LMX2541 Datasheet | National Semiconductor

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 normalized noise floor of -225 d Bc/Hz and can be operated with up to 104 MHz of phase-detector rate (parison 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 ponents. When bined 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 Bi CMOS process. Device programming is facilitated using a three-wire MICROWIRE interface that can operate down to 1.8 volts. Supply voltage ranges from 3.15 to 3.45 volts. The LMX2541 is available in a 36 pin 6x6x0.8 mm Lead-Free Leadless Leadframe Package (LLP). Device LMX2541SQ2060E LMX2541SQ2380E LMX2541SQ2690E LMX2541SQ3030E LMX2541SQ3320E LMX2541SQ3740E VCO Frequency 1990 - 2240 2200 - 2530 2490 - 2865 2810 - 3230 3130 - 3600 3480 - 4000 Features - Very Low RMS Noise and Spurs - -225 d Bc/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...