suggestions regarding DG411 switch

[shrinivas.gotur]

Hi all,
I was wondering if i get similar analog switch as of DG411 with improved characteristics, say, continuous current should be greater than 30 ma as of DG411.share your opinions please
thanks in advance

 

[betwixt]

Generally yes, if you can find a suitable one but analog switches are not intended as switched current sources, their 'on' resistance is far too high. The absolute maximum rating of the DG411 is 30mA per pin but in normal use it would be very much less than that. What is your application?

Brian.

 

[shrinivas.gotur]

Thanks for your reply,
actually it is part servo control loop and we had some failures in DG411 switch and when we did failure analysis i.e decap analysis we found high current spikes on the input pins of dg411 i.e 2 and 7.since we are unable to put resistors in the input path we are thinking to replace switch with alternate part but with same characteristics and with more continuous current than 30 ma

 

[betwixt]

Sounds like bad design to me. If you really have to increase the capability of the existing switch, I would consider replacing them altogether with a MOSFET and appropriate control logic. In other words rebuild the DG411 using discrete components.

Brian.

 

[Analog Ground]

Check out the Maxim MAX4601 analog switch. Low "Rds on" of 2.5 ohms and looks to be pin compatible. https://www.maximintegrated.com/datasheet/index.mvp/id/1952
Analog Devices has similar parts as well. Make sure nothing is causing a switch I/O to exceed the power supply voltages with the switch powered or unpowered. Clamp diodes to the + and - supplies are commonly added for protection.