THS4631DGNEVM： About large current operation

Attach the file.

Hello,

Yes the THS4631 should be able to achieve the output current needed here (around 73mA). What is driving your input? What load is the THS4631 driving here?

Best,

Hasan Babiker

Hello, Thank you for the reply.

I'm sorry, Vin was wrong.
The correct value is 1.875VDC (about 62.5mA).
The load is IN + (4pin) of AD8336.

The input is a regulated power supply.

Hi,

is this a test circuit? Or what is the purpose of this strange circuit? Please explain :-)

Kai

Hallo,

This is part of the current measurement circuit.
(This circuit converts current to voltage.)
I am using a regulated power supply for evaluation.

I want to measure a current of 62.5mA, but THS4631 does not work as expected.

I want to know the cause of this.

user_ths4631.TSC

Kai

Thank you for the simulation file.

I also tried the simulation, but the results do not match my test board.
On the test board, the "minus pin" is about 100 mV.

The conditions will change,
If "VG1" is set to 2.4V in the simulation, the "minus pin" will be about 100mV.
This is similar to my test board.

Hello,

Please note the following output swing limitations of the device for 100-ohm load:

Note that these values are for a +/- 5V supply. The output swing for a high temp condition at +/-12V can be limited to +/- 6.5V at the output. Increasing your supplies further should resolve the issue.

Best,

Hasan Babiker  

Thanks for the update, the 200-ohm load helps better explain the swing limitation.

Best,

Hasan Babiker

Hi user,

but why so complicated by using an inverting amplifier? Why not using a non-inverting amplifier and simply amplifying the voltage drop across the 30R shunt?

Kai