• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 16 subscribers
  • Views 99 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TS5A9411: Operation with source or drain voltage centred around 0V

Marek Baczynski
Prodigy 30 points
Part Number: TS5A9411
Other Parts Discussed in Thread: TMUX1104, , EVM430-FR6043, TMUX1136, TS5A22362, TMUX2889

How are MUXes like the TS5A9411 or TMUX1104 expected to behave when swiching a small signal (+- 60mV) centred around ground. See image:

The datasheet states that the recommended voltage on source or drain of the switch is minimum 0V, suggesting that the design shown above pushes the switch outside of its recommended operating range (while still being within the abolute maximum range). However, the reference design EVM430-FR6043 shows the TS5A9411 in this exact configuration. See schematic document TIDRYS5, sheet 3, part U7.

If the TS5A9411 is fine when working with a -60mV input voltage (as shown in the reference design, and despite what the datasheet suggests), can I use other similar MUXes for this purpouse, like a TMUX1104 or TMUX1136? Should I expect better signal quality if using a MUX that is specifically designed to handle negative signal voltages like a TS5A22362 or TMUX2889?

  • 0
    TI__Mastermind 25313 points

    Hey Mark,

    Good question here! So technically speaking you should be fine at -60mV and I wouldn't expect an issue. That being said, even more technically speaking we just won't be able to guarantee the performance at that range. I wouldn't expect it to deviate much but just from a TI standpoint, the datasheet sets the recommended operating conditions and we guarantee only those values; once you exceed it's sort of shift to you being liable for any damage, since the datasheet explicitly says not to do it.

    Now with that in mind, most devices will have a negative clamping diode from the source/drain to ground. That diode will forward bias around -500mV so you wouldn't be forward biasing it with -60mV so it should pass through as it normally would if it were a +60mV. As long as you abide by the current ratings, it should be fine.

    The difference  between using a device this way and using one of the negative signal handling devices like the TS5A22362 and TMUX2889 would just be that we can guarantee performance when you operate in those negative voltages and you'll be able to go 'more' negative

    Thanks,
    Rami