What’s All This Varactor-Input Amplifier Stuff, Anyway? (.PDF Download)

    Sept. 9, 2016

    In 2008, Marcello Salvatierra took the picture above of a circuit Bob Pease had just built. Bob told him it was based on a circuit that Jim Williams did in 1967. Despite working for competitors, Bob and Jim were good friends.

    I did not recognize it, so I asked some analog aficionados what it might be. Alan Martin redrew the circuit in Altium, which made its signal paths clearer. Bob Dobkin, CTO of Linear Technology, recognized it immediately. He said, “At a glance, it looks like a varactor input op amp, like the Philbrick P-2”. This makes sense; Pease wrote a chapter about the P2 in Jim Williams’ analog design book...

    Register or Sign in below to download the full article in .PDF format, including high-resolution graphics and schematics when applicable.

    Download

    Continue Reading

    Sponsored

    Stricter guidelines imposed by version 3 of the IEC standard for harmonic current emissions push designers to embrace power-factor-correction methodologies.
    The flyback topology is a versatile, widely used, switched-mode power-supply design with some interesting characteristics that brings performance and BOM advantages to many applications...
    Significant complications arise when trying to get your power supply working from a wall outlet.
    Power supplies are everywhere and there are a lot of options for designers. Knowing the differences can help in selecting one for a particular application.