INA210: Schematic Review

user6191674

Part Number: INA210
Other Parts Discussed in Thread: TLV431

Hello，

I have a design to use INA210. INPUT is 12V/1.5A controled by switch. The OUTPUT is 3V to MCU. (INA210's GAIN is 200. Vout = 1.5A*10mOhm*200 =3V)

Do you have any suggestions on the below schematic? Whether Power on Sequence has any effect?

over 3 years ago

0 kai klaas69 over 3 years ago

Guru 140200 points

Hi,

provided you don't violate the absolute maximum ratings given in section 6.1 of datasheet, there should not be any issue with the power-up sequence.

But please remove C46. Or add an isolation resistor forming a suited charge kick back filter for the ADC input. Which ADC do you use?

Kai

0 Guang Zhou over 3 years ago in reply to kai klaas69

TI__Mastermind 27390 points

Hi,

The schematic looks good. Here are some recommendations to make it robust:

(1) Swap the amplifier with its B or C version. Please see below excerpt from the datasheet for reasoning:

(2) Add a 150Ohm resistor between pin 6 and C46 to ensure stability.

(3) Consider output clamp or a lower power supply (is a potentially 12V output acceptable to “ADC5” input?)

Regards, Guang

0 user6191674 over 3 years ago in reply to Guang Zhou

Prodigy 30 points

Hi，

Thanks for your answers.

(1) The power supply has ESD protection at the front end.

(2) This is good advice. Resistor is in series between the PIN6 and C46?

(3) ADC input is 3.6V max. INA210 has a potentially 12V output, but I need 3V output.

I want the INA210's power supply to be controllable. The 12V power supply is controlled by MOS.

Is it feasible to control the input of 3.3V by pulling up and down the voltage of the resistance.

Thanks

0 Guang Zhou over 3 years ago in reply to user6191674

TI__Mastermind 27390 points

Hi,

Yes the resistor is placed in series between Pin6 and C46.

I can’t visualize this scheme – “control the input of 3.3V by pulling up and down the voltage of the resistance”. If possible, a lower voltage supply such as 3.3V, is probably the safest bet.

Regards, Guang

0 user6191674 over 3 years ago in reply to Guang Zhou

Prodigy 30 points

Hi，

We want to control the power supply by switch. So using resistor divider to make the input 3.3V

Thanks

0 Guang Zhou over 3 years ago in reply to user6191674

TI__Mastermind 27390 points

Hi,

Thank you for the diagram.

The resistor divider works for certain devices that draw very low quiescent current. While it is up to interpretation, the INA210 supply current is not negligible at 115uA over temperature range. The resistors need to be significantly smaller, maybe on the order of 40x for it to work.

You may also consider a shunt regulator, something similar to TLV431. Such a regulator provides better performance yet is not too costly. For expert support on such regulators, you may visit the corresponding forum here.

Regards, Guang

0 kai klaas69 over 3 years ago in reply to Guang Zhou

Guru 140200 points

Hi Guang,

are the absolute maximum ratings still valid then?

Kai

0 Guang Zhou over 3 years ago in reply to kai klaas69

TI__Mastermind 27390 points

Hi Kai,

Of course, these datasheet specs are still valid. And they are “pin to pin”.

Regards, Guang

0 kai klaas69 over 3 years ago in reply to Guang Zhou

Guru 140200 points

Thanks :-)

Kai

0 Guang Zhou over 3 years ago in reply to kai klaas69

TI__Mastermind 27390 points

You’re welcome.

Regards, Guang

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INA210: Schematic Review