4
\$\begingroup\$

I am looking for a chip that could handle DPDT (or SPDT, or ultimately SPST) analog switch for audio routing (in the mOhm range resistance) and can guarantee one state when there is no power supply.

DPDT example

I have been looking around in manufacturer portfolios and results were those two cases :

  • Either High-impedance is guaranteed on power-off (between both NC/COM and NO/COM)

  • Or the state of the switch can't be predicted in no supply mode

So both of those cases don't guarantee one specific state in no supply mode.

Do you know any component that could suit my needs ? Thanks in advance

\$\endgroup\$
  • 10
    \$\begingroup\$ They are called electro-mechanical relays. Solid-state switches use active components and pretty much always need some form of power to do this. Only way to do what you want is with a) MEMS b) depletion-type FETs c) floating-gate devices. I don't know if any of the above can achieve the required few mΩ on-resistance you need (heck, even power fets tend to not pull that of...) \$\endgroup\$ – Joren Vaes Aug 17 '17 at 8:02
  • \$\begingroup\$ Why not just supply power to it? \$\endgroup\$ – Jason Han Aug 17 '17 at 9:35
  • 1
    \$\begingroup\$ @JasonHan To be a little more precise I want to make an USB to jack adapter. In normal function the usb transports D+ D- and Vdd/gnd. When the jack adapter is plugged, no more Vdd and the analog audio should go directly to the headphones sound drivers by using the D+/D- of the cable as SpeakerLeft/SpeakerRight. \$\endgroup\$ – chillyjee Aug 17 '17 at 14:25
  • 5
    \$\begingroup\$ "I want to make an USB to jack adapter". To connect what to what, exactly? The signals on a USB port are completely different to audio, either at line level or speaker level. \$\endgroup\$ – Finbarr Aug 17 '17 at 15:22
  • 1
    \$\begingroup\$ @Finbarr Remember those USB to PS2 mouse adapters? I gather chillyjee wants to do something like that. A mouse with two plugs would be impractical so instead they make a physical-layer adapter from one to the other, that tells the mouse to switch modes. \$\endgroup\$ – user253751 Aug 28 '17 at 1:20
1
\$\begingroup\$

Have a look at MAX14589E. It guarantees the switches are in OFF state when there is no supply.

https://www.maximintegrated.com/en/products/analog/analog-switches-multiplexers/MAX14589E.html

\$\endgroup\$
0
\$\begingroup\$

Might be a bit late for this but you could use bistable latching relays like the TE IM41TS for example. That one is DPDT.

You can send a pulse to the coil to set or reset the state of the contacts and they'll latch until they receive another pulse with reverse polarity. That way you can save some power since you aren't constantly drawing current thru the coil to keep it on.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

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