TLV9101: About start up sequence

Tsukui Yusuke

Guru 21930 points

Part Number: TLV9101
Other Parts Discussed in Thread: TLV2401

Hi,

I found this device with a cross-reference search.
Is it safe to input a signal before applying the power supply voltage to this device?
The competition device can input signals to IN+ and IN- before applying V+ and V-.

Best Regards,
Yusuke

over 5 years ago

0 Tim Claycomb over 5 years ago

TI__Genius 15410 points

Hello Yusuke-san,

The input voltage should not be applied before the power supply. If the device is not protected properly damage can occur to the device. You can also have unintended effects such as powering other devices through the ESD diodes as described in "The Self-Powering Device?".

I have not seen a device similar to the TLV9101 that can recommends input signal being present before the supply voltages are applied. Can you please provide the competition device part number so I can look at the datasheet?

Thank you,

Tim Claycomb

0 Ron Michallick over 5 years ago in reply to Tim Claycomb

TI__Guru**** 166216 points

Yusuke-san,

Tim's comments are true but that answer is digital, yes or no. Our world is analog so even simple questions can be complex.

What if the input before power was 1 nano volt or the input current was 1 pA? That is input before power, but no damage could occur. If input was 5V directly connected and was capable of an ampere of current and power bus uses this current then op amp damage would almost be certain.

Old school general rule was 10mA is acceptable risk but op amps are smaller now, so 1mA is the newer general rule although 100uA is a better choice. As Tim says something on the power bus must use this input current and the resulting voltage on the bus must be considered for side effects.

So it may or may not be safe and safer yet is always power before input.

0 Tsukui Yusuke over 5 years ago in reply to Ron Michallick

Guru 21930 points

Hello Ronald, Tim,

Thank you for your response and support.
”Can you please provide the competition device part number so I can look at the datasheet?”
Part number is LT1783.
This device covers signal input before power input.
Do you have a counter device?

Could you give me your advice?

Best Regards,
Yusuke

0 kai klaas69 over 5 years ago in reply to Ron Michallick

Guru 140200 points

Hi Ron,

thanks for this brilliant post!

Kai

0 Tsukui Yusuke over 5 years ago in reply to kai klaas69

Guru 21930 points

Kai-san,

Thank you for your response.

I found TLV9101 with a cross-reference search.
Competitor device can input signals to IN+ and IN- before applying V+ and V-.
Do you have counter device?

Best Regards,
Yusuke

0 Former Member over 5 years ago in reply to Tsukui Yusuke

Yusuke-san,

Can you please reference which competitor device this is?

Thank you,

Daniel Miller

0 Tsukui Yusuke over 5 years ago in reply to Former Member

Guru 21930 points

Hi Daniel,

Competitor device is LT1783.
Let me know if we can give you any other information.
A quick proposal to the customer is required for product replacement.
Could you give me your advice?

Best Regards,
Yusuke

0 kai klaas69 over 5 years ago in reply to Tsukui Yusuke

Guru 140200 points

Hi Tsukui,

have you had a look at the TLV2401?

Kai

0 Tsukui Yusuke over 5 years ago in reply to kai klaas69

Guru 21930 points

Kai-san,

Thank you for your advice.
Is it safe to input a signal before applying the power supply voltage to this device?

Best Regards,
Yusuke

0 Tim Claycomb over 5 years ago in reply to Tsukui Yusuke

TI__Genius 15410 points

Hi Yusuke-san,

The TLV2401 can have the common mode voltage taken up to 5V above the positive supply voltage. However, the specifications of the TLV2401 is very different than the LT1783.

Is it possible to have the power supply turn on before the input signal is applied? Or do you want the feature the LT1783 has as a precaution?

Thank you,

Tim Claycomb

0 Tsukui Yusuke over 5 years ago in reply to Tim Claycomb

Guru 21930 points

Tim-san,

Thank you for your support.

Is it possible to have the power supply turn on before the input signal is applied?
→Not possible due to customer power-up sequence.

Or do you want the feature the LT1783 has as a precaution?
→Yes.

"The TLV2401 can have the common mode voltage taken up to 5V above the positive supply voltage. "
→Thank you for your explanation and introduction.
　Can 5V signal be input when the power supply voltage is 0V?
　Is there a recommended device other than TLV2401?

Best Regards,
Yusuke

0 Tim Claycomb over 5 years ago in reply to Tsukui Yusuke

TI__Genius 15410 points

Hi Yusuke-san,

I do not know of another device similar to the protection in the TLV2401 with similar specs to the LT1783.

Thank you,

Tim Claycomb

0 Tsukui Yusuke over 5 years ago in reply to Tim Claycomb

Guru 21930 points

Tim-san,

Thank you for your kind support.
I will actively propose a TLV2401 to the customer.

Regards,
Yusuke

0 Tim Claycomb over 5 years ago in reply to Tsukui Yusuke

TI__Genius 15410 points

Hi Yusuke-san,

Thank you for promoting our devices! If you need further support please let us know.

-Tim Claycomb

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TLV9101: About start up sequence