• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 50 subscribers
  • Views 667 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

THS4521: Power consumption under saturation condition

antoine caplain
Prodigy 30 points
Part Number: THS4521

Hello,

We use a THS4521in front of an ADC input on this configuration :

Signle ended to differential

Single supply +5V

VOCM is left floating

Gain = 5.36 = R2/R1, with R1 =261 Ohms and R2 = 1400 Ohms

It woks well and I supply is about 2 mA (load = 2.2 KOhms, with sinus CW 10 KHz , level=2.4 Vp on output  for instance) when the amplifier is in linear mode (no saturation).

But when its goes to saturation mode (Vin * Gaion > 2.45 Vp)  the power consumption of the amplifier THS4521 rises to 7 mA  instead of 2 mA.

Could you explain this over-consumption under saturation ?

A standard AOP does not react like that.

best regards

thanks

A.C.

  • 0
    TI__Genius 15975 points
    Hi Antoine,

    It is difficult to explain the over current consumption under saturation condition, as the devices internally become non-linear (which is not very well modeled) for such a scenario. I believe the 7mA seen on the supplies should be representative of the device characteristic under saturation condition as this is normally a slew limited condition as well which results in supply current increase. Have you made sure the supply current returns to 2mA once the saturation/over-drive condition has been removed?

    Best Regards,
    Rohit
  • 0 in reply to Rohit Bhat
    Prodigy 30 points

    Hello Rohit ,

    Thanks for your answer.

    Yes, the supply current becomes normal to 2mA when the saturation has been removed.

    We have 100 parts TH4521 on the board, and it makes the general power supply in over-current condition when saturation (then reset of the board....). So the correction will be to limit the current at the  analog parts level.

    best regards.

    A.C.