Worcester, Mass. - Allegro MicroSystems' four new low-noise block voltage regulators (LNBRs) are designed for satellite set-top box systems. They provide both power and interface signals to the LNB downconverter via the system's coaxial cable. The new chips provide the flexibility of two-way digital satellite equipment control (DiSEqC) encoding or, optionally, legacy system compatibility (non DiSEqC operation).
These regulators feature wide operating voltage range; buck or boost versions are both available. The A8281 (16-pin SOIC) and A8282 (24-pin SOIC) are buck devices. The A8281 output is set to 13 or 18 volts via its VSEL terminal. The A8282 can be set to 12, 13, 18, or 20 volts. Additionally, the A8282's output can be increased by 1 volt to compensate for the voltage drop in the coaxial cable. This device is an improved version of the company's A8283, without a bypass switch. Features include a built-in 22-kHz tone oscillator for DiSEqC encoding, an auxiliary modulation input, and protection against over-temperature, short circuits, and reverse-current conditions.
The A8285 (16-pin SOIC) and A8287 (24-pin) are boost chips that include a I2C bus interface that operates at up to 400 kHz for reading status and for write control.
Both include a tone encoder; the A8287 also comes with a tone detector.
The LNBR family, using the company's ABCD3 (Allegro Bipolar CMOS DMOS 3rd generation) process, is priced from $1.47 to $1.91 each in 1k quantities.