I2C bus interface increases control options
STMicroelectronics has introduced a power supply and control IC for the low-noise block circuits used in analog and digital satellite broadcasting TV receivers. The part is designed for use in set-top boxes in all regions and in emerging TV set and PC card applications.
The LNBP21 voltage regulator enlarges a well-established family of power and control ICs for low noise blockers. Unlike previous versions, which used a linear approach, the LNBP21 uses a step-up DC-DC converter so it can work from a single input voltage between 8V and 15V.
The part also features 22kHz tone signaling, to allow the LNB to be controlled using the Eutelsat DiSEqC protocol. The oscillator starts quickly to facilitate this feature, making it possible to tell the LNB to change its polarization or signal band.
ST has also integrated an I2C bi-directional bus interface into the LNBP21 to offer another way to control the LNB.
The part offers short-circuit protection and diagnostics of the LNB. It features digital cable-length compensation and has over-temperature protection. Protection against electrostatic discharge of up to 4kV on the power input-output pins has been included.
The LNB21 is available in two packages - an SO-20 or a Power SO-20 version.
