Product details

Integrated VCO No Output frequency (Min) (MHz) 50 Output frequency (Max) (MHz) 3000 Normalized PLL phase noise (dBc/Hz) -210 Current consumption (mA) 3.3 1/f noise (10-kHz offset at 1-GHz carrier) (dBc/Hz) -104
Integrated VCO No Output frequency (Min) (MHz) 50 Output frequency (Max) (MHz) 3000 Normalized PLL phase noise (dBc/Hz) -210 Current consumption (mA) 3.3 1/f noise (10-kHz offset at 1-GHz carrier) (dBc/Hz) -104
WQFN (RTW) 24 16 mm² 4 x 4
  • Quadruple Modulus Prescaler for Lower Divides
    • RF PLL: 8/9/12/13 or 16/17/20/21
    • IF PLL: 8/9 or 16/17
  • Advanced Delta-Sigma Fractional Compensation
    • 12-Bit or 22-Bit Selectable Fractional Modulus
    • Up to 4th Order Programmable Delta-Sigma
      Modulator
  • Features for Improved Lock Time
    • Fastlock / Cycle Slip Reduction With Integrated
      Time-Out Counter Which Requires Only a
      Single-Word Write
  • Wide Operating Range
    • LMX2485 RF PLL: 500 MHz to 3.0 GHz
    • LMX2485E RF PLL: 50 MHz to 3.0 GHz
  • Useful Features
    • Digital Lock Detect Output
    • Hardware and Software Power-Down Control
    • On-Chip Input Frequency Doubler.
    • RF Phase Detector Frequency up to 50 MHz
    • 2.5 to 3.6 V Operation With ICC = 5.0 mA
  • Quadruple Modulus Prescaler for Lower Divides
    • RF PLL: 8/9/12/13 or 16/17/20/21
    • IF PLL: 8/9 or 16/17
  • Advanced Delta-Sigma Fractional Compensation
    • 12-Bit or 22-Bit Selectable Fractional Modulus
    • Up to 4th Order Programmable Delta-Sigma
      Modulator
  • Features for Improved Lock Time
    • Fastlock / Cycle Slip Reduction With Integrated
      Time-Out Counter Which Requires Only a
      Single-Word Write
  • Wide Operating Range
    • LMX2485 RF PLL: 500 MHz to 3.0 GHz
    • LMX2485E RF PLL: 50 MHz to 3.0 GHz
  • Useful Features
    • Digital Lock Detect Output
    • Hardware and Software Power-Down Control
    • On-Chip Input Frequency Doubler.
    • RF Phase Detector Frequency up to 50 MHz
    • 2.5 to 3.6 V Operation With ICC = 5.0 mA

The LMX2485 device is a low power, high performance delta-sigma fractional-N PLL with an auxiliary integer-N PLL. The device is fabricated using Texas Instruments’ advanced process.

With delta-sigma architecture, fractional spurs at lower offset frequencies are pushed to higher frequencies outside the loop bandwidth. The ability to push close in spur and phase noise energy to higher frequencies is a direct function of the modulator order. Unlike analog compensation, the digital feedback technique used in the LMX2485 is highly resistant to changes in temperature and variations in wafer processing. The LMX2485 delta-sigma modulator is programmable up to fourth order, which allows the designer to select the optimum modulator order to fit the phase noise, spur, and lock time requirements of the system.

Serial data for programming the LMX2485 is transferred through a three-line, high-speed (20-MHz) MICROWIRE interface. The LMX2485 offers fine frequency resolution, low spurs, fast programming speed, and a single-word write to change the frequency. This makes it ideal for direct digital modulation applications, where the N-counter is directly modulated with information. The LMX2485 is available in a 24-lead 4.0 × 4.0 × 0.8 mm WQFN package.

The LMX2485 device is a low power, high performance delta-sigma fractional-N PLL with an auxiliary integer-N PLL. The device is fabricated using Texas Instruments’ advanced process.

With delta-sigma architecture, fractional spurs at lower offset frequencies are pushed to higher frequencies outside the loop bandwidth. The ability to push close in spur and phase noise energy to higher frequencies is a direct function of the modulator order. Unlike analog compensation, the digital feedback technique used in the LMX2485 is highly resistant to changes in temperature and variations in wafer processing. The LMX2485 delta-sigma modulator is programmable up to fourth order, which allows the designer to select the optimum modulator order to fit the phase noise, spur, and lock time requirements of the system.

Serial data for programming the LMX2485 is transferred through a three-line, high-speed (20-MHz) MICROWIRE interface. The LMX2485 offers fine frequency resolution, low spurs, fast programming speed, and a single-word write to change the frequency. This makes it ideal for direct digital modulation applications, where the N-counter is directly modulated with information. The LMX2485 is available in a 24-lead 4.0 × 4.0 × 0.8 mm WQFN package.

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Technical documentation

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Type Title Date
* Data sheet LMX2485x 3-GHz Delta-Sigma Low-Power Dual PLLatinum Frequency Synthesizer datasheet (Rev. G) 13 Jan 2016
User guide LMX248x Evaluation Board User's Guide (Rev. B) 27 Jul 2018
Application note AN-1879 Fractional N Frequency Synthesis (Rev. A) 26 Apr 2013

Design & development

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

Application software & framework

CLOCKDESIGNTOOL — Clock Design Tool - Loop Filter & Device Configuration + Simulation

The Clock Design Tool software helps with part selection, loop filter design and simulation of timing device solutions. When you enter desired output frequencies and a reference frequency (optional), the tool provides TI devices to meet the specified requirements, divider values and a recommended (...)
Application software & framework

PLLATINUMSIM-SW — Texas Instruments PLLatinum Simulator Tool

The PLLATINUMSIM-SW simulator tool lets you create detailed designs and simulations of our PLLATINUM™ integrated circuits which include the LMX series of PLLs and synthesizers.
Application software & framework

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

The TICS Pro software is used to program the evaluation modules (EVMs) for device numbers with these prefixes: CDC, LMK and LMX. These devices include PLLs and voltage-controlled oscillators (PLL+VCO), synthesizers and clocking devices.
IDE, configuration, compiler or debugger

CODELOADER — CodeLoader Software for device register programming

The CodeLoader 4 software is used to program the LMX PLLs and LMK timing devices through either the USB or line print terminal (LPT) port of a computer. This software also provides information on how to program the device by showing the bits that are actually sent.


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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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