850MHz to 1550MHz SiGe Mixer Delivers Unparalleled Spurious Intermodulation Rejection

When configured as a downconverter, this single IC provides 35dBm of IIP3, 24dBm of IP1dB, 7.4dB of conversion loss, and a 7.8dB noise figure. In addition, it exhibits outstanding levels of 2 x 1, 2 x 2, and 3 x 3 spurious suppression, with typical values of 88dBc, 79dBc, and 101dBc (with a -14dBm input level), respectively, over the entire 50MHz to 1000MHz IF band. Its high linearity and excellent spurious suppression are critical for ensuring DOCSIS-compliant transmission into the 50MHz to 1000MHz spectrum in cable head-end systems.

As an upconverter, the MAX2051 delivers equally impressive performance with 33.4dBm of IIP3, a low conversion loss of only 7.5dB, and better than 61dBc of LO ±2IF and 78dBc of LO ±3IF suppression. This device is ideal for all point-to-point and point-to-multipoint microwave and fixed broadband wireless-access base-station applications, which require first IF to second IF upconversion stages covering the 850MHz to 1550MHz band.

Maxim's proprietary SiGe process enables the MAX2051 to integrate a state-of-the-art, double-balanced mixer core with an LO amplifier, two baluns, plus dozens of discrete components-all into one monolithic device. When compared to the closest competing solution, the MAX2051 reduces the total board space by 72%, and reduces the discrete part count by 25%. The device's outstanding spurious performance also eases the filtering requirements of close-in harmonics, thus enabling simpler, smaller, and more cost-effective filter designs.

To complement the mixer's exceptionally wide IF range, the MAX2051 includes a similarly wide-range LO buffer circuit that is optimized for high-side LO injection architectures covering the 1200MHz to 2250MHz frequency spectrum. The on-board 0dBm drive LO buffer provides ±3dB drive-variance control, thus ensuring stable gain, NF, and IIP3 performance over temperature, supply, and input power. The MAX2051 also has excellent gain-variation performance of 0.01dB/degree Celsius over the -40 degrees Celsius to +85 degrees Celsius industrial temperature range.