Name: LTC1387CG
SKU: LTC1387CG
Price: 5.86152 USD
Availability: OutOfStock

LTC1387

Single 5V RS232/RS485

Multiprotocol Transceiver

The LTC

1387 is a low power reconfigurable CMOS bidi-

rectional transceiver. It can be configured as an RS485

differential port or as two RS232 single-ended ports. An

onboard charge pump uses four 0.1µF capacitors to

generate boosted positive and negative supplies, allowing

the RS232 drivers to meet ±5V output swing require-

ments with only a single 5V supply. A shutdown mode

reduces the I

supply current to 5µA.

The RS232 transceivers are in full compliance with RS232

specification. The RS485 transceiver is in full compliance

with RS485 and RS422 specifications. The RS485 re-

ceiver assumes a known output state when the inputs are

floating or shorted to ground. All interface drivers feature

short-circuit and thermal shutdown protection. An enable

pin allows RS485 driver outputs to be forced into high

impedance which is maintained even when the outputs are

forced beyond supply rails or the power is off. A loop back

mode allows the driver outputs to be connected back to the

receiver inputs for diagnostic self-test.

The LTC1387 is available in 20-pin plastic SSOP and SW

packages.

ESCRIPTIO

■

Two RS232 Transceivers or One RS485 Transceiver

■

Operates from a Single 5V Supply

■

Guaranteed Receiver Output with Inputs

Floating or Shorted to Ground

■

Logic Selectable Fast/Slow RS485 Driver Slew Rate

■

Low Supply Current: 7mA Typical

■

5µA Supply Current in Shutdown

■

Self-Testing Capability in Loopback Mode

■

Separate Driver and Receiver Enable Controls

■

Driver Maintains High Impedance in Three-State,

Shutdown or with Power Off

■

Receiver Inputs Can Withstand ±25V

■

Point-of-Sale Terminals

■

Software Selectable Multiprotocol Interface Ports

■

Low Power RS485/RS422/RS232/EIA562 Interface

■

Cable Repeaters

■

Level Translators

APPLICATIONS

, LTC and LT are registered trademarks of Linear Technology Corporation.

ITY

DR ENABLE

SLEW

1920

CC1

120Ω

LTC1387

LTC1387 • TA01

RECOUT

RS485 INTERFACE

DR IN

LTC1387

RECOUT

DR ENABLE

DR IN

SLEW

120Ω

4000-FT 24-GAUGE TWISTED PAIR

ALL CAPACITORS: 0.1µF MONOLITHIC CERAMIC TYPE

212019

CC2

LTC1387

ARB

EXI T

ORDER PART

NUMBER

(Note 1)

Supply Voltage (V

) ............................................. 6.5V

Input Voltage

Drivers ................................... –0.3V to (V

+ 0.3V)

Receivers ............................................. –25V to 25V

485/232, ON, DXEN

RXEN, SLEW ........................... –0.3V to (V

+ 0.3V)

Output Voltage

Drivers ................................................. –18V to 18V

Receivers ............................... –0.3V to (V

+ 0.3V)

Short-Circuit Duration

Output ........................................................ Indefinite

, V

, C1

–

, C2

–

.......................... 30 sec

Operating Temperature Range

LTC1387C .............................................. 0°C to 70°C

LTC1387I ........................................... –40°C to 85°C

Storage Temperature Range ................ –65°C to 150°C

Lead Temperature (Soldering, 10 sec)................ 300°C

PACKAGE

RDER I FOR ATIO

Consult factory for Military grade parts.

JMAX

= 125°C, θ

= 120°C/W (G)

JMAX

= 125°C, θ

= 75°C/W (SW)

1

2

3

4

5

6

7

8

9

TOP VIEW

SW PACKAGE

20-LEAD PLASTIC SO

G PACKAGE

20-LEAD PLASTIC SSOP

20

19

18

17

16

15

14

13

12

11



–



DD

A

B

Y

Z

485/232

DXEN

GND



–



CC

A

B

Y

/SLEW

ON

RXEN

DC ELECTRICAL CHARACTERISTICS

LTC1387CG

LTC1387CSW

LTC1387IG

LTC1387ISW

= 25°C, V

= 5V, C1 = C2 = C3 = C4 = 0.1µF (Notes 2, 3), unless otherwise noted.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

RS485 Driver (485/232 = High, ON = DXEN = High)

OD1

Differential Driver Output Voltage (Unloaded) I

= 0 ● 6V

OD2

Differential Driver Output Voltage (With Load) Figure 1, R = 50Ω (RS422) ● 2.0 6 V

Figure 1, R = 27Ω (RS485) ● 1.5 6 V

∆V

Change in Magnitude of Driver Differential Figure 1, R = 27Ω or R = 50Ω ● 0.2 V

Output Voltage for Complementary Output States

Driver Common Mode Output Voltage Figure 1, R = 27Ω or R = 50Ω ● 3V

∆V

 Change in Magnitude of Driver Common Mode Figure 1, R = 27Ω or R = 50Ω ● 0.2 V

Output Voltage for Complementary Output States

OSD

Driver Short-Circuit Current V

= –7V, 12V; V

= High ● 35 250 mA

= –7V, 12V; V

= Low (Note 4) ● 10 250 mA

OZD

Three-State Output Current (Y, Z) –7V ≤ V

≤ 12V ±5 500 µA

RS232 Driver (485/232 = Low, ON = DXEN = High)

Output Voltage Swing Figure 4, R

= 3k, Positive ● 5 6.5 V

Figure 4, R

= 3k, Negative ● –5 –6.5 V

OSD

Output Short-Circuit Current V

= 0V ● ±17 ±60 mA

Driver Inputs and Control Inputs

Input High Voltage D

, D

, DXEN, RXEN, ON, 485/232, SLEW ● 2V

Input Low Voltage D

, D

, DXEN, RXEN, ON, 485/232, SLEW ● 0.8 V

Input Current D

, D

, DXEN, RXEN, ON, 485/232 ● ±0.1 ±10 µA

SLEW (Note 5)

● 5 15 µA

LTC1387

DC ELECTRICAL CHARACTERISTICS

= 25°C, V

= 5V, C1 = C2 = C3 = C4 = 0.1µF (Notes 2, 3), unless otherwise noted.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

RS485 Receiver (485/232 = High, ON = RXEN = High)

Differential Input Threshold Voltage –7V ≤ V

≤ 12V ● –0.20 0.20 V

∆V

Input Hysteresis V

= 0V 40 mV

Input Current (A, B) V

= 12V ● 1mA

= –7V ● –0.8 mA

Input Resistance –7V ≤ V

≤ 12V ● 12 24 kΩ

RS232 Receiver (485/232 = Low, ON = RXEN = High)

Receiver Input Voltage Threshold Input Low Threshold ● 0.8 V

Input High Threshold

● 2.4 V

∆V

Receiver Input Hysteresis 0.6 V

Receiver Input Resistance V

= ±10V 3 5 7 kΩ

Receiver Output (ON = RXEN = High)

Receiver Output High Voltage I

= –3mA, V

= 0V, 485/232 = Low ● 3.5 4.6 V

Receiver Output Low Voltage I

= 3mA, V

= 3V, 485/232 = Low ● 0.2 0.4 V

OSR

Short-Circuit Current 0V ≤ V

≤ V

● 785mA

OZR

Three-State Output Current RXEN = 0V ● ±0.1 ±10 µA

Power Supply Generator

Output Voltage No Load, ON = DXEN = RXEN = High 8 V

= –5mA, ON = DXEN = RXEN = High 7 V

Output Voltage No Load, ON = DXEN = RXEN = High –7.7 V

= 5mA, ON = DXEN = RXEN = High –7.0 V

Power Supply

Supply Current No Load, ON = DXEN = RXEN = High ● 725 mA

Shutdown, ON = DXEN = RXEN = 0V

● 5 100 µA

AC ELECTRICAL CHARACTERISTICS

= 25°C, V

= 5V, C1 = C2 = C3 = C4 = 0.1µF (Notes 2, 3), unless otherwise noted.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

RS232 Mode (ON = DXEN = RXEN = High, 485/232 = Low)

SR Slew Rate Figure 4, R

= 3k, C

= 15pF ● 30 V/µs

Figure 4, R

= 3k, C

= 1000pF ● 4V/µs

Transition Time Figure 4, R

= 3k, C

= 2500pF ● 0.22 1.9 3.1 µs

PLH

Driver Input to Output Figures 4, 10, R

= 3k, C

= 15pF ● 0.6 4 µs

PHL

Driver Input to Output Figures 4, 10, R

= 3k, C

= 15pF ● 0.6 4 µs

PLH

Receiver Input to Output Figures 5, 11 ● 0.3 6 µs

PHL

Receiver Input to Output Figures 5, 11 ● 0.4 6 µs

RS485 Mode (Fast Slew Rate, ON = DXEN = High, 485/232 = High, SLEW = High)

PLH

Driver Input to Output Figures 2, 7, R

= 54Ω, C

= 100pF ● 15 40 70 ns

PHL

Driver Input to Output Figures 2, 7, R

= 54Ω, C

= 100pF ● 15 40 70 ns

SKEW

Driver Output to Output Figures 2, 7, R

= 54Ω, C

= 100pF ● 515 ns

, t

Driver Rise or Fall Time Figures 2, 7, R

= 54Ω, C

= 100pF ● 31540 ns

Part #	LTC1387CG
Description	IC TXRX RS232/485/422 MULTIPRTCL
Category	IC
Availability	Out of Stock
Qty	0

LTC1387CG

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Technical Document