The HMC700LP4E is a SiGe BiCMOS fractional-N Frequency Synthesizer includes a very low noise digital phase frequency detector (PFD) and a precision controlled charge pump. The fractional synthesizer features an advanced delta-sigma modulator design that allows both ultra-fine step sizes and very low spurious products. Spurious outputs are low enough to eliminate the need for costly Direct Digital Synthesis (DDS) references in many applications. The HMC700LP4(E) phase-frequency detector (PFD) features cycle slip prevention (CSP) technology that allows faster frequency hopping times. Ultra low in-close phase noise and low spurious also permit architectures with wider loop bandwidths for faster frequency hopping and low micro-phonics. FSK mode allows the synthesizer to be used as a simple low cost direct FM transmitter source.