1997-01-15 , E/DS-467/110

Philips Semiconductors' new BB146 and BB147 high ratio varicap diodes offer a uniquely high capacitance ratio, approximately twice that of standard devices. This delivers a much larger range of automatic tuner alignment, reducing the cost of tuning circuitry in TV and monitor applications.

"With their extraordinarily high capacitance ratio, these new varicaps not only extend tuning ranges in UHF and VHF circuits, but we also expect them to open the door to a wide range of new and innovative tuner solutions", said Rainer Buschke, International Product Marketing Manager in Philips' Discrete Semiconductors business group.

In addition, these devices also offer excellent capacitance matching characteristics by using a proprietary direct matching assembly (DMA) procedure and gliding matching, allowing for simple tuner alignment. In a gliding sequence of 8 diodes, capacitance matching values of less than 1.6% for the BB146 and less than 2% for the BB147 are achieved.

The BB146, for extended UHF tuning, provides a minimum capacitance ratio of 17.5 and a maximum of 23 at 1 MHz. With a continuous reverse voltage of 28 V, this results in a diode capacitance of 1.9 pF and a typical capacitance ratio of 20. Under the same conditions the BB147, for extended VHF ranges, offers a diode capacitance of 2.6 pF and a typical capacitance ratio of 40 (min. 35, max. 43).

These diodes, manufactured at Philips' Hamburg plant, are fabricated in planar technology and encapsulated in the very small SOD323 plastic SMD package. For high volume sales they are expected to retail at US$ 0.04 and US$ 0.06 for the BB146 and and BB147 respectively.