Product details

Integrated VCO Yes Output frequency (min) (MHz) 50 Output frequency (max) (MHz) 3800 Normalized PLL phase noise (dBc/Hz) -229 Current consumption (mA) 178 Features Integrated VCO, Wideband 1/f noise (10-kHz offset at 1-GHz carrier) (dBc/Hz) -125 Rating Catalog Operating temperature range (°C) -40 to 85 Lock time (µs) (typ) 10
Integrated VCO Yes Output frequency (min) (MHz) 50 Output frequency (max) (MHz) 3800 Normalized PLL phase noise (dBc/Hz) -229 Current consumption (mA) 178 Features Integrated VCO, Wideband 1/f noise (10-kHz offset at 1-GHz carrier) (dBc/Hz) -125 Rating Catalog Operating temperature range (°C) -40 to 85 Lock time (µs) (typ) 10
WQFN (RTV) 32 25 mm² 5 x 5
  • Output Frequency from 50 to 3800 MHz
  • Input Clock Frequency up to 900 MHz
  • Phase Detector Frequency up to 200 MHz
  • Supports Fractional and Integer Modes
  • –229 dBc/Hz Normalized PLL Phase Noise
  • –120.8 dBc/Hz Normalized PLL 1/f Noise
  • –137 dBc/Hz VCO Phase Noise at 1 MHz offset
    for a 2.5 GHz Carrier
  • 100 fs RMS Jitter in Integer Mode
  • Programmable Fractional ModulatorOrder
  • Programmable Fractional Denominator
  • Programmable Output Power up to 12 dBm
  • Programmable 32 Level Charge Pump Current
  • Programmable Option to Use an External VCO
  • Digital Lock Detect
  • 3-Wire Serial Interface and Readback
  • Single Supply Voltage from 3.15 V to 3.45 V
  • Supports Logic Levels down to 1.6 V
  • Output Frequency from 50 to 3800 MHz
  • Input Clock Frequency up to 900 MHz
  • Phase Detector Frequency up to 200 MHz
  • Supports Fractional and Integer Modes
  • –229 dBc/Hz Normalized PLL Phase Noise
  • –120.8 dBc/Hz Normalized PLL 1/f Noise
  • –137 dBc/Hz VCO Phase Noise at 1 MHz offset
    for a 2.5 GHz Carrier
  • 100 fs RMS Jitter in Integer Mode
  • Programmable Fractional ModulatorOrder
  • Programmable Fractional Denominator
  • Programmable Output Power up to 12 dBm
  • Programmable 32 Level Charge Pump Current
  • Programmable Option to Use an External VCO
  • Digital Lock Detect
  • 3-Wire Serial Interface and Readback
  • Single Supply Voltage from 3.15 V to 3.45 V
  • Supports Logic Levels down to 1.6 V

The LMX2581E is a low-noise wideband frequency synthesizer that integrates a delta-sigma fractional N PLL, multiple core VCO, programmable output divider, and two differential output buffers. The VCO frequency range is from 1880 to 3800 MHz and can be sent directly to the output buffers or divided down by even values from 2 to 38. Each buffer is capable of output power from –3 to +12 dBm at 2700 MHz. Integrated low-noise LDOs are used for superior noise immunity and consistent performance.

This synthesizer is a highly programmable device and it enables the user to optimize its performance. In fractional mode, the denominator and the modulator order are programmable and can be configured with dithering as well. The user also has the ability to directly specify a VCO core or entirely bypass the internal VCO. Finally, many convenient features are included such as power down, Fastlock, auto mute, and lock detection. All registers can be programmed through a simple 3-wire interface and a read back feature is also available.

The LMX2581E operates on a single 3.3 V supply and comes in a 32 pin 5.0 mm × 5.0 mm WQFN package.

The LMX2581E is a low-noise wideband frequency synthesizer that integrates a delta-sigma fractional N PLL, multiple core VCO, programmable output divider, and two differential output buffers. The VCO frequency range is from 1880 to 3800 MHz and can be sent directly to the output buffers or divided down by even values from 2 to 38. Each buffer is capable of output power from –3 to +12 dBm at 2700 MHz. Integrated low-noise LDOs are used for superior noise immunity and consistent performance.

This synthesizer is a highly programmable device and it enables the user to optimize its performance. In fractional mode, the denominator and the modulator order are programmable and can be configured with dithering as well. The user also has the ability to directly specify a VCO core or entirely bypass the internal VCO. Finally, many convenient features are included such as power down, Fastlock, auto mute, and lock detection. All registers can be programmed through a simple 3-wire interface and a read back feature is also available.

The LMX2581E operates on a single 3.3 V supply and comes in a 32 pin 5.0 mm × 5.0 mm WQFN package.

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Technical documentation

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* Data sheet LMX2581E Wideband Frequency Synthesizer with Integrated VCO datasheet PDF | HTML 27 Jul 2015
EVM User's guide LMX2581EVM User's Guide (Rev. C) 25 Nov 2013

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

LMX2581EVM — LMX2581 evaluation module

The LMX2581 Wideband frequency synthesizer allows the generation of a broad range of frequencies with excellent phase noise. The LMX2581 Reference Board (LMX2581EVM) is designed to assist in the evaluation of the LMX2581 in a system, as well as serve as a reference design for the customer’s (...)

User guide: PDF
Not available on TI.com
Evaluation board

TSW16DX370EVM — TSW16DX370EVM Evaluation Module

The TSW16DX370EVM is a reference design board used to evaluate the high performance receiver IF super-heterodyne subsystem solution including the following products from Texas Instruments:

  • TRF37B32 dual down-converting mixer with integrated IF amplifier
  • LMH6521 dual digitally controlled variable gain (...)
User guide: PDF
Not available on TI.com
Application software & framework

PLLATINUMSIM-SW — Texas Instruments PLLatinum Simulator Tool

PLLATINUMSIM-SW is a simulation tool that allows users to create detailed designs and simulations of our PLLatinum™ integrated circuits, which include the LMX series of phase-locked loops (PLLs) and synthesizers.
Application software & framework

TICSPRO-SW — Texas Instruments Clocks and Synthesizers (TICS) Pro Software

Texas Instruments clocks and synthesizers (TICS) pro software is used to program the evaluation modules (EVMs) for product numbers with these prefixes: CDC, LMK and LMX. These products include phase-locked loops and voltage-controlled oscillators (PLL+VCO), synthesizers and clocking devices.
Simulation model

LMX2581 IBIS Model

SNAM157.ZIP (54 KB) - IBIS Model
Design tool

CLOCK-TREE-ARCHITECT — Clock tree architect programming software

Clock tree architect is a clock tree synthesis tool that streamlines your design process by generating clock tree solutions based on your system requirements. The tool pulls data from an extensive database of clocking products to generate a system-level multi-chip clocking solution.
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