Downconverting Mixers Bring Exceptional Linearity To Basestation Receivers

Mar 4, 2009 11:43 AM, By Louis E. Frenzel, Editor in Chief

Designed for new cellular and wireless basestations, the MAX19995, MAX19995A, MAX19997A, and MAX19999 mixers from Maxim Integrated Products combine unusually good linearity, noise performance, and component integration that will make designers rethink their newest products. Built using Maxim’s proprietary monolithic silicon-germanium (SiGe) process, they operate from 700 to 4000, suiting almost any wireless infrastructure receiver. Common applications include DCS/PCS, WCDMA, cdma2000, TD-SCDMA, WCS, LTE, WiMAX, and MMDS.

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This line of mixers integrates two mixer cores, four amplifiers, three baluns, an LO splitter, and dozens of discrete components that designers won’t have to add externally. With this much gain on board, it’s possible to eliminate a complete IF amplifier stage in the receiver lineup. The outstanding 2RF-2LO and 2LO-2RF performance can also ease the filtering requirement of close-in harmonics, leading to simpler and more cost-effective filter designs. The overall effect is to reduce downconverter size by a factor of two and discrete parts count by 45%.

Key specifications include up to 24.8-dBm IIP3 linearity, up to 9 dB of conversion gain, and 2RF-2LO spurious rejection of up to 79 dBc. Noise figure values are also exceptionally low, reaching down to 9 dB. These figures add up to enhanced receiver sensitivity and good blocker immunity. The package for these parts is s 6- by 6-mm, 36-pin thin quad flat no-lead (TQFN) that is pin-similar to other similar Maxim mixers, allowing for applications in which a common printed circuit-board (PCB) layout can be used for multiple frequency bands. Prices start at $9.96 in 1000-unit quantities.

Maxim Integrated Products