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# TLV9352: Input signal voltage, absolute max

Part Number: TLV9352
Other Parts Discussed in Thread: LM358B, , TLV9102, TLV9152

Hello,

LM358B accepts the input signal voltage exceeding V+ up to 40V.
My customer is looking for a 2ch opamp like it  with lower offset voltage drift and lower offset current drift.

Then I found the below description in TLV9352.
Does it mean it can allow the input voltage exceeding "(V+) + 0.5V" if the current is limited less than 10mA?

Do we have any other good part numbers?

Regards,
Satoshi Obata

• Hello Obata-san,

Please specify the application's V+ and V-.
For a more complete answer, it would be helpful to see the schematic. Please specify the input voltage and frequency range.

To answer your questions, yes if V+ is 40V, then if the input is up to 40.5V - it will not damage the device.

All the best,
Carolina

• HJello Carolina,

Their condition is

V+ = 12V
V-  = 0V
Input signal = usually up to 6V. But due to noise, assumed up to about 20V.
There is a 100ohm resistor between the sensor output and the amp input.
So the input current should be limited to about 0.1 ~ 0.2mA.

The note (3) says that input signal that may swing MORE THAN 0.5V beyond the supply rails must be current limited to 10mA or less.

If the input current is limited to less than 10mA, can the signal swing more than 0.5V beyond the supply rails like this condition?

Regards,
Satoshi Obata

• Hello Obata-san,

The TLV9352 does not accept up to 40V like the LM358B.

However, the condition that you have mentioned:

V+ = 12V
V-  = 0V
Input signal = usually up to 6V. But due to noise, assumed up to about 20V.
There is a 100ohm resistor between the sensor output and the amp input.
So the input current should be limited to about 0.1 ~ 0.2mA.

This is ok. The acceptable abs max common mode voltage is (V+)+0.5V = 12.5V (unless the current is limited). This is due to the ESD protection diodes internal to the op amp, more than 10mA would damage the device.

The output will be (V+) - headroom =

There will need to be some time after the condition is removed in which the op amp takes to recover:

After which, the op amp will behave as expected within the common mode voltage:

All the best,
Carolina

• Hello Carolina,

Let me confirm if my understanding is correct.

If the input current is limited to less than 10mA, any higher voltage than (V+)+0.5V doesn't damage the device.
Is it correct?

Regards,
Satoshi Obata

• Yes.

• Hi Crolina,

Thanks. Do we have any other low cost device like it?

Regards,
Satoshi Obata

• Hello Obata-san,

Is the LM358B not meeting their cost requirements?

All the best,
Carolina

• Hello Carolina,

Yes, LM358B is enough low cost.
They can use it. but they ideally want to use lower offset voltage drift and lower offset current drift than LM358B.

TLV9352 looks like relatively low cost and the offset voltage drift is lower than LM358B.
Then I asked this question. If we have any other option, I want to know it.

Regards,
Oba

• Hey Oba-san,

There are lot of possible options available if they are limiting the input signal to less than 10mA. I can provide a parametric table to help sort by price as necessary.

Here are the ones in LM358B:

All the best,
Carolina

• Hello Carolina,

TSSOP is the target package.

Regards,
Oba

• Hey Oba-san,

Here is a parametric table, filtered by high voltage, TSSOP package and sorted by price: https://www.ti.com/amplifier-circuit/op-amps/products.html#480=2&1498=Catalog&2954=TSSOP&2955=8&261006=PW&1261max=12%3B180&sort=1130;asc&

Considering a lower offset voltage, I suggest TLV9352, TLV9102, TLV9152. All of which will be fine with an input signal larger than V+ if the current is limited to 10mA.

The lowest package price I found was the TLV9102 at \$0.26.

All the best,
Carolina

• Hello Carolina,