Analog switches and SDIO/SPI devices

[ledtester]

I was wondering if an analog switch such as the TS3A5018 (datasheet) would be suitable for switching the SDIO/SPI interface lines between two SD cards.

In this case data is written to the SD card at about 100 MB/minute.

The datasheet says the bandwidth of the TS3A5018 is 300 MHz into a 50R load. Would that also be indicative of its performance in this application?

This is an idea to off-load data from a camera by electronically switching between two SD cards.

[julian1]

Why analog. Do you want to send over fixed impedance line? Why not a digital transceiver. The SD cards on arduino breakouts commonly rely on LVC245A.

[rstofer]

Can't they both share the bus and just use the SS Slave Select line?

[ledtester]

Can't they both share the bus and just use the SS Slave Select line?

I want to access the other card from another microcontroller. And I can't modify the firmware of the camera.

Why analog. Do you want to send over fixed impedance line? Why not a digital transceiver. The SD cards on arduino breakouts commonly rely on LVC245A.

It could be done with 4 transceiver chips. Possibly could be done with 2 if I give up the ability of independent HI-Z control.

Think of it as a camera writing to card #1. Then it is redirected to write to card #2 while a microcontroller connects to card #1 to process the data. And then another switch happens, etc.

[David Hess]

Yes, analog switches can be used as digital multiplexers in most digital applications and may even be preferred in some cases.