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Part Number: LM2902
Hi allWould you mind if we ask LM2902?On our customer's circuit, there is big propagation delay between input and output.We think it is cause of customer's circuit.So, at the first we would like to share the circuit.However these files inculde confidential content.Could let us know your E-mail address?(We would like to send you the file.)Kind regards,Hirotaka Matsumoto
Here is LM2902 (LM324) Tech-Day presentation that should explain the cause and solution.
Regards,Ronald MichallickLinear Applications
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In reply to Ron Michallick:
Ron sanThank you so much for your support and your advice.We would like to confirm one point."This is about 2.0V/(0.5V/us) = 4us. There is also something call "overload recovery" time.This is the time between output at VOL or VOH level (open loop mode) getting back into a linear operation mode (closed loop mode).This accounts for the rest of the 7.2us delay seen."->There is a bit idifference between 4us and 7.2us. We got that "This is about 2.0V/(0.5V/us) = 4us. There is also something call "overload recovery" time. The difference 3.2us, what is the cause? If you have some advice, could you let us know?Kind regards,Hirotaka Matsumoto
In reply to Hirotaka Matsumoto:
This is the most likely cause for overload recovery (aka storage time)
This node can go high quickly, turn off is much slower.
Ron sanThank you very much for your reply!OK, we got it!We would like to confirm one point."from 5V to pin 5"->It seems that 5 pin is 2IN+ or NC.Does it mean NC?Kind regards,Hirotaka Matsumoto
Ron sanWe are sorry to rush you, however could you give us the reply for our last update?"from 5V to pin 5"->It seems that 5 pin is 2IN+ or NC.Does it mean NC?Kind regards,Hirotaka Matsumoto
2IN+ is the pin.
If noninverting input is alway a little positive then the output will be souring a tiny current and output will respond quickly.
Ron sanThank you very much for your reply!Ok, we got it.Kind regards,Hirotaka Matsumoto
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