cascode amplifier

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cascode amplifier

[′ka‚skōd ′am·plə‚fī·ər]
An amplifier consisting of a grounded-emitter input stage that drives a grounded-base output stage; advantages include high gain and low noise; widely used in television tuners.

Cascode amplifier

An amplifier stage consisting of a common-emitter transistor cascaded with a common-base transistor (see illustration). The common-emitter-common-base (CE-CB) transistor pair constitutes a multiple active device which essentially corresponds to a common-emitter stage with improved high-frequency performance. In monolithic integrated-circuit design the use of such active compound devices is much more economical than in discrete designs. A similar compound device is the common-collector-common-emitter connection (CC-CE), also known as the Darlington pair. See Integrated circuits

Cascade amplifierenlarge picture
Cascade amplifier

The cascode connection is especially useful in wideband amplifier design as well as the design of high-frequency tuned amplifier stages. The improvement in high-frequency performance is due to the impedance mismatch between the output of the common-emitter stage and the input of the common-base stage.

Another important characteristic of the cascode connection is the higher isolation between its input and output than for a single common-emitter stage, because the reverse transmission across the compound device stage is much smaller than for the common-emitter stage. In effect, the second (common-base) transistor acts as an impedance transformer. This isolation effect makes the cascode configuration particularly attractive for the design of high-frequency tuned amplifier stages where the parasitic cross-coupling between the input and the output circuits can make the amplifier alignment very difficult. See Amplifier, Transistor

References in periodicals archive ?
The TPH3002PS is based on a cascode configuration of a GaN on Silicon HEMT transistor to hold the high voltage and a standard low voltage MOSFET to drive high frequency and to make a normally-off transistor from a normally-on GaN HEMT.
MNd is a Current-Mode Background Suppression (CBS) circuit that lead overflow current from cascode current mirror to ground to suppress over charge of integration capacitor.
today announced at APEC 2015, in partnership with ON Semiconductor, the introduction of two co-branded 600V gallium nitride (GaN) cascode transistors and a 240W reference design that utilizes them.
Several papers present AB class current conveyors using improved current mirrors: cascode mirror (Minaei, 2003), high-swing mirror (Calvo et al.
Since folded cascode circuit is commonly used in amplifier applications, our calculations are based on it.
A current source sets the bias on differential pair and an additional pair of transistors act as a cascode for improved linearity and bandwidth of the differential stage.
The device operates from 80V and 12V power supplies and features a 200MHz, cascode output stage capable of driving 8pF, 40Vp-p swing at a maximum rise / fall time of 3.
The LM2409 operates from 80V and 12V power supplies and features a 40MHz cascode output stage capable of driving 8pf, 40Vp-p swing at a maximum output voltage of 68VDC.
In addition, thanks to its cascode configuration and dedicated bipolar technology the device offers a square reverse bias safe operating area, enabling it to work in hard switching topologies.
The cascode transistor isolates the second gain stage collector from seeing the large signal swings that now appear at the output of the amplifier.
Sirenza Microdevices , a leading designer and supplier of high-performance radio-frequency (RF) components for communications equipment manufacturers, today announced the recent award of US patent #6, 806,778 entitled "Darlington Cascode.
a leading supplier of wireless and broadband solutions, today announced that it was assigned patent 6,803,824 for a new dynamic input matching technology for cascode circuits with the ability to improve input matching at high and low gain settings.