LTC486

8

S

APPLICATI

I FOR ATIO

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7487

NOTE:

1. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS.

THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS.

NOTE 1

0.398 – 0.413

(10.109 – 10.490)

(NOTE 2)

16

15

14

13

12

11

10

9

1

23

4

5

6

78

0.394 – 0.419

(10.007 – 10.643)

0.037 – 0.045

(0.940 – 1.143)

0.004 – 0.012

(0.102 – 0.305)

0.093 – 0.104

(2.362 – 2.642)

0.050

(1.270)

TYP

0.014 – 0.019

(0.356 – 0.482)

TYP

0° – 8° TYP

NOTE 1

0.005

(0.127)

RAD MIN

0.009 – 0.013

(0.229 – 0.330)

0.016 – 0.050

(0.406 – 1.270)

0.291 – 0.299

(7.391 – 7.595)

(NOTE 2)

× 45°

0.010 – 0.029

(0.254 – 0.737)

2. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.

MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm).

S Package

16-Lead Plastic SOL

LT/GP 0294 5K REV A • PRINTED IN USA

© LINEAR TECHNOLOGY CORPORATION 1994

solution is to use an AC termination with a pull-up resistor.

Simply swap the receiver inputs for data protocols ending

in logic 1.

Fault Protection

All of LTC’s RS485 products are protected against ESD

transients up to

±2kV using the human body model

(100pF, 1.5k

Ω).However,someapplicationsneedgreater

protection. The best protection method is to connect a

bidirectional TransZorb

(Figure 12).

A TransZorb

has exceptional surge handling capabilities, fast response

time, and low series resistance. They are available from

General Semiconductor Industries and come in a variety of

breakdown voltages and prices. Be sure to pick a break-

down voltage higher than the common-mode voltage

required for your application (typically 12V). Also, don’t

forget to check how much the added parasitic capacitance

will load down the bus.

RS232 to RS485 Level Translator with Hysteresis

APPLICATI

TYPICAL

N Package

16-Lead Plastic DIP

0.260 ± 0.010

(6.604 ± 0.254)

0.770

(19.558)

MAX

16

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

0.015

(0.381)

MIN

0.125

(3.175)

MIN

0.130 ± 0.005

(3.302 ± 0.127)

0.065

(1.651)

TYP

0.045 – 0.065

(1.143 – 1.651)

0.018 ± 0.003

(0.457 ± 0.076)

0.045 ± 0.015

(1.143 ± 0.381)

0.100 ± 0.010

(2.540 ± 0.254)

0.009 – 0.015

(0.229 – 0.381)

0.300 – 0.325

(7.620 – 8.255)

0.325

+0.025

–0.015

+0.635

–0.381

8.255

()

PACKAGE DESCRIPTIO

Dimensions in inches (millimeters) unless otherwise noted.

LTC486 • TA14

120

Ω

DRIVER

Y

Z

R = 220k

10k

RS232 IN

5.6k

HYSTERESIS = 10k

×

≈

VY - VZ 

————

R

19k

——

R

1/4 LTC486

LTC486 • TA13

120

Ω

DRIVER

Z

Y

Figure 12. ESD Protection