THS4121 Pull-up Resistor

Dan Xiao

Other Parts Discussed in Thread: THS4531, THS4121

Dear TI Support,

I am looking for a fully differential Amplifier to convert bipolar (+/-2.5V) signal from a current sensor (2MHz bandwidth) to differential signal to a 65MHz TI ADC. I found THS4121 and THS4531 could do it. But I am not sure about the pull-up resistor circuit to the power supply. In THS4121 datasheet, it recommends using pull-up resistor to limit the common mode input voltage to V+/V-, as the the sensor's output might be higher than the nominal output 2.5V. Is that circuit applicable to all the fully differential amplifiers (incl. THS4531)?

Tahnks

over 9 years ago

0 Samir Cherian over 9 years ago

TI__Genius 12631 points

Hello Dan,

The level shift circuit is valid for all FDA circuits. Please note that you can always use TINA to simulate your sensors common mode output voltage, desired output common-mode and available head room.

Thanks,

Samir

0 Dan Xiao over 9 years ago in reply to Samir Cherian

Prodigy 110 points

Hi Samir,

My signal nominal range is -2.5 to 2.5V. Occasionally, it goes up to +/-10V. I want to protect the input of FDA. Do you have any typical circuits (better low leakage current) for the input protection? Or there are some FDA with input clamp.

Dan

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THS4121 Pull-up Resistor