Nortel Networks Corporation

Northern Telecom Limited

William Kung

John Ilowski

Stephen J Kovacic

Duljit S Malhi

M Jamal Deen

A conventional differential transistor pair is provided with a dynamic bias circuit. The input voltage signal for the differential pair is also full-wave rectified and the rectified signal is used to bias dynamically the differential pair while the input voltage signal is being applied. One or more bias transistors having a control electrode fed with the rectified signal is connected in series with the differential pair. The result is that as the input signal magnitude increases the amount of bias increases dynamically and increases linearly for larger signals. Desired responses other than linearity can be achieved by making the signal that is fed to the rectifier vary according to any predetermined function.

Wide-band linearization technique

The present invention deals with the problems related to thermal runaway and over-voltage breakdown in integrated circuits using a series of power transistors interconnected in a parallel circuit arrangement. The general technique described consists of a protection scheme that involves the application of a fusible material to form ballast resistor components. These components are connected in series with each of the transistors in the integrated circuits. The main advantages are significant area and cost savings in the manufacturing of the integrated circuits as well as an increase in their yield, thereby reducing costly field maintenance and equipment returns.

Protection scheme for multi-transistor amplifiers

In a tree mixer having an input differential pair of transistors as a gain stage and two differential pairs of transistors (transistor quad) as a mixing stage, a further transistor quad in the mixing stage is provided. The further transistor quad is complementary with respect to the first transistor quad. A DC offset is applied between respective mixing inputs of the two transistor quads and the local oscillator input signal is applied to both inputs. The two transistor quads are interconnected through summing circuits such as current mirrors. By appropriately setting the DC offset the mixer can be operated in class A, B or AB as desired.

Tree mixer operable in class A, B or AB

A gate controlled lateral bipolar junction transistor (GCLBJT) device for an integrated circuit and a method of fabrication thereof are provided. The GCLBJT resembles a merged field effect transistor and lateral bipolar transistor, i.e. a lateral bipolar transistor having base, emitter and collector terminals and a fourth terminal for controlling a gate electrode overlying an active base region. The device is operable as an electronically configurable lateral transistor. Advantageously a heavily doped buried layer provides a base electrode having a base contact which surrounds and encloses the collector. The surface region between emitter and collector is characterized by lightly doped regions adjacent and contiguous with the heavily doped emitter and collector, which effectively reduce the base width of the bipolar transistor and improve operation for analog applications.

Growing community of inventors

Nepean, Canada

William Kung