The LMX2531 is a low power, high performance frequency synthesizer system which includes a fully integrated deltasigma PLL and VCO with fully integrated tank circuit. The third and fourth poles are also integrated and also adjustable. Also included are integrated ultra-low noise and high precision LDOs for the PLL and VCO which give higher supply noise immunity and also more consistent performance. When combined with a high quality reference oscillator, the LMX2531 generates very stable, low noise local oscillator signals for up and down conversion in wireless communication devices. The LMX2531 is a monolithic integrated circuit, fabricated in an advanced BiCMOS process. There are several different versions of this product in order to accommodate different frequency bands.