SiGe Mixers for DCS/PCS, WCDMA, WCS, LTE, WiMAX, and MMDS Base Stations
Maxim has introduced the MAX19995/MAX19995A/MAX19997A/MAX19999 family of high-performance, dual, downconverting mixers targeted specifically for DCS/PCS, cdma2000, WCDMA, WCS, LTE, WiMAX (TM), and MMDS wireless-infrastructure applications. Together with the previously announced MAX19985A, these mixers provide complete downconverter solutions that address all base-station applications spanning the 700MHz to 4000MHz bands.Designed using Maxim's proprietary SiGe process, each monolithic device delivers an unparalleled combination of linearity, noise performance, and component integration. As shown in the Performance and Applications table, these components provide up to 24.8dBm IIP3 linearity, up to 9dB of conversion gain, and an unparalleled 2RF-2LO spurious rejection of up to 79dBc. Noise figure values are also exceptionally low, with values reaching down to 9dB. Each of these parameters is critical for providing enhanced receiver sensitivity and blocker immunity.
As complete SiGe downconverters, the MAX19995/MAX19995A/MAX19997A/MAX19999 integrate two state-of-the-art mixer cores, four amplifiers, three baluns, an LO splitter, and dozens of discrete components. The devices' conversion gain enables the elimination of a complete IF amplifier stage within the receiver lineup. The outstanding 2RF-2LO and 2LO-2RF performance can also ease the filtering requirements of close-in harmonics, thus leading to simpler and more cost-effective filter designs. Through this combination of integration and performance, these devices reduce downconverter solution size by a factor of 2x, and discrete part count by 45%.
The entire MAX19985A/MAX19995/MAX19997A/MAX19999 family also supports two unique 'green' power modes in which linearity performance can be traded off for reduced power consumption. In 5V mode, the bias currents that drive the on-chip LO buffer and IF amplifier stages can be reduced by as much as 33%. Using this mode of operation, a 20% reduction in power results in only a 3dB reduction in IIP3 linearity. Similarly, using the 3.3V mode of operation leads to power reductions on the order of 53%, with only a 4dB to 5dB reduction in linearity. Both modes allow the designer to optimize the power consumption of the downconverter for a variety of performance scenarios.
Each device is packaged in a compact, 6mm x 6mm, 36-pin TQFN that is pin similar to the existing MAX9985, MAX19985A, and MAX9995 series of 700MHz to 2200MHz dual mixers. The entire family of dual downconverters is ideal for applications in which a common PCB layout is used for multiple frequency bands.
15th October 2020
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