LP3990 - replacement for LP3985

Robert Komander

Prodigy 200 points

Other Parts Discussed in Thread: LP3990, LP3985

Hi all!

Because "asktexas" incomprehensibly doesn't let ask anything:

have I 2 questions:

1. LP3985 has Cbyp 10nF at PIN4, LP3990 PIN4 is specified as UNCONNECTED, must the Cbyp be removed?

2. What happens if Cout of LP3990 is greater than 1uF, i.e. 10uF?

Thanks
Robert

over 10 years ago

0 Donald Jones over 10 years ago

TI__Mastermind 22610 points

For LP3990SD-x.x/LP3990MF-x.x pin 4 : I will need to get the pin 4 vs bond-wire information from Product Engineering to answer. Hopefully I can get info within a few hours.

As for LP3990 Cout = 10uF, no problem with stabilty, a few 10's of micro-seconds longer to charge up the 10uF at power-on, possible voltage sag on Vin to charge the 10uF for a bit longer time.

0 Donald Jones over 10 years ago

TI__Mastermind 22610 points

For LP3990 Device Pin 4, on both LP3990SD-x.x (WSON) and LP3990MF-x.x (SOT23), there is no internal connection (bond wire) so having Cbyp on this pin will not affect LP3990 operation.

0 Robert Komander over 10 years ago in reply to Donald Jones

Prodigy 200 points

Hi Donald,

thanks, these are good news.

Robert

Power management

Power management forum

LP3990 - replacement for LP3985