MAX2605/MAX2606/MAX2608/MAX2609 VCO Phase Noise Measurements

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Abstract

Phase noise performance is measured and presented for Analog's IF voltage-controlled oscillators (VCOs). The phase noise of the VCOs tested rolled-off at 20dB/decade between 10kHz and 1MHz offset. All measurements were taken with Analog Devices Evaluation kits. VCC = +2.75V, TA = +25°C, and VTUNE = 1.4V.

The MAX2605-MAX2609 are compact, high-performance intermediate-frequency (IF) voltage-controlled-oscillators (VCOs) designed specifically for demanding portable wireless communication systems. They combine monolithic construction with low-noise, low-power operation in a tiny 6-pin SOT23 package. These low-noise VCOs feature an on-chip varactor and feedback capacitors that eliminate the need for external tuning elements, making the MAX2605-MAX2609 ideal for portable systems.

This application note describes phase-noise measurements performed on these parts, using Analog Devices Evaluation kits. VCC = +2.75V, TA = +25°C, and VTUNE = 1.4V.

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Note that in each graph presented, the phase noise follows the expect 20dB per decade roll-off. The MAX2607 was not measured for this application note, so a graph was not prepared. Expect the phase noise of the MAX2607 to follow the same roll-off exhibited by all the VCOs in this family.