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INA826: INA826 about the current and the temperature issue

Mickey Zhang
Genius 12080 points
Part Number: INA826


Hi Team,

The customer is using INA826. He powers by +/-14V. The GAIN is set 1 and VREF is  2.5V.

Now the customer make three tests:

1. Please check the Fig 1 schematic.  GAIN is 1. R35 is not connected. The max current of IaccX is +/-40mA. Vbias is 2.5V. There are 3 boards.

At room temperature everything is fine. When the temperature reaches 90 degrees C, the total power supply current of the system  increases

from 110mA to 480mA.

The temperature of the 3  INA826 devices is higher than other areas of the board. Finally, the circuit start and stop frequently.

2. Then the customer removes the 3 INA826 devices, the total power supply current of the system remains the same from 20℃～150℃.

3. Please check the Fig 2 schematic. A 0.5mA current is input to the 4 pin. GAIN is 1. R58 is not connected.  There are also 3 boards.

On these 3 boards, When the temperature reaches 90 degrees C, everything is fine.

 I think The  Fig 1 schematic. I suggest the customer he may solder the 3 INA826 devices of the Fig 2 schematic to the boards of the Fig 1 schematic.

But now he cannot do this since he needs to get the  INA826 devices to the factory to weld.

Now the customer would like to replace INA826.

Q1: Can you recommend a suitable IC to replace INA826? Is there a pin to pin replacement IC ?

Q2: For the customer's issue, can you give me some solutions?

Best Wishes,
Mickey Zhang
Asia Customer Support Center
Texas Instruments

  • 0
    TI__Genius 12080 points
    Hi Team,

    Is there anyone see my issues? The customer is waiting for my reply.
  • 0 in reply to Mickey Zhang
    TI__Guru 68931 points

    Mickey,

    It is very difficult to follow the issue you describe especially since you show only partial schematics. To be able to assist you, we will need at least full schematic around INA826 showing output loading since the concern is excessive current (you do not show any load). I do not see how INA826 could draw anywhere close to 110mA let alone 480mA unless you refer to the current of the entire system and if so how can I comment on the system without seeing it. In point 3, you state 0.5mA input current is applied to pin 4 in Fig 2 but without shunt resistor present INA826 cannot sink such current since its input has high impedance. Please rewrite you questions clearly stating what the problem is and show full schematic that goes together with each question.