eclips oscillator

ECL seems well-suited to generating sines also, as it kinda has a soft-limiting "tanh-shaper" built into it to begin with

Old timey NOR-gate:

bias it into class C with a negative voltage below Vee on the inputs and connect an LC back to the input from not-Q and I think it should sing. For 1+ GHz maybe some trace inductance and an inter-digital capacitor would be enough.

Series LC to be specific if that wasn't clear

The old 10K parts had low gain and could be used as linear amplifiers. The EL and EP gates have a lot more gain, so have harder edges.

onsdag den 2. februar 2022 kl. 23.07.13 UTC+1 skrev John Larkin:

Oscillates at 1.5 GHz, reasonable square wave, bad tempco.

Can be tuned down maybe 20% with C2.

There are tons of "clock generator" chips. Some are actually just buffers or dividers. Some are very complex synthesizers. Most are unavailable.

This should work.

That looks similar to the late Jim Thompson's MC1648.

Cheers

Phil Hobbs

Substituting a tapped inductor (drive the tap, sense/resonate the endpoint) would improve the slew rate. Tapped inductor is a gain boost, and the chip has input clamps.

The MC1648 is remarkably old. The Motorala - ON Semiconductor - ECLinPS parts go back to the 1990's,, and the MC1648 shows up in the 1973

The topology may be similar, but the transistors are going to be a lot smaller that the ones Jim designed in.

That chip has lots of gain, and we have lots of low-nH 0603 inductors in stock.

Not all that much gain at 1.5 GHz.

And you don't seem to know enough about how your SMD inductors work. Most of the ones I used printed a straight conducting track onto a lump of ferrite.

Getting much magnetic coupling between them might be difficult. Ferrite beads don't look as neat, but at least you know exactly the route the current follows.