TS3USB221 OR TS3USB3000

Yes,

Looking at your BW requirements the TS3USB3000 would be overkill for this application (and more costly!).  I would advise using the TS3USB221 as it could fully support your application requirements

Let me know if you any more questions.

Regards,

Andrew

Hello TI, please confirm that both of these parts would also be useable as switches for analogue signals, e.g. audio. This does seem to easily be the case but is not one of the listed applications. Unfortunately, TI do not seem to offer cheaper non-BGA, small (<= 3 mm^2) 2:1 analogue multiplexors supporting a low Ioff.

Bernhard,

Yes both the TS3USB221 and TS3USB3000 are general use multi purpose analog switches usable for analogue signals as long as the signals are within the recommended operating values listed in the datasheet (0-5 V for TS3USB221 and 0-3.6 V for TS3USB3000).

Audio signals typically are centered around 0V and will have a positive and negative swing, for example +/-1V peak to peak,  which would be outside the recommended operating range of the TS3USB221 and TS3USB3000.  TI has several analog switches specifically designed to handle these signals with negative swing like the TS5A22364, TS5A22362, TS3USB224, etc.

I have sorted the USB switch parametric table on TI.com to show that there are 7 usb switches that are non-BGA, small (<= 3 mm^2) 2:1 analogue multiplexors supporting a low Ioff (<4uA max)

Could you describe the signal you are wanting to switch and the application so we can locate you an appropriate solution? 

Thank you,

Adam

Hello Adam,

Thank you for your detailed response, which is much appreciated. I like the OFF-state leakage current column in this parametric table - would it be possible to also introduce such a column in your other selection tables, e.g. in this case the analog-switch table: www.ti.com/.../analog-switch-products.page, but also in general in all your logic selection tables? Ioff support is becoming increasingly relevant and this would save a lot of effort in many designs.

The closest 'normal' analog-switch part is the TS5A63157 (cost-effective but unfortunately only available in a relatively large package) and perhaps the TS5A21366 (not 2:1 multiplexor and higher Ioff), but these can only be found by careful study of all analog-switch datasheets. Many other parts offer a low off-current only on the enable signal but this is not what is truly meant by Ioff.

In this particular case the application is three-fold: one to switch a low-level raised cosine 0.8Vpp clock biased more or less around midrail, another to switch a CMOS/TTL-level clock and another to switch an open-collector signal. Use in a correctly biased audio switching application is also foreseeable.

I am aware of TI's swing-around-zero capable parts (which we use in other designs). Those would have been preferable here too unfortunately but do not feature low Ioff and small non-BGA packages if I recall correctly.

The TS3USB224 which you mention I have not yet seen - is this a new part?

Thanks,

Bernhard

Bernhard,

We really appreciate your feedback on the Ioff spec being in the selection tables.  We are constantly trying to think of ways to make it easier for our customers to work with our products.  We are in the process of adding these types of specs to all of our analog switches but as you can imagine it is a labor intensive process and will take sometime.  Please feel free to visit our page in the future and offer more suggestions as you see our website evolve.  

I have made a mistake and meant to type TS5USBA224 which has an integrated USB 2.0 or Audio switch.  This comes in a small 1.8mmx1.4mm QFN package with leakage in the 10s of nA.  

As you are not utilizing the differential USB path you may use the D+ and D- pins of our USB switches as 2 single ended paths.  This device will give you a 1:2 mux solution with 2 channels for both of your clocks.  If you want the 1:2 switching for 2 clock signals and an audio path you can look at the TS3USBA225 which has additional integrated channels.

Adam