Can bypass capacitor be eliminated?

John11513

Other Parts Discussed in Thread: LP2951

Hi,

My customer is designing a 12V to 7.4V converter circuit with LP2951. The datasheet recommends to use a 100pF bypass capacitor across OUT and FEEDBACK pins to maintain stability and low noise especially when external feedback resistor is "high-value". However, they does not have enough pcb space for that capacitor. I am wondering is it possible to eliminate the bypass capacitor? considering their feedback resistor is not "high-value" (51k/10k), and stray capacitance is very low, no more than 1pF.

Thank you!

John

over 9 years ago

0 Michael J Schultis over 9 years ago

TI__Mastermind 24975 points

John,

With low stray capacitance and low feedback resistors you should be fine without it.
Still, I would suggest trying it on the bench if you can.

Best,
Michael

0 John11513 over 9 years ago in reply to Michael J Schultis

TI__Expert 5720 points

Hi Michael,
Thank you for reply. But this is difficult to convince customer. What is the criteria between "low" and "high"? Even with bench test, it cannot cover all part to part variation. So the best way is to provide the loop gain/phase response of the part I think. Can we provide?
Thank you,
John

0 Michael J Schultis over 9 years ago in reply to John11513

TI__Mastermind 24975 points

Answered offline.

Best,
Michael

Power management

Power management forum

Can bypass capacitor be eliminated?