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THS4222: Maximum quiescent current

Gerald Sellmair
Prodigy 90 points
Other Parts Discussed in Thread: THS4222

Hi TI community,

sorry to bother you with a most probably stupid question, but I am a bit confused now.

I am using the THS4222 with a +/-5V supply. Looking at the measured quiescent current  I can see approx. 28mA for each supply: i.e. 28mA@+5V and 28mA@-5V.

Having a look at the datasheet I can find "Maximum quiescent current per channel of typ 14mA".

I know that the THS4222 is a dual Opamp so I have 28mA. So does this mean that each supply (+5V and -5V) has to deliver 28mA as I have measured? Or is something wrong with my setup?

Thanks for your help!

Best regards,

Gerald

  • 0
    TI__Genius 15975 points

    Hi Gerald,

    You are measuring correctly quiescent current of 28mA on both the supplies because it is 14mA for each channel. It is just that the +5V supply is sourcing 28mA of current and the -5V is sinking 28mA of current. Hence, you are reading 28mA on each of the supplies. You could also use a DC multimeter of eg. HP3478A to verify the same as to whether you are actually providing a quiescent current of 28mA to the IC.

    Regards,

    Rohit 

  • 0 in reply to Rohit Bhat
    Prodigy 90 points

    Hi Rohit,

    you are perfectly right ... thanks for your hint.

    I was confused because I generate my +/-5V supply by an isolated DC-DC converter. There I was measuring the primary current which of course has to reflect both power lines.

    I was desperately looking for a circuit issue and this made me blind for the most apparent explanation.

    Thanks a lot for your help!!!

    Best regards,

    Gerald