SPD1101-111

Preliminary Sampling Phase Detectors SPD1101-111, SPD1102-111, SPD1103-111 Features I For Phase Locked VCOs to 22 GHz I Reference Frequencies Below 50 MHz I New Surface Mount Package Design I Small Footprint (90 x 110 Mils) I Automated Chip on Board Construction Description Alpha has redesigned its product line of sampling phase detectors using automated chip on board manufacturing technology to provide a more uniform, surface mountable, small footprint device without sacrificing the microwave performance of the original design. Sampling phase detectors are used to phase lock a microwave VCO to a stable reference source at a submultiple frequency. The sampling phase detector consists of a step recovery diode, capacitors and a microwave mixer consisting of series pair Schottky diodes. The principle of operation may be described as using the step recovery diode to generate a harmonic comb of the reference oscillator frequency and the Schottky diode as a mixer between the closest reference frequency multiple and the microwave signal generated by the VCO. When these frequencies are identical the IF (beat note) signal is a DC voltage; the IF will be sinusoidal when the frequencies are unequal. The SPD1100 series sampling phase detectors use a selected step recovery diode chip whose carrier lifetime and transition time are appropriate for use in applications allowing reference frequencies below 50 MHz and microwave VCO frequencies as high as 22 GHz. The Schottky diodes used are ...