INA238: Rating of protection diodes on IN+ and IN- pins

Heiko Berner

Part Number: INA238

What is the current rating of the protection diodes on the INA238 IN+ and IN- pins?

I want to make sure there is no damage to the IC for negative voltages.

The datasheet specifies that the maximum "Input current into any pin" is 5 mA. Can I use this as the rating, or is there a better figure available?

regards

Heiko

over 1 year ago

0 Mitch M over 1 year ago

TI__Mastermind 18185 points

Hello Heiko,

The Voltage range for IN+ and IN- is shown in the datasheet as the "Common Mode Voltage". So, from the datasheet snip below, the minimum voltage that can be on IN+ or IN- is -0.3V.

Regards,

Mitch

0 Heiko Berner over 1 year ago in reply to Mitch M

Prodigy 30 points

I understand this, yes.

The -0.3 V limit comes from the protection diode on the pin, right?

So if I can limit the current flowing through the diode when the voltage goes negative, the protection diode and device will not be damaged.

Regards

Heiko

0 Mitch M over 1 year ago in reply to Heiko Berner

TI__Mastermind 18185 points

Hello Heiko,

Yes, the -0.3 V limit is based off of the internal protection diode circuitry. That being said, the -0.3V limit and the 5mA limit are independent of each other and both need to be kept.

Regards,

Mitch

+1 Mitch M over 1 year ago in reply to Mitch M

TI__Mastermind 18185 points

Hello Heiko,

I will note that some of our older datasheets do say that you can exceed the voltage limit if your current is below 5mA. This line is not in the INA238 datasheet, so if you go below the voltage then you do so at your own risk. Here is a thread that discusses this briefly:

https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/872026/ina213-is-it-safe-if-terminal-current-is-limit-below-5ma

Regards,

Mitch

0 Heiko Berner over 1 year ago in reply to Mitch M

Prodigy 30 points

Thank you

You don't have any internal contacts that could look up what was done in the INA238 design?

Regards

Heiko

0 Mitch M over 1 year ago in reply to Heiko Berner

TI__Mastermind 18185 points

Hello Heiko,

We cannot share specifics about the internal structure of the device, but if you limit the current below 5mA the voltage will not go much below a diode drop from the GND pin. We normally do not want the device to go below GND and we do not have data to support the maximum current for all conditions. That is why there is a limit of -0.3V.

Regards,

Mitch

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INA238: Rating of protection diodes on IN+ and IN- pins