TMUX1111: Device does not work properly with VDD = 3.0 (V) and VSEL = 3.0 (V)

Please show the schematic of your circuit. And what does "does not work" mean; what happens?

Hi Woojoong,

The TMUX1111 should work properly at 3V and the switch should be high impedance when a 3V signal is applied to the select pin.

However, if you could tell me some more details about the problem so that I can help support you it would be greatly appreciated.

What is the behavior you are seeing? Oscilloscope shots of the input, output, and select pin would be helpful as well to see if I can diagnose your problems.

Best Regards,

Parker Dodson

Thank you very much for your quick reply.

I did give  VDD = 3.0 (V)  [+V] and VSEL = 3.0 (V) [by GPIO] on the device.

On the data sheet, it should be close to an open circuit, but it wasn't.

The resistance at this time was measured to fluctuate between 60 and 80 kilos.

I definitely don't think it's a problem with the device, but I don't know what changes make in the configuration to form an open circuit.

Hi Parker Dodson,

Thank you very much for your quick reply.

I did give  VDD = 3.0 (V)  [+V] and VSEL = 3.0 (V) [by GPIO] on the device.

On the data sheet, it should be close to an open circuit, but it wasn't.

When resistance is measured through a multimeter, The resistance was measured to fluctuate between 60 and 80 kilos.

I definitely don't think it's a problem with the device, but I don't know what changes make in the configuration to form an open circuit.

Thank you very much for your kindness

Best Regards,

Woojoong Kim

With SEL high, the resistance should be approximately infinite, much larger than 100 kΩ.

Is there anything connected to the S/D pins? If yes, what are the voltages at the S/D pins, relative to GND?

Thank you very much for your quick reply.

Q. Is there anything connected to the S/D pins?

A. No. At first, I just used multimeter directly. And i ALSO use Vs = 1.6 V and VD= 0 (GND)

    Both i am fail...

Hi Parker Dodson,

Thank you very much for your quick reply.

Q1. did you ground the D side when you were applying a signal to the S side? 

A1. Yes i did.

Q2. How are you measuring the off state impedance of the device?

A2. It  is about 2 ohm that the off state impedance measured by multimeter. ( Vs = 1.6 V and VD= 0 (GND) V )

Q3. Is D connected to Ground or a load, if load what is its resistance?

A3. D is connected to Ground . 

Is there a problem because the supply voltage(VDD or  VSEL) is not 5V?

Best Regards,

Woojoong Kim

Hi Woojoong,

So no, the problem is not the voltage supply being too low. 

I am still unsure as to what is causing the problem.

Have you been able to replicate the problem on multiple boards? 

Is there anyway you could share a snippet of the schematic with this part, not the diagram you sent earlier, but all the connections on the part and any passives that may be also on the pins. This will help me better understand how the part is being used. 

Also a few sanity checks may help when troubleshooting the issue:

1. Measure the current going into the S channel, if this in the microamp range, the switch is definitely conducting, this is to help confirm the impedance of the switch. 

2. Check the board for short circuits or anything that could cause interference. 

3. Probe all the lines of the board to make sure that you are getting the voltage at the pins that you have designed for. 

3.A Oscilloscope shots can also help show if there is any glitches that aren't as apparent  on a multimeter

Best,

Parker Dodson