The dual LNB regulator IC has features and functions applicable to all dual-tuner satellite receiver designs. It consists of a monolithic switching and linear voltage regulator, specifically designed to provide the power and interface signals to an LNB down converter via coaxial cable in satellite TV receivers systems.
The device has the boost switch and compensation circuitry integrated inside the device, and so requires few external components. The boost converter's switching frequency (563 or 939 kHz) and user-controlled current limit (250 to 950 mA) allow compact external components to be used. A “sleep” pin is available to maximise power savings and to quickly shut down the device if required without the need for I2C control.
The A8302 can either provide an internal 22 kHz tone or accept an external 22 kHz tone for DiSEqC communications. It also has integrated 22 kHz tone detection capability. An internal bypass FET gate drive simplifies full 2-way DiSEqC communications if needed. An early power failure warning capability helps to initiate shutdown routines.
The maximum output reverse current can be set using a control bit. A comprehensive set of fault registers is provided, which comply with all the common standards including: overcurrent, thermal shutdown, undervoltage, and output out of range.
Also available in Allegro’s fifth-generation LNB regulator family are several single-channel devices: the A8300 and A8300-1 (targeted at two-way DiSEqC and LCD TV applications) and the A8304 (targeted at one-way DiSEqC applications).
The A8302SETTR-T² comes in a 5 × 5 mm QFN package (suffix ET) with exposed pad for thermal dissipation.
Allegro Microsystems; www.allegromicro.com