OPA2380: Auto-zero circuit oscillator

David Bristow

Part Number: OPA2380
Other Parts Discussed in Thread: OPA380

Does the OPA2380 have one auto-zero circuit oscillator for both amplifiers or does it have separate oscillators for the 2 amplifiers?

over 6 years ago

0 Jacob Freet over 6 years ago

TI__Expert 8540 points

Hi David,

Each amplifier has it's own separate circuit.

Regards,

0 David Bristow over 6 years ago in reply to Jacob Freet

Prodigy 60 points

How tightly controlled are the oscillators? Could beating between the two oscillators be a problem? Our OPA380 test circuit shows a spike around 9kHz which we think is the autozero oscillator. We are worried the beat frequency might be in our frequency band of interest.

0 Micah B Brouwer over 6 years ago in reply to David Bristow

TI__Intellectual 1910 points

Hey David,

The zero correction occurs at about a 10 kHz rate so the spike you see is probably from the auto-zero amplifier, but there is internal filtering that should limit the fundamental noise energy at that frequency. What is the magnitude of the spike that you are observing? I doubt that any potential beat frequency would be greater than the noise floor of the system, and that could be determined with some calculation.

0 Micah B Brouwer over 6 years ago in reply to Micah B Brouwer

TI__Intellectual 1910 points

Hey David,

Are there any further questions? If not, I'll close this thread.

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OPA2380: Auto-zero circuit oscillator