Date: 13/12/2011

High performace PLL chip-set from Hittite microwave

Hittite Microwave has released the PLL chip set which includes HMC983LP5E (DC to 7 GHz Fractional-N Divider and Frequency Sweeper), HMC984LP4E (Digital Phase-Frequency Detector and Charge Pump) targeted at PLL and Frequency Modulated Continuous Wave (FMCW) sweeper applications requiring ultimate performance.

Hittite says the HMC983LP5E integrates the industry's largest programmable 48-bit Delta-Sigma Modulator which allows the combined PLL to achieve unparalleled fractional frequency resolution of 180 nHz. A built-in frequency sweeper enables the combined PLL to generate identical, coherent, FMCW frequency sweeps that can be linear, user-defined, automatic or triggered.

The HMC984LP4E provides an ultra low noise phase detector and charge pump capable of operating at high phase detector frequencies of 125 MHz in fractional mode, and 175 MHz in integer mode as per Hittite. This capability enables the PLL chip set to utilize wider loop bandwidths which result in better phase noise performance, faster PLL locking times, and faster frequency sweeps, adds Hittite. The PLL chip set phase noise Figure of Merit performance is -231 dBc/Hz in integer mode and -227 dBc/Hz in fractional mode.

Hittite suggests although the HMC983LP5E and the HMC984LP4E can be used separately in stand-alone applications, partitioning the PLL building blocks into two distinct devices achieves superb isolation and results in market leading spurious emissions performance exceeding -60 dBc/Hz inside the loop bandwidth. Both the HMC983LP5E and the HMC984LP4E are housed in plastic leadless surface mount packages and provide excellent temperature stability over the -40 °C to 85 °C operating range.

Samples and evaluation PC boards for all SMT packaged products are available from stock and can be ordered via the company's e-commerce site or via direct purchase order. Released data sheets are available on-line at www.hittite.com.