INA381: Current sensing IC recommendation

JH Shin

Guru 10340 points

Part Number: INA381

Tool/software:

Hello,

My customer is looking for a current sense IC that can support the following features.

- Detects current of 8mA to 20mA (5V) and outputs High(open-drain) or Low level

- They want to distinguish between cases where there is no current or a very small current flowing and cases where there is 8mA to 20mA flowing.

Could you please recommend the most suitable low-cost solution among TI products to implement this function?

Thank you.

1 month ago

0 Clemens Ladisch 1 month ago

Guru 311080 points

The INA381 supports these features.

These current sensors measure the voltage drop over a shunt resistor (and then amplify it by a fixed factor), so you have to size the resistor correctly. How much of a voltage drop can you actually afford? The INA381 has an input offset error of up to 150 µV. Assuming that you want a voltage drop of 150 mV for the full current, you would need a resistor of 0.15 V / 0.02 A = 7.5 Ω.

0 Mallika Senthil 1 month ago

TI__Expert 5080 points

Hi JH,

I agree with the Clemens, the INA381 should meet specs. The following link will show you other current sense devices with an integrated comparator.
https://www.ti.com/amplifier-circuit/current-sense/products.html#-2=contains%3Bcomparator&

Best,
Mallika Senthil

Amplifiers

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INA381: Current sensing IC recommendation