8283

8283 PRELIMINARY INFORMATION (Subject to change without notice) November 21, 2000 LNB SUPPLY AND CONTROL-VOLTAGE REGULATOR Intended for analog and digital satellite receivers, the low-noise block converter regulator (LNBR) is a monolithic linear and switching voltage regulator designed to provide power and interface signals to the LNB down converter via the coaxial cable. If the device is in stand-by mode (EN terminal LOW), the regulator output is disabled, allowing the antenna downconverters to be supplied or controlled by other satellite receivers sharing the same coaxial cable. Similar two-output LNB supply and control voltage regulators are the A8284SB/SLB. For slave operation in single-dish dual-receiver systems, the bypass function is implemented by an electronic switch between the master input terminal (MI) and the LNB terminal, leaving all LNB power and control functions to the master receiver. This electronic switch is closed if the device is powered, EN is HIGH, and OSEL is LOW. The regulator outputs are set to 12, 13, 18, or 20 V by the VSEL terminals. Additionally, it is possible to increase the selected voltage by 1 V to compensate for the voltage drop in the coaxial cable (LLC terminal HIGH). The LNBR combines a tracking switching regulator and low-noise linear regulator. Logic inputs (VSEL0, VSEL1, and LLC) select the desired output voltage. A tracking current-mode buck converter provides the linear regulator with an input voltage that is set to the output vol...