LTC1334
Single 5V RS232/RS485
Multiprotocol Transceiver
FEATURES
DESCRIPTIO
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Four RS232 Transceivers or Two RS485 The LTC 1334 is a low power CMOS bidirectional trans-
Transceivers on One Chip ceiver featuring two reconfigurable interface ports. It can
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Operates from a Single 5V Supply be configured as two RS485 differential ports, as two dual
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Withstands Repeated 10kV ESD Pulses RS232 single-ended ports or as one RS485 differential
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Uses Small Charge Pump Capacitors: 0.1m F port and one dual RS232 single-ended port. An onboard
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Low Supply Current: 8mA Typical charge pump requires four 0.1m F capacitors to generate
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10m A Supply Current in Shutdown boosted positive and negative supplies, allowing the RS232
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Self-Testing Capability in Loopback Mode drivers to meet the RS232 5V output swing requirement
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Power-Up/Down Glitch-Free Outputs with only a single 5V supply. A shutdown mode reduces
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Driver Maintains High Impedance in Three-State, the I supply current to 10m A.
CC
Shutdown or with Power Off
The RS232 transceivers are in full compliance with RS232
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Thermal Shutdown Protection
specifications. The RS485 transceivers are in full compli-
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Receiver Inputs Can Withstand 25V
ance with RS485 and RS422 specifications. All interface
drivers feature short-circuit and thermal shutdown pro-
U
tection. An enable pin allows RS485 driver outputs to be
APPLICATIO S
forced into high impedance, which is maintained even
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Low Power RS485/RS422/RS232/EIA562 Interface
when the outputs are forced beyond supply rails or power
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Software-Selectable Multiprotocol Interface Port
is off. Both driver outputs and receiver inputs feature
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Cable Repeaters
10kV ESD protection. A loopback mode allows the driver
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Level Translators
outputs to be connected back to the receiver inputs for
diagnostic self-test.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
2 1 28 27 27 28 1 2
3
3
LTC1334 LTC1334
26
26
V V
CC1 CC2
13
4
5V 5V
24 17
RS485 INTERFACE
5 12 RX OUT
RX OUT
23 18
120W
DR ENABLE 120W
DR ENABLE
11
6
22
19
DR IN
10 DR IN
7
4000-FT 24-GAUGE TWISTED PAIR
9 21
21 8
5V
5V
5V 5V
8
20
20 9
0V 5V
0V
5V
RS232 INTERFACE
4 24
19 11
RX OUT
DR IN
18 10 5 25
DR IN RX OUT
17 6 22
13
RX OUT
DR IN
16 12 7 23
RX OUT DR IN
15 14 14 15
ALL CAPACITORS: 0.1m F MONOLITHIC CERAMIC TYPE
LTC1334 TA01
1
U
ULTC1334
AB OLUEXAI U RAT GS /
S T I PACKAGE ORDER I FOR ATIO
(Note 1)
TOP VIEW
ORDER PART
Supply Voltage (V ) ............................................. 6.5V
CC
+ +
NUMBER
Input Voltage C1 1 28 C2
C1 2 27 C2
Drivers ................................... 0.3V to (V + 0.3V)
CC
V 3 26 V
DD CC
Receivers ............................................. 25V to 25V
LTC1334CG
A1 4 25 R
B1
ON/OFF, LB, SEL1, SEL2 ........ 0.3V to (V + 0.3V)
LTC1334CNW
CC B1 5 24 R
A1
Y1 6 23 D /DE1
Output Voltage Z1
LTC1334CSW
Z1 7 22 D
Y1
Drivers ................................................. 18V to 18V LTC1334IG
SEL1 8 21 LB
Receivers ............................... 0.3V to (V + 0.3V) LTC1334ISW
CC
SEL2 9 20 ON/OFF
Short-Circuit Duration
Z2 10 19 D
Y2
Y2 11 18 D /DE2
Z2
Output ........................................................ Indefinite
B2 12 17 R
+ + A2
V , V , C1 , C1 , C2 , C2 .......................... 30 sec
DD EE
A2 13 16 R
B2
Operating Temperature Range
GND 14 15 V
EE
Commercial ........................................... 0 C to 70 C
G PACKAGE NW PACKAGE
28-LEAD PLASTIC SSOP 28-LEAD PDIP WIDE
Industrial ............................................ 40 C to 85 C
SW PACKAGE
Storage Temperature Range ................ 65 C to 150 C
28-LEAD PLASTIC SO WIDE
Lead Temperature (Soldering, 10 sec)................ 300 C
T = 125 C, q = 90 C/W (G)
JMAX JA
T = 125 C, q = 56 C/W (NW)
JMAX JA
T = 125 C, q = 85 C/W (SW)
JMAX JA
Consult factory for Military grade parts.
DC ELECTRICAL CHARACTERISTICS The l denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T = 25 C. V = 5V, C1 = C2 = C3 = C4 = 0.1m F (Notes 2, 3)
A CC
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
RS485 Driver (SEL1 = SEL2 = High)
V Differential Driver Output Voltage (Unloaded) I = 0 l 6V
OD1 O
V Differential Driver Output Voltage (With Load) Figure 1, R = 50W (RS422) l 2.0 6 V
OD2
Figure 1, R = 27W (RS485) l 1.5 6 V
D V Change in Magnitude of Driver Differential Figure 1, R = 27W or R = 50W l 0.2 V
OD
Output Voltage for Complementary Output States
V Driver Common Mode Output Voltage Figure 1, R = 27W or R = 50W l 3V
OC
D V Change in Magnitude of Driver Common Mode Figure 1, R = 27W or R = 50W l 0.2 V
OC
Output Voltage for Complementary Output States
I Driver Short-Circuit Current 7V V 12V, V = High l 35 250 mA
OSD O O
7V V 12V, V = Low (Note 4) l 10 250 mA
O O
I Three-State Output Current (Y, Z) 7V V 12V l 5 500 m A
OZD O
RS232 Driver (SEL1 = SEL2 = Low)
V Output Voltage Swing Figure 4, R = 3k, Positive l 5 6.5 V
O L
= 3k, Negative l 5 6.5 V
Figure 4, R
L
I Output Short-Circuit Current V = 0V l 60 mA
OSD O
Driver Inputs and Control Inputs
V Input High Voltage D, DE, ON/OFF, SEL1, SEL2, LB l2V
IH
V Input Low Voltage D, DE, ON/OFF, SEL1, SEL2, LB l 0.8 V
IL
I Input Current D, SEL1, SEL2 l 10 m A
IN
DE, ON/OFF, LB l 4 15 m A
2
U WU U W W W