INA186: Use two unidirectional current sense amp to create a bidirectional current sense amp

Shawn Zhou

Part Number: INA186
Other Parts Discussed in Thread: INA216, INA181, INA138, INA139, INA281, TLV9061, INA190

Dear Sir,

We plan to use two unidirectional current sense amp to create a bidirectional current sense amp for cost consideration. (INA186)

Please help us confirm it as below, thank you.

e.g.

1. Vcc = 1.8~ 5.5V.

2. Use INA216 to replace by MAX4127 for unidirectional current sense amp.

11 months ago

0 Angel Rodriguez de San Miguel Bermudez 11 months ago

TI__Expert 6810 points

Hi Shawn,

I would recommend taking a look at INA181 (INA181 data sheet, product information and support | TI.com) for your design.

If cost is the priority INA181 is our cost-optimized solution for bi-directional current sensing.

You can take a look at all of our available current sensing devices by using our parametric search tool. These are our available current-sensing devices that are analog and bi-directional: Current-sense amplifiers product selection | TI.com

You can further narrow down the search if you input additional specifications.

Otherwise, if you are just looking for TI replacement parts for the same design you have provided in the picture, using our Cross-Reference tool: Cross-reference search | TI.com, The TI parts that come up that have the same functionality as the MAXIM/ADI part numbers you have provided are as follows:

MAX4172: INA138 (INA138 data sheet, product information and support | TI.com) and INA139 (INA139 data sheet, product information and support | TI.com).

MAX4173: INA281 (INA281 data sheet, product information and support | TI.com).

MAX4230: TLV9061 (TLV9061 data sheet, product information and support | TI.com).

Best Regards,

Angel

0 Shawn Zhou 11 months ago in reply to Angel Rodriguez de San Miguel Bermudez

Prodigy 30 points

Hello Angel,

Thanks for update, we think INA186 can meet our requirement but we would like to find other low cost solution.

Would you help us check if INA216 can replace with MAX4127?

Please refer to these requirements as below.

1. Vcc > 1.8 V >> INA138/INA139/INA281 cannot meet this.

2. Low Power current sense amplifier (<0.5mA)

3. Bi-directional with high side application

4. Common mode sensing voltage > 6V.

5. Gain 20 to 25 V/V.

6. Enable is nice to have but not mandatory, we could supply the INA & its REF voltage directly on MCU GPIO (ADC_BATT_CTRL).

7.Gain/Offset precision & drift, Bandwidth, slew rate are tbc - INA181 performance is most probably sufficient.

+1 Angel Rodriguez de San Miguel Bermudez 11 months ago in reply to Shawn Zhou

TI__Expert 6810 points

Hi Shawn,

If the supply voltage being limited to 1.8V is a hard requirement then this does only leave INA186 and INA216 (excluding INA190 as it's higher cost/performance part and digital parts) as the available options.

INA216 has a max common-mode spec of 5.5V which would be ruled out according to requirement #4 listed (Vcm > 6V).

It's also worth considering if going for a low-cost uni-directional solution is being offset by having to use two devices instead of one.

It seems to me INA186 is the most suitable device, unless some of the requirements can be compromised such as allowing VS to be a higher value such as 2.7V (e.g. INA181), or being okay with a lower common-mode spec min (e.g. INA216).

Best,

Angel

0 Shawn Zhou 11 months ago in reply to Angel Rodriguez de San Miguel Bermudez

Prodigy 30 points

Hello Angel,

Thanks for your suggestion.

Best Regards

Shawn

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INA186: Use two unidirectional current sense amp to create a bidirectional current sense amp