General Description
●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
●■ Analog and Digital Lock Detect
●■ 1.6 V Logic Compatibility
●Target Applications
●■ Wireless Infrastructure (UMTS, LTE, WiMax)
●■ Broadband Wireless
●■ Wireless Meter Reading
●■ Test and Measurement
