1

FEATURES

PIN ASSIGNMENT

APPLICATIONS

1

8

2

7

3

6

4

5

NC

Q

NC

V

CC

D

D

GND

V

BB

DESCRIPTION

SN65ELT21

www.ti.com....................................................................................................................................................................................................... SLLS923 – JUNE 2009

5-V PECL-to-TTL Translator

• 3ns (TYP) Propagation Delay

• Operating Range: V

CC = 4.2 V to 5.7 V with

D or DGK PACKAGE

GND = 0 V

(TOP VIEW)

• 24-mA TTL Output

• Deterministic Output Value for Open Input

Conditions or When Inputs < 1.3 V

• Built-In Temperature Compensation

• Drop-In Compatible to the MC10ELT21,

MC100ELT21

• Data and Clock Transmission Over Backplane

• Signaling Level Conversion for Clock or Data

Table 1. Pin Descriptions

The

SN65ELT21

is

a

differential

PECL-to-TTL

translator. It operates on +5-V supply and ground

PIN

FUNCTION

only. The device includes circuitry to maintain Q to a

D, D

PECL data inputs

low logic level when inputs are in an open condition

Q

TTL output

or < 1.3 V.

VCC

Positive supply

The VBB pin is a reference voltage output for the

VEE

Negative supply

device. When the device is used in single-ended

VBB

Reference voltage output

mode, the unused input should be tied to VBB. This

reference voltage can also be used to bias the input

when it is ac coupled. When it is used, place a

0.01

µF decoupling capacitor between V

CC and VBB.

Also limit the sink/source current to < 0.5 mA to VBB.

Leave VBB open when it is not used.

The SN65ELT21 is housed in an industry standard

SOIC-8 package and is also available in an optional

TSSOP-8 package.

ORDERING INFORMATION(1)(2)

PART NUMBER

PART MARKING

PACKAGE

LEAD FINISH

SN65ELT21D

ELT21

SOIC

NiPdAu

SN65ELT21DGK

SIII

SOIC-TSSOP

NiPdAu

(1)

For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI

web site at www.ti.com.

(2)

Leaded device options are not initially available; contact a sales representative for further details.

1

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas

Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

PRODUCTION DATA information is current as of publication date.

Copyright © 2009, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.