Texas Instruments' LMX2581 is an ultra low-noise, wideband frequency synthesizer which integrates a delta-sigma fractional N PLL, a VCO with fully integrated tank circuit, and an optional frequency divider. The LMX2581 integrates several low-noise, high-precision LDOs to provide superior supply noise immunity and more consistent performance. When combined with a high-quality reference oscillator, the LMX2581 generates a very stable, ultra-low noise signal. The internal VCO can be bypassed so that an external VCO can be used.