Latching relays

On Thursday, September 26, 2019 at 12:50:02 PM UTC-4, Winfield Hill wrote:

Phil Hobbs wrote...

On 9/26/19 8:47 AM, Winfield Hill wrote:
pcdhobbs@gmail.com wrote...

Capacitance. I needed to bootstrap the coil-to-contact
capacitance (0.4 pF), because it would have trashed the bandwidth.

What were the bandwidths for the two gains?

Just trying to dig this up out of my old emails--it was from 2012-3,
so i forget. Here's a preliminary test result:
https://electrooptical.net/www/sed/QceptBigTIA_Wringout.pdf

The bandwidth was around 10 MHz or so, because the coupling between
the input signal and the TIA was capacitive, and it was the voltage
we cared about.

Ah, a capacitive-coupled-input with a gain of about 10, nice!


--
Thanks,
- Win

A subsequent version running at 40G (2x 20G in series, with the midpoint bootstrapped by a matching lower-Z string) got the effective shunt capacitance down to about 14 nF, so we ran at a voltage gain of about 70.

Fun.

(In most cases this sort of elaboration is a net SNR lose, but up in the gigohms it turned out to be a win. Pity about the company--they got killed off by a big customer not paying on time, to put it mildly.)

Cheers

Phil Hobbs

Cheers

Phil Hobbs