LMX5080

Prescaler for RF Personal Communications

General Description

The LMX5080 integrated dual modulus prescaler, is de-

signed to be used in a synthesized local oscillator for

2.5 GHz wireless transceivers. It is fabricated using Nation-

al’s 0.5µ ABiCV silicon BiCMOS process. The LMX5080 con-

tains three dual modulus prescalers. Either a 128/130,

256/158 or a 512/514 prescaler can be selected for up to

2.7 Gz RF input frequencies. The prescaler inputs can be

driven either differentially, or single ended with the use of a

coupling capacitor on one of the inputs to ground. The

LMX5080 CMOS output is optimized to generate very stable,

low switching noise output signals. The LMX5080 prescaler

can be used in conjunction with a low frequency Phase Lock

Loop to form a frequency synthesizer suitable for UHF trans-

ceivers. Supply voltage can range from 2.7V to 5.5V. The

LMX5080 features low current consumption; typically 7.0 mA

at 5V V

CC

The LMX5080 is available in a 8-pin Small Outline (SOP)

surface mount plastic package.

Features

n 2.7V to 5.5V operation

n −40˚C to +85˚C low noise CMOS output

n Selectable dual modulus prescaler

128/130

256/258

512/514

n 8-pin small package outline (SOP)

Applications

n 2.5 GHz wireless communications systems (ISM)

n Direct Broadcast Satellite systems (DBS)

n Cable TV tuners (CATV)

Functional Block Diagram

DS100940-1

PRELIMINARY

April 1999

© 1999 National Semiconductor Corporation

DS100940

www.national.com