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THS6214: THS6214 output bias issue

user4467016
Prodigy 10 points
Part Number: THS6214

Hi Team,

      I have tested TI THS6214, the power supply is 12V, and I found we have a 6V bias on Pin20 and Pin17, may i know the reason why we have a bias ? And what is the maximum voltage tolerance of Pin20 and Pin17? Any comments will be appreciated!  Thanks.

Best,

He Jia

  • 0
    TI__Genius 12631 points

    Hello Jia,

     The resistive divider formed by R7 and R3 create a common-mode bias of 6V. The common-mode gain of the circuit is 1V/V so that common-mode voltage is passed to the output pins. This is briefly explained on page 24 of the datasheet.

    On page 8 of the datasheet the typical output swing of the THS6214 is specified as +/-4.9V for an Rload =  50 ohms on each output. Since you are using single-sided supplies in your application, the output swing limit on the pins is 1.1V to 10.9V. Hope this is clear.

    -Samir

  • 0 in reply to Samir Cherian
    Prodigy 80 points

    1、 AS in figure，I add a 1.5V peak 2MHz frequency differential signal to pin 1&2， output is 2 Ω load，how about the output  waveform of pin17&20 in 1us to 1 mins, why？

    2、 What is the state about Pin23&24, the datasheet is 100% offset, but the actual test is closed state, could you help explain why？

    3、 Any overtemperature protect inside THS6214?

  • 0 in reply to Yuan Legend
    TI__Genius 12631 points
    Hello Yuan,
    Q1. I am not sure what your Q1 means. However, if you have a differential input with 1.5Vpeak = 3Vpp input into an amplifier in a gain of (1+2200/165) = 35, the output is a 105Vpp output signal. The output of the amplifier will therefore be saturated. You also have a 2 ohm load at the output of two 98 ohm resistors...that itself is an attenuation of around 1/99.

    Q2. Based on your circuit it looks like the Bias pins have 0,0 on them which is full-bias mode. Again, I am not sure what you are asking over here.

    Q3. Most of our amplifiers have thermal protection when the die temperature is in excess of 150C. I am not sure if the THS6214 has thermal protection; I will have to check. Based on your circuits and comments I don't think you have an overtemp issue.

    -Samir