TMUX1511: Regarding leakage currents of TMUX1511 in battery powered application.

Jagdish Karamchandani

Part Number: TMUX1511
Other Parts Discussed in Thread: TMUX1111

Hello TI support.,

We intend to use TMUX1511 in battery powered application where we think of below use case,

Application

We shall be using TMUX1511 between uC & peripheral interfaces like SPI, SAI, UART, I2C & GPIOs. Please see attached scheme where to save quiescent current during sleep mode a analog switch will be used controlling 2.5V power to TMUX1511 & other peripherals. So during active state uC will switch ON 2.5V to TMUX1511 & other peripherals, take sensor readings & send over data over bluetooth. During sleep mode, uC will switch OFF 2.5V to TMUX1511 & all other peripherals & enter itself in standby mode. Internal RTC in uC will keep waking uC every 1 hr & repeat the cycle as mentioned above.

Queries,

1. Will TMUX1511 all Sx & Dx pins remain in high impedance when its VDD=0?

2. The IPOFF current (10nA) specified in datasheet for Vs=0 to 3, VDD=0 is per pin, right? So if we have 8 pins connected in our application total leakage during sleep mode could expected to be 8X IPOFF=8X 10=80nA. Is my understanding correct?

3. Any more leakage or current consumption in TMUX1511 when VDD=0? or that only which mentioned in point-2.

4. Any other better switch could be recommended from TI for above mentioned application.

Regards,

jagdish

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 260270 points

1. Yes; the recommended operating conditions allow voltages above V_DD, up to 3.6 V.

2. Yes; it's per pin.

3. Nothing else is connected to the switch.

4. All other switches with powered-off protection have worse leakage currents. (But in general, I would leave the switch powered, and choose a low-leakage device like the TMUX1111/2, with a supply current of 5 nA typical (but unknown maximum).)

0 Jagdish Karamchandani over 1 year ago

Expert 1420 points

Hello Clemens,

Thanks for clarifying the queries & suggestion of TMUX1111/2. Just a query for TMUX1111/2 is this doesn't seems to have Ioff feature, now when it remains powered & OFF ( while 2.5V is cut to other peripherals), will the OFF leakages remain as specified in datasheet with range of Vs/ Vd from 0 to 2.5V on either side?

Regards,

jagdish

0 Clemens Ladisch over 1 year ago in reply to Jagdish Karamchandani

Guru 260270 points

The TMUX111x must not be used with I/O signals when powered off; it makes sense only if you leave it powered in together with the microcontroller.

0 Jagdish Karamchandani over 1 year ago in reply to Clemens Ladisch

Expert 1420 points

What I meant in previous question was uC & TMUX1111/2 will remain powered while rest of all peripherals controlled through 2.5V power switch will remain unpowered. In this condition unpowered signal lines of peripherals may present any voltage level ranging from 0 to 2.5V, so we need to be ensure that OFF leakages will remain in range as specified in datasheet.

I hope it is clear now, please advise.

0 Clemens Ladisch over 1 year ago in reply to Jagdish Karamchandani

Guru 260270 points

The values specified in the electrical characteristics table are only for two specific I/O voltages, but the drain/source leakage of a MOSFET does not depend on the drain voltage, so these values should by valid for all I/O voltages.

0 Jagdish Karamchandani over 1 year ago in reply to Clemens Ladisch

Expert 1420 points

OK got it. Thanks,

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TMUX1511: Regarding leakage currents of TMUX1511 in battery powered application.