0
\$\begingroup\$

I am designing an APD preamp and I need to switch between two bias voltages to the APD 25V and 46V. So I am looking for a SPDT mux that can switch between 25V and 46V in less than 300ns. For clarification:

  • APD is Avalanche Photo Diode.
  • Current needed : 30mA max.
\$\endgroup\$
7
  • \$\begingroup\$ You should explain what an APD is… also your 25-46V signal to be switched: how much current? restriction of impedance or distortion of various kind? \$\endgroup\$
    – Lorenzo Marcantonio
    Commented Mar 12, 2021 at 9:00
  • \$\begingroup\$ Why use an SPDT mux? There are more convenient ways as far as I can tell. \$\endgroup\$
    – Andy aka
    Commented Mar 12, 2021 at 9:03
  • \$\begingroup\$ APD is avalanche photo diode. Need 30mA max current. \$\endgroup\$
    – giora eytan
    Commented Mar 12, 2021 at 9:12
  • \$\begingroup\$ Just for understanding: Why do you need to switch within 300ns? Do you need to cycle bias supplies continuously at MHz frequencies? \$\endgroup\$
    – DLnd
    Commented Mar 12, 2021 at 10:12
  • \$\begingroup\$ can you use a diode for the 25V input and a transistor to switch the 46V \$\endgroup\$
    – Jasen Слава Україні
    Commented Mar 12, 2021 at 10:16

1 Answer 1

Reset to default
0
\$\begingroup\$

I think what you want is power multiplexer. There are dedicated ICs for this task, but it might be hard to find one to work at 46 volts (https://www.ti.com/power-management/power-switches/power-muxes/overview.html)

Example of custom power mux circuit that may work with some optimization copied idea from other post (Switching between two power sources).

Delay 48V to 26V

Schematic

\$\endgroup\$
1
  • \$\begingroup\$ Thanks Ernesto, will try. \$\endgroup\$
    – giora eytan
    Commented Mar 15, 2021 at 6:13

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.