Charge

Pump

Digital

Control

CS#

SCK

SDI

Lock

Detection

×2

OSCIN_P

RFOUTA_P

x3,x4..x7

CE

÷2,4,8,..,128

Phase Sync

G4

Modulator

LD

N Divider

×2

MUTE

÷1,2,..4095

÷1,2,..255

PFD

SYSREF

Generation

÷2

÷2,4,8,..,128

RFOUTA_N

OSCIN_N

SRREQ_P

SRREQ_N

RFOUTB_P

RFOUTB_N

SROUT_P

SROUT_N

MUXOUT

Product

Folder

Order

Now

Technical

Documents

Tools &

Software

Support &

Community

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. ADVANCE INFORMATION for pre-production products; subject to

change without notice.

LMX2820

SNAS783 – JUNE 2020

LMX2820 22.4-GHz Wideband PLLatinum™ RF Synthesizer

With Phase Synchronization and JESD204B Support

1

1 Features

1

•

Output frequency: 43.75 MHz to 22.4 GHz

•

< 40-fs rms jitter (12 kHz – 95 MHz)

•

High-performance PLL

–

Figure of merit: –236 dBc/Hz

–

Normalized 1/f noise: –134 dBc/Hz

–

High phase detector frequency

–

400-MHz integer mode

–

300-MHz fractional mode

–

Programmable input multiplier

–

Direct PFD input for offset mixing support

•

< 5-µs fast VCO calibration time

•

Mute pin with 200-ns mute/unmute time

•

–40-dBc VCO leakage with doubler enabled

•

Support for external VCO up to 22 GHz

•

Synchronization of output phase across multiple

devices

•

Two differential RF outputs and one differential

SYSREF output for JESD204B support

2 Applications

•

Radar and electronic warfare

•

5G and mm-Wave wireless infrastructure

•

Microwave backhaul

•

Test and measurement equipment

•

High-speed data converter clocking

3 Description

The LMX2820 is a high-performance, wideband

synthesizer that can generate any frequency in the

range of 43.75 MHz to 22.4 GHz. The high-

performance PLL with figure of merit of –236 dBc/Hz

and high phase detector frequency can attain very

low in-band noise and integrated jitter. The high-

speed N-divider has no pre-divider, thus significantly

reducing the amplitude and number of spurs. There is

also a programmable input multiplier to mitigate

integer boundary spurs.

The LMX2820 allows users to synchronize the output

of multiple devices and also enables applications that

need deterministic delay between input and output.

The fast calibration algorithm greatly reduces the

VCO calibration time to under 5 µs, enabling systems

requiring fast frequency hopping. The LMX2820 can

generate or repeat SYSREF that is compliant to the

JESD204B standard, allowing for its use as a low-

noise clock source for high-speed data converters.

This synthesizer can also be used with an external

VCO. A direct PFD input pin is provided to support

offset mixing for low spurious transmission.

The device runs from a single 3.3-V supply and has

integrated LDOs that eliminate the need for onboard

low-noise LDOs.

Device Information(1)

PART NUMBER

PACKAGE

BODY SIZE (NOM)

LMX2820

VQFN (48)

7.00 mm × 7.00 mm

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

the end of the data sheet.

Functional Block Diagram