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 normal ized 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.
Features
■ 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
