TMUX1248: Will the outputs be diconnected when VDD is off?

Alex Lee

Prodigy 170 points

Part Number: TMUX1248
Other Parts Discussed in Thread: TS5A3160, TS5A3359, TS5A3154

Hello,

I'd like to use TMUX1248 to achived 3 gain options for a amplifier.

Low gain = 1+1/10k

Mid gain = 1+1/(1/10+1/2.7)

High gain = 1+1/(1/10+1/0.68)

Will the output S1 & S2 disconnect when VDD is 0V as above pic shown? so that it can be in low gain state.

If it's not. Are there any other IC options for this purpose?

Thank you very much.

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 271610 points

There are clamping diodes, i.e., there is a low-impedance connection to V_DD. (The absolute maximum ratings forbid Sx/D voltages above V_DD + 0.5 V.)

Use a 3:1 mux like the TS5A3359, or a 2:1 mux with powered-off protection like the TS5A3160 (see the I_{NC/NO/COM(PWROFF)} specifications).

0 Alex Lee over 1 year ago in reply to Clemens Ladisch

Prodigy 170 points

Hi Clemens!

Thank you very much for your prompt reply! I draw a new schematic with TS5A3359

I'm not sure if it's correct....I didn't use all NO1-3 for 3 gain options. R24 is directly connected to R22 to keep the low gain when TS5A3359 is off(IN1, IN2=0). I think this could help to avoid the pop sound when switch the gain?

And NO1 is connected to GND.

Please correct me if I'm wrong....

0 Clemens Ladisch over 1 year ago in reply to Alex Lee

Guru 271610 points

If you are using only two channels, you could also use a 2:1 switch with enable like the TS5A3154.

0 Alex Lee over 1 year ago in reply to Clemens Ladisch

Prodigy 170 points

Thank you Clemens, gonna try one!

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TMUX1248: Will the outputs be diconnected when VDD is off?