VddRF5

Phase

Comp

FinIF

Charge

Pump

CPoutIF

Ftest/LD

MUX

Ftest/LD

IF

LD

Phase

Comp

8/9

or

16/17

Prescaler

B Counter

IF N Divider

A Counter

FLoutRF

VddIF2

VddIF1

RF N Divider

GND

GND

GND

FinRF

FinRF*

16/17/20/21

or

32/33/36/37

Prescaler

C Counter

6'

Compensation

A Counter

B Counter

RF N Divider

ENOSC

OSCout

OSCin

VddRF4

VddRF3

VddRF2

VddRF1

IF R

Divider

RF R

Divider

1X / 2X

RF LD

Charge

Pump

CPoutRF

RF Fastlock

MICROWIRE

Interface

CLK

LE

DATA

CE

Product

Folder

Sample &

Buy

Technical

Documents

Tools &

Software

Support &

Community

LMX2486

SNAS324B – JANUARY 2006 – REVISED JANUARY 2016

LMX2486 1-GHz to 4.5-GHz High-Performance Delta-Sigma Low-Power Dual PLLatinum™

Frequency Synthesizers With 3-GHz Integer PLL

1

1 Features

•

Quadruple Modulus Prescaler for Lower Divids

3 Description

The

LMX2486

device

is

a

low-power,

high

–

RF PLL: 16/17/20/21 or 32/33/36/37

performance delta-sigma fractional-N PLL with an

–

IF PLL: 8/9 or 16/17

auxiliary integer-N PLL. The device is fabricated

•

Advanced Delta Sigma Fractional Compensation

using TI’s advanced process.

–

12-Bit or 22-Bit Selectable Fractional Modulus

With delta-sigma architecture, fractional spurs at

–

Up to 4th Order Programmable Delta-Sigma

lower

offset

frequencies

are

pushed

to

higher

Modulator

frequencies outside the loop bandwidth. The ability to

push close in spur and phase noise energy to higher

•

Improved Lock Times and Programming

frequencies is a direct function of the modulator

–

Fastlock / Cycle Slip Reduction Which

order.

Unlike

analog

compensation,

the

digital

Requires Only a Single-Word Write

feedback technique used in the LMX2486 is highly

–

Integrated Time-Out Counter

resistant to changes in temperature and variations in

wafer

processing.

The

LMX2486

delta-sigma

•

Wide Operating Range

modulator is programmable up to fourth order, which

–

LMX2486 RF PLL: 1.0 GHz to 4.5 GHz

allows the designer to select the optimum modulator

•

Useful Features

order to fit the phase noise, spur, and lock time

requirements of the system.

–

Digital Lock Detect Output

–

Hardware and Software Power-Down Control

Serial

data

for

programming

the

LMX2486

is

transferred through a three-line, high-speed (20-MHz)

–

On-Chip Crystal Reference Frequency Doubler

MICROWIRE interface. The LMX2486 offers fine

–

RF Phase Detector Frequency Up to 50 MHz

frequency resolution, low spurs, fast programming

–

speed, and a single-word write to change the

frequency. This makes it ideal for direct digital

2 Applications

modulation applications, where the N-counter is

directly modulated with information. The LMX2486 is

•

Cellular Phones and Base Stations

available in a 24-lead 4.0 × 4.0 × 0.8 mm WQFN

•

Direct Digital Modulation Applications

package.

•

Satellite and Cable TV Tuners

Device Information(1)

•

WLAN Standards

PART NUMBER

PACKAGE

BODY SIZE (NOM)

LMX2486

WQFN (24)

4.00 mm × 4.00 mm

(1) For all available packages, see the orderable addendum at

the end of the data sheet.

Functional Block Diagram

1

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.