Integrating all bias, control and power management functions into a single chip, the latest low noise block (LNB) satellite controllers from Zetex Semiconductors help achieve LNB size reductions of up to 30 percent, according to the company. Three LNB controllers have been introduced: The ZXNB4100 (negative volt bias) and ZXNB4200 (zero volt bias) for single universal LNBs with FET switching topologies, and the ZXNB2200 for C-band LNB designs. Offered in 16-pin 3 mm × 3 mm and 4 mm ×4 mm QFN packages, the controllers require just three external components to function. ZXNB controllers provide biasing for up to three GaAS FET LNA stages and an active mixer. To optimize system performance, the drain current of LNA FETs and the active mixer is user selectable, via an external reference resistor. The on-board voltage detector enables the required polarization channel, while a 22 kHz tone detector -- with integrated filter and signal rejection -- handles switching between high and low band oscillators. ZXNB controllers are “self powering,” bringing the voltage regulator into the LNB controller chip for the very first time. They are able to provide a temperature compensated, high current output voltage sufficient to power all parts of the LNB circuit, such as IF amplifier stages. This allows LNB controller to also protect against overload, over-temperature and installation errors. The ZXNB4100 and ZXNB4200 are unit priced at $1.78 at 1,000 quantity (3mm x 3mm QFN package). The ZXNB2200 is unit priced at $1.63 at 1,000 quantity.

Zetex Semiconductors