LMX2541 Ultra-Low Noise PLLatinum Frequency Synthesizer with Integrated VCO | TI.com


Ultra-Low Noise PLLatinum Frequency Synthesizer with Integrated VCO

Ultra-Low Noise PLLatinum Frequency Synthesizer with Integrated VCO - LMX2541


The LMX2541 is an ultra low-noise frequency synthesizer which integrates a high performance delta-sigma fractional N PLL, a VCO with fully integrated tank circuit, and an optional frequency divider. The PLL offers an unprecedented normalized noise floor of -225 dBc/Hz and can be operated with up to 104 MHz of phase-detector rate (comparison frequency) in both integer and fractional modes. The PLL can also be configured to work with an external VCO.

The LMX2541 integrates several low-noise, high precision LDOs and output driver matching network to provide higher supply noise immunity and more consistent performance, while reducing the number of external components. When combined with a high quality reference oscillator, the LMX2541 generates a very stable, ultra low-noise signal.

The LMX2541 is offered in a family of 6 devices with varying VCO frequency range from 1990 MHz up to 4 GHz. Using a flexible divider, the LMX2541 can generate frequencies as low as 31.6 MHz.

The LMX2541 is a monolithic integrated circuit, fabricated in a proprietary BiCMOS process. Device programming is facilitated using a three-wire MICROWIRE interface that can operate down to 1.6 volts. Supply voltage ranges from 3.15 V to 3.45 V. The LMX2541 is available in a 36-pin 6-mm × 6-mm × 0.8-mm WQFN Package.


  • Multiple Frequency Options Available
    (See Device Comparison Table)
  • Frequencies from 31.6 MHz to 4000 MHz
  • Very Low RMS Noise and Spurs
  • –225 dBc/Hz Normalized PLL Phase Noise
  • Integrated RMS Noise (100 Hz – 20 MHz)
    • 2 mRad (100 Hz – 20 MHz) at 2.1 GHz
    • 3.5 mRad (100 Hz - 20 MHz) at 3.5 GHz
  • Ultra Low-Noise Integrated VCO
  • External VCO Option (Internal VCO Bypassed)
  • VCO Frequency Divider 1 to 63 (all values)
  • Programmable Output Power
  • Up to 104-MHz Phase Detector Frequency
  • Integrated Low-Noise LDOs
  • Programmable Charge Pump Output
  • Partially Integrated Loop Filter
  • Digital Frequency Shift Keying (FSK) Modulation Pin
  • Integrated Reference Crystal Oscillator Circuit
  • Hardware and Software Power Down
  • FastLock Mode and VCO-Based Cycle Slip Reduction
  • Analog and Digital Lock Detect
  • 1.6-V Logic Compatibility

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Parametrics Compare all products in RF PLLs and Synthesizers

Output Frequency (Min) (MHz)
Output Frequency (Max) (MHz)
Normalized PLL Phase Noise (dBc/Hz)
1/f Noise (10 kHz offset at 1 GHz carrier) (dBc/Hz)
Current Consumption (mA)
Integrated VCO
3.15 to 3.45    

Featured tools and software

WEBENCH® Designer LMX2541

Recommend Input Frequency Tunable Output Frequency
Input Frequency Min Output Frequency
 MHz  MHz
Max Output Frequency
Channel Spacing