Power-Up/Down Glitch-Free Outputs
Driver Maintains High Impedance in Three-State,
Shutdown or With Power Off
Thermal Shutdown Protection
I/O Lines Can Withstand
±25V
Withstands Repeated 10kV ESD Pulses
The LTC1321/LTC1322/LTC1335 are low power CMOS
bidirectional transceivers, each featuring two reconfigurable
interface ports. Each can be configured as two RS485
differential ports, as two single-ended ports, or as one
RS485 differential port and one single-ended port. The
LTC1321/LTC1322 can provide RS232 or EIA562 compat-
ible single-ended outputs; the LTC1335 provides EIA562
compatible outputs and additionally includes an output
enable pin, allowing the receiver logic level outputs to be
three-stated.
The RS232/EIA562 transceivers operate to 120kbaud and
are in full compliance with EIA/TIA-562 specification. The
RS485 transceivers operate to 10Mbaud and are in full
compliance with RS485 and RS422 specifications. All
interface drivers feature short-circuit and thermal shut-
down protection. An enable pin allows RS485 driver
outputs to be forced into high impedance which is main-
tained even when the outputs are forced beyond supply
rails or power is off. Both driver outputs and receiver
inputs feature
±10kV
ESD protection. A loopback mode
connects the driver outputs back to the receiver inputs for
diagnostic self-test.
The LTC1321/LTC1322 can support RS232 voltage levels
when 6.5V
≤
V
DD
≤
10V and – 6.5V
≥
V
EE
≥
– 10V. The
LTC1335 supports receiver output enable but not RS232
levels. A shutdown mode reduces the I
CC
supply current
to 15µA.
APPLICATIONS
s
s
s
Low Power RS485/RS422/EIA562/RS232 Interface
Cable Repeater
Level Translator
TYPICAL APPLICATI
V
CC1
5V
RX OUT
DR ENABLE
DR IN
5V
5V
DR IN
DR IN
RX OUT
RX OUT
V
EE1
–5V
24
1
22
21
20
19
18
17
16
15
14
13
2
3
120Ω
4
5
6
LTC1322
7
8
9
10
11
12
5V
0V
RS485 INTERFACE
120Ω
11
10
9
8
5V
7
6
3
2
5
4
12
LTC1322
4000-FT 24-GAUGE TWISTED PAIR
EIA562 INTERFACE
0V
U
24
1
15
16
17
19
18
22
23
20
21
13
V
CC2
5V
RX OUT
DR ENABLE
DR IN
5V
5V
RX OUT
RX OUT
DR IN
DR IN
V
EE2
–5V
1321/22/35 TA01
UO
U
1
LTC1321/LTC1322/LTC1335
ABSOLUTE
AXI U
RATI GS
Output Voltage
Drivers ................................................. – 25V to 25V
Receivers ............................... – 0.3V to (V
CC
+ 0.3V)
Output Short-Circuit Duration ......................... Indefinite
Operating Temperature Range
LTC1321C/LTC1322C/LTC1335C ......... 0°C to 70°C
LTC1321I/LTC1322I/LTC1335I ......... – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................ 300°C
Supply Voltage
V
CC
.................................................................... 6.5V
V
DD
(LTC1321/LTC1322 Only) ........................... 10V
V
EE
................................................................... – 10V
Input Voltage
Drivers ................................... – 0.3V to (V
CC
+ 0.3V)
Receivers ............................................. – 25V to 25V
ON/OFF, LB, SEL1,
SEL2, OE ............................ – 0.3V to (V
CC
+ 0.3V)
PACKAGE/ORDER I FOR ATIO
2 RS485 DRIVERS/RECEIVERS
2 EIA/TIA-562 DRIVERS/RECEIVERS
2 RS485 DRIVERS/RECEIVERS
4 EIA/TIA-562 DRIVERS/RECEIVERS
TOP VIEW
V
DD
B1
A1
Z1
Y1
SEL1
SEL2
Y2
Z2
1
2
3
4
5
6
7
8
9
24 V
CC
23 NC
22 R
A1
21 DE1
20 D
Y1
19 LB
18 ON/OFF
17 D
Y2
16 DE2
15 R
A2
14 NC
13 V
EE
S PACKAGE
24-LEAD PLASTIC SOL
V
DD
B1
A1
Z1
Y1
SEL1
SEL2
Y2
Z2
1
2
3
4
5
6
7
8
9
A2 10
B2 11
GND 12
N PACKAGE
24-LEAD PLASTIC DIP
A2 10
B2 11
GND 12
N PACKAGE
24-LEAD PLASTIC DIP
T
JMAX
= 125°C,
θ
JA
= 75°C/W (N)
T
JMAX
= 125°C,
θ
JA
= 85°C/W (S)
T
JMAX
= 125°C,
θ
JA
= 75°C/W (N)
T
JMAX
= 125°C,
θ
JA
= 85°C/W (S)
ORDER PART
NUMBER
LTC1321CN
LTC1321CS
LTC1321IN
LTC1321IS
Consult factory for Military grade parts.
ORDER PART
NUMBER
LTC1322CN
LTC1322CS
LTC1322IN
LTC1322IS
2
U
U
W
W W
U
W
2 RS485 DRIVERS/RECEIVERS
4 EIA/TIA-562 DRIVERS/RECEIVERS
TOP VIEW
24 V
CC
23 R
B1
22 R
A1
21 D
Z1
/DE1
20 D
Y1
19 LB
18 ON/OFF
17 D
Y2
16 D
Z2
/DE2
15 R
A2
14 R
B2
13 V
EE
S PACKAGE
24-LEAD PLASTIC SOL
OE
B1
A1
Z1
Y1
SEL1
SEL2
Y2
Z2
1
2
3
4
5
6
7
8
9
TOP VIEW
24 V
CC
23 R
B1
22 R
A1
21 D
Z1
/DE1
20 D
Y1
19 LB
18 ON/OFF
17 D
Y2
16 D
Z2
/DE2
15 R
A2
14 R
B2
13 V
EE
S PACKAGE
24-LEAD PLASTIC SOL
A2 10
B2 11
GND 12
N PACKAGE
24-LEAD PLASTIC DIP
T
JMAX
= 125°C,
θ
JA
= 75°C/W (N)
T
JMAX
= 125°C,
θ
JA
= 85°C/W (S)
ORDER PART
NUMBER
LTC1335CN
LTC1335CS
LTC1335IN
LTC1335IS
LTC1321/LTC1322/LTC1335
DC ELECTRICAL CHARACTERISTICS
V
CC
= V
DD
(LTC1321/LTC1322) = 5V
±5%,
V
EE
= – 5V
±5%
(Notes 2, 3)
SYMBOL
V
OD1
V
OD2
∆V
OD
V
OC
∆V
OC
I
OSD
I
OZD
V
O
I
OSD
V
IH
V
IL
I
IN
PARAMETER
Differential Driver Output Voltage (Unloaded)
Differential Driver Output Voltage (With Load)
Change in Magnitude of Driver Differential
Output Voltage for Complementary Output States
Driver Common-Mode Output Voltage
Change in Magnitude of Driver Common-Mode
Output Voltage for Complementary Output States
Driver Short-Circuit Current
Three-State Output Current (Y, Z)
Output Voltage Swing
Output Short-Circuit Current
Input High Voltage
Input Low Voltage
Input Current
CONDITIONS
I
O
= 0
Figure 1, R = 50Ω (RS422)
Figure 1, R = 27Ω (RS485)
Figure 1, R = 27Ω or R = 50Ω
Figure 1, R = 27Ω or R = 50Ω
Figure 1, R = 27Ω or R = 50Ω
– 7V
≤
V
O
≤
12V, V
O
= HIGH
– 7V
≤
V
O
≤
12V, V
O
= LOW (Note 4)
– 7V
≤
V
O
≤
12V
Figure 4, R
L
= 3k, Positve
Figure 4, R
L
= 3k, Negative
V
O
= 0V
D, DE, ON/OFF, SEL1, SEL2, LB
OE (LTC1335)
D, DE, ON/OFF, SEL1, SEL2, LB
OE (LTC1335)
D, SEL1, SEL2
DE, ON/OFF, LB
OE (LTC1335)
– 7V
≤
V
CM
≤
7V, Commercial
– 7V
≤
V
CM
≤
7V, Industrial
V
CM
= 0V
– 7V
≤
V
IN
≤
12V
– 7V
≤
V
IN
≤
12V
Input Low Threshold
Input High Threshold
V
IN
=
±10V
I
O
= – 3mA, V
IN
= 0V, SEL1 = SEL2 = LOW
I
O
= 3mA, V
IN
= 3V, SEL1 = SEL2 = LOW
0V
≤
V
O
≤
V
CC
ON/OFF = 0V
OE = V
CC
(LTC1335)
q
q
q
q
q
q
q
q
q
q
q
q
q
q
MIN
TYP
MAX
5
UNITS
V
V
V
V
V
V
mA
mA
µA
V
V
RS485 Driver (SEL1 = SEL2 = HIGH)
2.0
1.5
5
5
0.2
3
0.2
35
10
±5
3.7
– 3.7
4.2
– 4.3
±11
2
2
0.8
0.8
–4
4
±10
– 15
15
±60
250
250
±500
EIA/TIA-562 Driver (SEL1 = SEL2 = LOW)
q
q
q
mA
V
V
V
V
µA
µA
µA
V
V
mV
mA
kΩ
V
V
V
kΩ
V
Driver Inputs and Control Inputs
q
q
q
q
q
q
q
RS485 Receiver (SEL1 = SEL2 = HIGH)
V
TH
∆V
TH
I
IN
R
IN
V
TH
∆V
TH
R
IN
V
OH
V
OL
I
OSR
I
OZR
Differential Input Threshold Voltage
Input Hysteresis
Input Current (A, B)
Input Resistance
Receiver Input Voltage Threshold
Receiver Input Hysteresis
Receiver Input Resistance
Receiver Output High Voltage
Receiver Output Low Voltage
Short-Circuit Current
Three-State Output Current
q
q
q
q
q
– 0.2
– 0.3
70
0.2
0.3
±1
12
0.8
0.1
3
3.5
7
24
1.1
1.7
0.6
5
4.6
0.2
0.4
85
±10
±10
EIA/TIA-562 Receiver (SEL1 = SEL2 = LOW)
q
q
q
2.4
1.0
7
Receiver Output
V
mA
µA
µA
3
LTC1321/LTC1322/LTC1335
DC ELECTRICAL CHARACTERISTICS
V
CC
= V
DD
(LTC1321/LTC1322) = 5V
±5%,
V
EE
= – 5V
±5%
(Notes 2, 3)
SYMBOL
I
CC
I
DD
I
EE
PARAMETER
V
CC
Supply Current
V
DD
Supply Current (LTC1321/LTC1322)
V
EE
Supply Current
CONDITIONS
No Load (SEL1 = SEL2 = HIGH)
Shutdown, ON/OFF = 0V
No Load (SEL1 = SEL2 = LOW)
Shutdown, ON/OFF = 0V
No Load (SEL1 = SEL2 = HIGH)
Shutdown, ON/OFF = 0V
q
q
q
q
q
q
MIN
TYP
1000
15
300
0.1
– 1000
– 0.1
MAX
2000
50
1000
50
– 2000
– 50
UNITS
µA
µA
µA
µA
µA
µA
Supply Currents
AC
ELECTRICAL CHARACTERISTICS
DC
SYMBOL
SR
t
T
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
t
SKEW
t
r
, t
f
t
ZL
t
ZH
t
LZ
t
HZ
t
PLH
t
PHL
t
SKEW
t
ZL
t
ZH
t
LZ
t
HZ
PARAMETER
Slew Rate
Transition Time
Driver Input to Output
Driver Input to Output
Receiver Input to Output
Receiver Input to Output
Driver Input to Output
Driver Input to Output
Driver Output to Output
Driver Rise or Fall Time
Driver Enable to Output Low
Driver Enable to Output High
Driver Disable from Low
Driver Disable from High
Receiver Input to Output
Receiver Input to Output
Differential Receiver Skew,
t
PLH
-t
PHL
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable from Low
Receiver Disable from High
EIA/TIA-562 Mode (SEL1 = SEL2 = LOW)
V
CC
= V
DD
(LTC1321/LTC1322) = 5V
±5%,
V
EE
= – 5V
±5%
(Notes 2, 3)
CONDITIONS
Figure 4, R
L
= 3k, C
L
= 15pF
Figure 4, R
L
= 3k, C
L
= 1000pF
Figure 4, R
L
= 3k, C
L
= 2500pF
Figures 4,10, R
L
= 3k, C
L
= 15pF
Figures 4,10, R
L
= 3k, C
L
= 15pF
Figures 5,11
Figures 5,11
Figures 2,7, R
L
= 54Ω, C
L
= 100pF
Figures 2,7, R
L
= 54Ω, C
L
= 100pF
Figures 2,7, R
L
= 54Ω, C
L
= 100pF
Figures 2,7, R
L
= 54Ω, C
L
= 100pF
Figures 3,8, C
L
= 100pF, S1 Closed
Figures 3,8, C
L
= 100pF, S2 Closed
Figures 3,8, C
L
= 15pF, S1 Closed
Figures 3,8, C
L
= 15pF, S2 Closed
Figures 2,9, R
L
= 54Ω, C
L
= 100pF
Figures 2,9, R
L
= 54Ω, C
L
= 100pF
Figures 2,9, R
L
= 54Ω, C
L
= 100pF
Figures 6,12, C
L
= 15pF, S1 Closed
Figures 6,12, C
L
= 15pF, S2 Closed
Figures 6,12, C
L
= 15pF, S1 Closed
Figures 6,12, C
L
= 15pF, S2 Closed
q
q
q
q
q
q
q
MIN
TYP
14
7
1.9
0.6
0.6
0.3
0.4
MAX
30
3.1
4
4
6
6
70
70
15
40
90
90
90
90
140
140
UNITS
V/µs
V/µs
µs
µs
µs
µs
µs
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
4
0.22
RS485 Mode (SEL1 = SEL2 = HIGH)
q
q
q
q
q
q
q
q
q
q
q
20
20
3
40
40
5
15
50
50
50
60
20
20
60
70
10
40
40
40
50
Receiver Output Enable/Disable (LTC1335)
q
q
q
q
90
90
90
90
ns
ns
ns
ns
The
q
denotes specifications which apply over the full operating
temperature range.
Note 1:
Absolute maximum ratings are those values beyond which the
safety of the device cannot be guaranteed.
Note 2:
All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to device ground unless
otherwise specified.
Note 3:
All typicals are given at V
CC
= V
DD
(LTC1321/LTC1322) = 5V,
V
EE
= – 5V, and T
A
= 25°C.
Note 4:
Short-circuit current for RS485 driver output low state folds back
above V
CC
. Peak current occurs around V
O
= 3V.
4
LTC1321/LTC1322/LTC1335
TYPICAL PERFORMANCE CHARACTERISTICS
RS485 Driver Differential Output
Voltage vs Temperature
2.6
DIFFERENTIAL OUTPUT VOLTAGE (V)
2.5
2.4
2.3
2.2
2.1
2.0
1.9
1.8
1.7
DIFFERENTIAL OUTPUT CURRENT (mA)
R
L
= 54Ω
40
30
20
TIME (µs)
1.6
–50 –25
50
25
0
75
TEMPERATURE (°C)
RS485 Driver Output High Voltage
vs Output Current
–80
T
A
= 25°C
–70
100
120
OUTPUT SHORT-CIRCUIT CURRENT (mA)
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
–60
–50
–40
–30
–20
–10
0
0
1
3
OUTPUT VOLTAGE (V)
2
4
5
1321 G04
EIA562 Driver Output Voltage
vs Temperature
5
4
3
OUTPUT VOLTAGE (V)
OUTPUT HIGH
OUTPUT VOLTAGE (V)
8
6
4
2
0
–2
–4
–6
R
L
= 3k
T
A
= 25°C
V
EE
= –V
DD
OUTPUT SHORT-CIRCUIT CURRENT (mA)
2
1
0
–1
–2
–3
–4
–5
–50 –25
OUTPUT LOW
50
25
0
75
TEMPERATURE (°C)
100
125
R
L
= 3k
U W
100
125
1321 G01
RS485 Driver Differential Output
Current vs Output Voltage
70
T
A
= 25°C
60
12
15
RS485 Driver Skew vs
Temperature
50
9
6
3
10
0
0
3
4
DIFFERENTIAL OUTPUT VOLTAGE (V)
1
2
5
0
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
1321 G02
1321 G03
RS485 Driver Output Low Voltage
vs Output Current
160
T
A
= 25°C
RS485 Driver Output Short-Circuit
Current vs Temperature
140
120
100
80
60
40
–50 –25
80
60
40
20
0
SINK
(V
OUT
= 5V)
SOURCE
(V
OUT
= 0V)
0
1
2
3
4
OUTPUT VOLTAGE (V)
5
1321 G05
50
25
75
0
TEMPERATURE (°C)
100
125
1321 G19
EIA562 Driver Output Voltage
vs Supply Voltage
10
18
EIA562 Driver Output Short-Circuit
Current vs Temperature
V
OUT
= 0V
16
14
12
10
SINK
8
6
–50 –25
SOURCE
OUTPUT HIGH
OUTPUT LOW
–8
–10
4
5
7
8
9
6
V
DD
SUPPLY VOLTAGE (V)
10
1321 G08
50
25
75
0
TEMPERATURE (°C)
100
125
1321 G07
1321 G09
5
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