LTC491

10

491fa

S

APPLICATI

I FOR ATIO

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, some applications need more

protection. The best protection method is to connect a

bidirectional TransZorb

(Figure 16).

A TransZorb is a silicon transient voltage suppressor that

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

Figure 16. ESD Protection with TransZorbs

LTC491 • F16

120

Ω

DRIVER

Z

Y

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

forget to check how much the added parasitic capacitance

will load down the bus.

TransZorb is a registered trademark of General Instruments, GSI

PACKAGE DESCRIPTIO

N Package

14-Lead PDIP (Narrow .300 Inch)

(Reference LTC DWG # 05-08-1510)

N14 1002

.020

(0.508)

MIN

.120

(3.048)

MIN

.130

± .005

(3.302

± 0.127)

.045 – .065

(1.143 – 1.651)

.065

(1.651)

TYP

.018

± .003

(0.457

± 0.076)

.005

(0.125)

MIN

.255

± .015*

(6.477

± 0.381)

.770*

(19.558)

MAX

3

1

2

4

5

6

7

8

9

10

11

12

13

14

.008 – .015

(0.203 – 0.381)

.300 – .325

(7.620 – 8.255)

.325

+.035

–.015

+0.889

–0.381

8.255

()

NOTE:

1. DIMENSIONS ARE

INCHES

MILLIMETERS

*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.

MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)

.100

(2.54)

BSC