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LMX2485Q-Q1

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500MHz to 3GHz automotive delta-sigma low power dual PLL

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Data sheet

LMX2485Q-Q1

ACTIVE
Data sheet Order now

Product details

Integrated VCO No Output frequency (min) (MHz) 500 Output frequency (max) (MHz) 3100 Normalized PLL phase noise (dBc/Hz) -210 Current consumption (mA) 5 Features AEC-Q100 Grade 2 qualified, Advanced delta-sigma fractional compensation, Cycle slip reduction, Dual PLL, Fastlock, Integrated timeout counter, On-chip input frequency doubler 1/f noise (10-kHz offset at 1-GHz carrier) (dBc/Hz) -104 Rating Automotive Operating temperature range (°C) -40 to 105 Lock time (µs) (typ) Loop BW dependent
Integrated VCO No Output frequency (min) (MHz) 500 Output frequency (max) (MHz) 3100 Normalized PLL phase noise (dBc/Hz) -210 Current consumption (mA) 5 Features AEC-Q100 Grade 2 qualified, Advanced delta-sigma fractional compensation, Cycle slip reduction, Dual PLL, Fastlock, Integrated timeout counter, On-chip input frequency doubler 1/f noise (10-kHz offset at 1-GHz carrier) (dBc/Hz) -104 Rating Automotive Operating temperature range (°C) -40 to 105 Lock time (µs) (typ) Loop BW dependent
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
  • Improved Lock Times and Programming
    • Fastlock / Cycle Slip Reduction Requiring Only
      a Single-Word Write
    • Integrated Time-Out Counter
  • Wide Operating Range
    • LMX2485Q-Q1 RF PLL: 500 MHz to 3.1 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-V to 3.6-V Operation With ICC = 5.0 mA
    • LMX2485Q-Q1 is AEC-Q100 Grade 2
      Qualified and is Manufactured on an
      Automotive Grade Flow
  • 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
  • Improved Lock Times and Programming
    • Fastlock / Cycle Slip Reduction Requiring Only
      a Single-Word Write
    • Integrated Time-Out Counter
  • Wide Operating Range
    • LMX2485Q-Q1 RF PLL: 500 MHz to 3.1 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-V to 3.6-V Operation With ICC = 5.0 mA
    • LMX2485Q-Q1 is AEC-Q100 Grade 2
      Qualified and is Manufactured on an
      Automotive Grade Flow

The LMX2485Q-Q1 is a low power, high performance delta-sigma fractional-N PLL with an auxiliary integer-N PLL. The device is fabricated using TI’s 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 LMX2485Q-Q1 is highly resistant to changes in temperature and variations in wafer processing. The LMX2485Q-Q1 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 LMX2485Q-Q1 is transferred through a three-line, high-speed (20-MHz) MICROWIRE interface. The LMX2485Q-Q1 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 LMX2485Q-Q1 is available in a 24-lead 4.0 × 4.0 × 0.8 mm WQFN package.

The LMX2485Q-Q1 is a low power, high performance delta-sigma fractional-N PLL with an auxiliary integer-N PLL. The device is fabricated using TI’s 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 LMX2485Q-Q1 is highly resistant to changes in temperature and variations in wafer processing. The LMX2485Q-Q1 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 LMX2485Q-Q1 is transferred through a three-line, high-speed (20-MHz) MICROWIRE interface. The LMX2485Q-Q1 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 LMX2485Q-Q1 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 LMX2485Q-Q1 500 MHz - 3.1 GHz High Performance Delta-Sigma Low Power Dual PLLatinum Frequency Synthesizers With 800-MHz Integer PLL datasheet (Rev. A) PDF | HTML 13 Jan 2016
Application note AN-1879 Fractional N Frequency Synthesis (Rev. B) 18 Nov 2021
EVM User's guide LMX248x Evaluation Board User's Guide (Rev. B) 27 Jul 2018

Design & development

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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.
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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.
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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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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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