Ultralow Noise and Spurious 0.35GHz to 6GHz Integer-N Synthesizer

The LTC6945 is a high performance, low noise, 6GHz phase-locked loop (PLL), including a reference divider, phase-frequency detector (PFD) with phase-lock indicator, charge pump, integer feedback divider and VCO output divider.

The part features a buffered, programmable VCO output divider with a range of 1 through 6. The differential, low noise output buffer has user-programmable output power ranging from –6dBm to 3dBm, and may be muted through either a digital input pin or software.

The low noise reference buffer outputs a typical 0dBm square wave directly into a 50Ω impedance from 10MHz to 250MHz, or may be disabled through software.

The ultralow noise charge pump contains selectable high and low voltage clamps useful for VCO monitoring, and also may be set to provide a V+/2 bias.

All device settings are controlled through a SPI-compatible serial port.

Applications

* Wireless Base Stations (LTE, WiMAX, W-CDMA, PCS)

* Broadband Wireless Access

* Microwave Data Links

* Military and Secure Radio

* Test and Measurement

* Low Noise Integer-N PLL

* 350MHz to 6GHz VCO Input Range

* –226dBc/Hz Normalized In-Band Phase Noise Floor

* –274dBc/Hz Normalized In-Band 1/f Noise

* –157dBc/Hz Wideband Output Phase Noise Floor

* Excellent Spurious Performance

* Output Divider (1 to 6, 50% Duty Cycle)

* Low Noise Reference Buffer