Low noise fractional N PLL with ramp/chirp generation uses single 3.3V supply

The LMX2491 device, from Texas Instruments, is a low-noise, 6.4GHz wideband delta-sigma fractional N PLL with ramp and chirp generation. It consists of a phase frequency detector, programmable charge pump, and high frequency input for the external VCO. The device supports a broad and flexible class of ramping capabilities, including FSK, PSK, and configurable piecewise linear FM modulation profiles of up to eight segments. It supports fine PLL resolution and fast ramp with up to a 200MHz phase detector rate. The device allows any of its registers to be read back. It can operate with a single 3.3V supply. Moreover, supporting up to 5.25V charge pump can eliminate the need of external amplifier, leading to a simpler solution with improved phase noise performance.