After power up swithing frequency slowly decrease, then stop. After few minutes it goes up. I think is thermal unstability.
What's the frequency variation like? How long before it settles?
Have you measured it again after it's been loaded down?
Have you further tried to narrow down the offensive part by say.. applying cold spray.. or hot air?
Something so simple as a better selection of input pair transitors (lower parasitics) could possibly help minimize this.. if they're to blame, even epoxying them together perhaps. Find the guilty party first though.
Might check out the components in the feedback loop as well.
Neat problem 🙂
Have you measured it again after it's been loaded down?
Have you further tried to narrow down the offensive part by say.. applying cold spray.. or hot air?
Something so simple as a better selection of input pair transitors (lower parasitics) could possibly help minimize this.. if they're to blame, even epoxying them together perhaps. Find the guilty party first though.
Might check out the components in the feedback loop as well.
Neat problem 🙂
Hi. I try worm air upon a pcb - result: the swithing freq. is increase.
Then i glue together transistors in diferential amplifier all work fine. The freq is changing from 350 khz to 348khZ, then increasing to 352khz, so i have +/- 5 khz unbalance. Its normal or not. How is fixed in original UcD modeles from HYPEX?
Best regards.
Then i glue together transistors in diferential amplifier all work fine. The freq is changing from 350 khz to 348khZ, then increasing to 352khz, so i have +/- 5 khz unbalance. Its normal or not. How is fixed in original UcD modeles from HYPEX?
Best regards.
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