LNB voltage regulator ICs for satellite receivers

These low-noise block convertor regulators are monolithic linear/switching voltage regulators, specifically designed to provide the power and interface signals to an LNB down-convertor via a coaxial cable. The integrated boost switch in each device has been optimised to minimise both switching and
static losses. To further enhance efficiency, the voltage drop across the tracking regulator has also been minimised.

The A8290 (single) and A8286 (dual) devices provide the higher output current required by the latest satellite set-top box applications. The A8286 provides up to 650 mA per channel and 1.0 A total continuous lead current, while the corresponding figures for the A8290 are 500 mA and 750 mA. The
A8291 (single) and A8292 (dual) versions have lower current limits for more traditional requirements.

All four devices offer 'push/pull' output stages with the ability to sink and source current, and a static current limit with overcurrent timer mode. They also offer a 'cable disconnect' function in addition to a wide variety of other diagnostic capabilities.

The regulator ICs require few external components because the boost switch, compensation circuitry, and sense resistor are all integrated into the solution. The A8290 and A8291 also integrate an output filter bypass FET. A high switching frequency is chosen to minimise the size of the passive
filtering components to further assist in reducing cost.

All four devices are available in the 5 x 5 mm QFN/MLP-28 package.