• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 48 subscribers
  • Views 300 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.

PGA280: Input waveform range

Kyle Villano
Prodigy 10 points
Part Number: PGA280

Hi, I was just wondering if inputting a 20Vpp waveform into this PGA with a +/- 15V supply could possibly be causing damage to it. I am seeing some issues with slew rate (chip is throwing 0x18 Input Clamp Active error)  when inputting square waves at around 16Vpp and higher. Looks like here that an input clamp is being activate which is pulling current from the input waveform and is causing distortions/long settling times. The datasheet for this part states that the input range can be within +/- 15.5V, so I just wanted to make sure I wasn't harming the part in doing this testing. Thanks!

  • 0
    TI__Expert 6460 points
    Hi Kyle,
    The datasheet warning for the input clamp diodes indicates that with inputs slewing faster than the internal amplifiers, an increase in input bias current will be observed. While that increase in bias current may affect the measurement, as long as that bias current is kept below the 10mA absolute maximum specification for input current the PGA shouldn't be damaged. Current limiting could be accomplished by adding series resistors in-line with both PGA inputs. Alternatively, you might be able to use the input current buffers to improve settling time if you can synchronize their activation to your square wave edges.

    Do keep in mind that although the inputs can go up to 0.5V beyond the VSP and VSN supplies without permanent damage, linear operation is only specified for input voltages between VSN+2.5V to VSP-2.5V, or ±12.5V on ±15V supplies.
  • 0 in reply to Alex Davis
    TI__Genius 11135 points
    Kyle

    We haven't heard back from you so we assume this answered your question. If you need additional help just post another reply below.

    Thanks
    Dennis