Option to High Voltage Medium (Video) and High Power Devices for Output and VAS Stage

[tiefbassuebertr]

Motorola's new approach arround 1977 - serial cascaded power devices instead very special BjT's with High Voltage UCE

In the German magazine "Funkschau" issue 4/1977, page 61/161 I read the article
"Reihengekoppelte Ausgangsstufe ermöglicht hohe Leistung bei niederigen Kosten" Translate:
Cascaded Power Follower allows High Power and Low Cost at the same Time

A serious option to (often hard to find) high voltage power devices (and also VAS medium power) transistors with not very favorable parameters.

Here my translation from German language:

In opposite to a normal cascode - i. e. fix voltage for the lower transistor - it is to see instead the typical zener also a resistor (see attachement). But similar to the normal cascode, the lower transistor is to be drive while the upper works as a slave. Because the bias voltage (0,5 UCC) corresponds to half the supply voltage UCC , UCE from upper and lower transistor always has the same value. This concept was developed in Motorola's European consumer laboratory

For this approach Motorola has developed a very special series of power devices with very high hfe (>20 at 10A).
There are three Uce groups:
1) 50V: BD364/365
2) 60V: BD366/367
3) 80V: BD368/369

The number of cascaded series devices is of course not limited to two pcs.

The original application paper from Motorola wanted.

[tiefbassuebertr]

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