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

This product has been released to the market and is available for purchase. For some products, newer alternatives may be available.
Ultra-Low Noise PLLatinum Frequency Synthesizer with Integrated VCO



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


Compare all products in RF PLLs & synthesizers Email Download to Excel
Part number Order 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) VCC (V) Integrated VCO
LMX2541 Order now 32     4000     -226     -125     120     3.15 to 3.45     Yes