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Diodes claims LNBs, control ICs boost STB efficiency

Posted: 08 Aug 2012 ?? ?Print Version ?Bookmark and Share

Keywords:Diodes? low noise block? power management? STB? satellite tuner?

Diodes Inc. has introduced a line of low power low noise block (LNB) power management and control ICs for set-top boxes (STB), TVs with built-in satellite tuners and PC satellite tuner cards. The company claimed the devices are geared to increase product efficiency and reliability, and offer manufacturers the flexibility to address global satellite TV standards.

Three single-output devices are initially being made available: the high-current ZLPM8010 (750mA) and low-current ZLPM8011 (450mA), both of which are full-featured and support DiSEqC 1 and DiSEqC 2 standards; and the low-current ZLPM8012 (450mA), with a reduced feature set and supporting the DiSEqC 1 standard only.

To increase overall STB system efficiency, the ICs' low quiescent current boost converter operates from a standard 12V power rail and employs a low Rds(on) (270m) MOSFET power switch. In turn, the converter supplies a very low volt drop (500mV) LDO regulator, providing control signals and low noise power output to the LNB. The devices' standby operating mode puts it into a deep sleep mode in which current consumption is only 600?A.

The LNB supply generated by the ZLPM8000 series is highly programmable, being configurable in 0.25V steps from 10.25V through to 19.5V. This enables designers to match with any system architecture and adjust for cable drops or poorly performing LNBs. The devices' integral protection and diagnostic features include overcurrent limit, line short and open circuit, over temperature shutdown and under voltage alerts.

Diodes' power solutions for STBs

An integrated 22kHz tone generator provides for DiSEqC and traditional band switching control that is reliable even under no-load conditions. To enable two-way communication between LNB and STB, the ZLPM8010 and ZPLM8011 include the market-leading Zetex LNB DiSEqC receive technology, which allows high reliability detection of a wide range of signals while assuring excellent signal rejection.

Fully configurable via I2C interface or standard logic inputs, the ZLPM8000 series devices are easily tailored to handle regional variations in satellite TV standards. Using the I2C port, designers can access an array of device functionality, including LNB control, output adjustment, a four-level current limit, low-current standby and various line check features.

The three devices in the ZLPM8000 product line are provided in the compact 20-lead, 4-by-4mm QFN package and are pin-compatible, enabling product designers to change the IC to match local market requirements without having to modify PCBs.

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