Datasheet

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LT1180A/LT1181A

11801afb

DESCRIPTIO

FEATURES

APPLICATIO S

TYPICAL APPLICATIO

Low Power 5V RS232

Dual Driver/Receiver with

0.1µF Capacitors

Output Waveforms

LT1180A • TA02

DRIVER

OUTPUT

= 3k

= 2500pF

RECEIVER

OUTPUT

= 50pF

INPUT

0.1µF

LOGIC

INPUTS

LOGIC

OUTPUTS

ON/OFF

5V INPUT

OUT

–

OUT

RS232 OUTPUT

RS232 INPUT

LT1180A • TA01

LT1180A

0.1µF

■

ESD Protection over ±10kV

■

Uses Small Capacitors: 0.1µF

■

120kBaud Operation for R

= 3k, C

= 2500pF

■

250kBaud Operation for R

= 3k, C

= 1000pF

■

Outputs Withstand ±30V Without Damage

■

CMOS Comparable Low Power: 40mW

■

Operates from a Single 5V Supply

■

Rugged Bipolar Design

■

Outputs Assume a High Impedance State When Off

or Powered Down

■

Meets All RS232 Specifications

■

Available With or Without Shutdown

■

Absolutely No Latch-up

■

Available in SO Package

■

Portable Computers

■

Battery-Powered Systems

■

Power Supply Generator

■

Terminals

■

Modems

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

TransZorb is a registered trademark of General Instruments, GSI

The LT

1180A/LT1181A are dual RS232 driver/receiver

pairs with integral charge pump to generate RS232 volt-

age levels from a single 5V supply. These circuits feature

rugged bipolar design to provide operating fault tolerance

and ESD protection unmatched by competing CMOS

designs. Using only 0.1µF external capacitors, these cir-

cuits consume only 40mW of power, and can operate to

120k baud even while driving heavy capacitive loads. New

ESD structures on the chip allow the LT1180A/LT1181A to

survive multiple ±10kV strikes, eliminating the need for

costly TransZorbs

on the RS232 line pins. The LT1180A/

LT1181A are fully compliant with EIA RS232 standards.

Driver outputs are protected from overload, and can be

shorted to ground or up to ±30V without damage. During

shutdown or power-off conditions, driver and receiver

outputs are in a high impedance state, allowing line

sharing.

The LT1181A is available in 16-pin DIP and SO packages.

The LT1180A is supplied in 18-pin DIP and SO packages

for applications which require shutdown.

Summary of content (12 pages)

PAGE 1
LT1180A/LT1181A Low Power 5V RS232 Dual Driver/Receiver with 0.1µF Capacitors U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ESD Protection over ±10kV Uses Small Capacitors: 0.
PAGE 2
LT1180A/LT1181A W W W AXI U U ABSOLUTE RATI GS (Note 1) Supply Voltage (VCC) ................................................ 6V V + ........................................................................ 13.2V V – ...................................................................... –13.2V Input Voltage Driver ........................................................... V – to V + Receiver ............................................... – 30V to 30V ON/OFF ..........................................
PAGE 3
LT1180A/LT1181A ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the operating temperature range (0°C ≤ TA ≤ 70°C for commercial grade, and – 40°C ≤ TA ≤ 85°C for industrial grade.
PAGE 4
LT1180A/LT1181A U W TYPICAL PERFOR A CE CHARACTERISTICS Driver Maximum Output Voltage vs Load Capacitance Driver Minimum Output Voltage vs Load Capacitance 8.0 Driver Output Voltage 10 –4.0 8 7.0 20kBAUD 6.5 60kBAUD 6.0 120kBAUD 5.5 DRIVER OUTPUT VOLTAGE (V) –4.5 PEAK OUTPUT VOLTAGE (V) PEAK OUTPUT VOLTAGE (V) 7.5 120kBAUD –5.0 60kBAUD –5.5 20kBAUD –6.0 –6.5 RL = 3k 6 VCC = 5.5V VCC = 5V VCC = 4.5V OUTPUT HIGH 4 2 0 OUTPUT LOW VCC = 4.5V VCC = 5V VCC = 5.5V –2 –4 –6 –8 5.
PAGE 5
LT1180A/LT1181A U W TYPICAL PERFOR A CE CHARACTERISTICS Receiver Short-Circuit Current Slew Rate vs Load Capacitance 16 14 40 12 RX ISC– 30 SLEW RATE (V/µs) SHORT-CIRCUIT CURRENT (mA) 50 RX ISC+ 20 10 8 +SLEW 6 –SLEW 4 10 2 0 –55 –25 50 25 0 75 TEMPERATURE (°C) 100 125 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.
PAGE 6
LT1180A/LT1181A U U U PI FU CTIO S TR1 IN, TR2 IN: RS232 Driver Input Pins. These inputs are TTL/CMOS compatible. Inputs should not be allowed to float. Tie unused inputs to VCC. TR1 OUT, TR2 OUT: Driver Outputs at RS232 Voltage Levels. Driver output swing meets RS232 levels for loads up to 3k. Slew rates are controlled for lightly loaded lines. Output current capability is sufficient for load conditions up to 2500pF.
PAGE 7
LT1180A/LT1181A UO TYPICAL APPLICATI Supporting an LT1039 (Triple Driver/Receiver) SHUTDOWN 5V 18 VCC ON/OFF 18 17 VCC LT1180A TTL INPUT TTL INPUT TTL OUTPUT 11 8 12 15 13 14 TTL INPUT ON/OFF LT1039 15 4 13 6 11 8 16 3 TTL INPUT + TTL INPUT RS232 INPUT TTL OUTPUT 1µF C1+ 4 C1– 5 + 1µF 6 RS232 INPUT TTL OUTPUT 14 5 5k 2 V+ V– C2 – GND 16 RS232 OUTPUT RS232 INPUT RS232 INPUT 30k TTL OUTPUT C2 + RS232 OUTPUT RS232 OUTPUT 30k 9 10 RS232 OUTPUT RS232 OUTPUT
PAGE 8
LT1180A/LT1181A U PACKAGE DESCRIPTIO J Package 16-Lead CERDIP (Narrow .300 Inch, Hermetic) (Reference LTC DWG # 05-08-1110) CORNER LEADS OPTION (4 PLCS) 0.840 (21.336) MAX 0.005 (0.127) MIN 0.023 – 0.045 (0.584 – 1.143) HALF LEAD OPTION 16 15 14 13 12 11 10 9 0.220 – 0.310 (5.588 – 7.874) 0.025 (0.635) RAD TYP 0.045 – 0.068 (1.143 – 1.727) FULL LEAD OPTION 2 1 3 5 4 6 7 8 0.200 (5.080) MAX 0.300 BSC (0.762 BSC) 0.015 – 0.060 (0.380 – 1.520) 0.008 – 0.018 (0.203 – 0.
PAGE 9
LT1180A/LT1181A U PACKAGE DESCRIPTIO N Package 16-Lead PDIP (Narrow .300 Inch) (Reference LTC DWG # 05-08-1510) 0.770* (19.558) MAX 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8 0.255 ± 0.015* (6.477 ± 0.381) 0.130 ± 0.005 (3.302 ± 0.127) 0.300 – 0.325 (7.620 – 8.255) 0.020 (0.508) MIN 0.009 – 0.015 (0.229 – 0.381) ( +0.035 0.325 –0.015 8.255 +0.889 –0.381 0.045 – 0.065 (1.143 – 1.651) ) 0.065 (1.651) TYP 0.125 (3.175) MIN 0.018 ± 0.003 (0.457 ± 0.076) 0.100 (2.
PAGE 10
LT1180A/LT1181A U PACKAGE DESCRIPTIO SW Package 16-Lead Plastic Small Outline (Wide .300 Inch) (Reference LTC DWG # 05-08-1620) 0.398 – 0.413* (10.109 – 10.490) 16 15 14 13 12 11 10 9 0.394 – 0.419 (10.007 – 10.643) NOTE 1 1 0.291 – 0.299** (7.391 – 7.595) 2 3 4 5 6 7 0.093 – 0.104 (2.362 – 2.642) 0.010 – 0.029 × 45° (0.254 – 0.737) 8 0.037 – 0.045 (0.940 – 1.143) 0° – 8° TYP 0.009 – 0.013 (0.229 – 0.330) NOTE 1 0.016 – 0.050 (0.406 – 1.270) 0.050 (1.270) BSC 0.004 – 0.012 (0.
PAGE 11
LT1180A/LT1181A U PACKAGE DESCRIPTIO SW Package 18-Lead Plastic Small Outline (Wide .300 Inch) (Reference LTC DWG # 05-08-1620) 0.447 – 0.463* (11.354 – 11.760) 18 17 16 15 14 13 12 11 10 0.394 – 0.419 (10.007 – 10.643) NOTE 1 0.291 – 0.299** (7.391 – 7.595) 1 2 3 4 5 6 7 8 9 0.093 – 0.104 (2.362 – 2.642) 0.010 – 0.029 × 45° (0.254 – 0.737) 0.037 – 0.045 (0.940 – 1.143) 0° – 8° TYP 0.009 – 0.013 (0.229 – 0.330) NOTE 1 0.016 – 0.050 (0.406 – 1.270) 0.050 (1.270) BSC 0.004 – 0.
PAGE 12
LT1180A/LT1181A UO TYPICAL APPLICATI Operation Using 5V and 12V Power Supplies 12V INPUT 2 17 4 3 5V INPUT LT1180A + 0.1µF LOGIC INPUTS 5 7 –12VOUT + 6 12 15 11 8 13 14 0.