I currently use LME49720, is there any other opamp I should try? Planning to try either LT1364 or LT1361
post #1726 of 2194
6/7/08 at 1:41pm
|1.) I replaced C72, C74, C75, C43 -->Rubycon MBZ 1000uf 16v|
|C46, 91, 107, 119 -->Rubycon MBZ 1000uf 10V|
|and C16 -->Panasonic FL 680uf 4v...do you think my mod is suitable? any inappropriate? well, i'm poor, those cap i all taken from the mobo and GC...|
|2.) Since you said that the recommended cap ripple value is around 1500mA, but the application design by using Sanyo Oscon SVP 330uf 16v has a rated RMS ripple current 4720mA as well, how you going to explain it?|
|3.)In this case the input ripple voltage would be 140 mV and the RMS ripple current would be 1.5 A. The maximum voltage across the input capacitors would be VIN max plus delta VIN/2. The chosen bulk and bypass capacitors are each rated for 25 V and the combined ripple current capacity is greater than 3 A, both providing ample margin. It is very important that the maximum ratings for voltage and current are not exceeded under any circumstance.
I think the ripple current you said was came from here, rite? Ok, if the RMS ripple current is 1500mA, that means we suppose should use the cap that can handle at least or above this current rating? is that any wrong?
|The ESR is important because along with the inductor current it determines the amount of output ripple voltage.|
|Consider the relationship between the desired closed loop crossover frequency of the design and LC corner frequency of the output filter. In general, it is desirable to keep the closed loop crossover frequency at less than 1/5 of the switching frequency.|
|In Figure 28, the TPS54356 shown with a single 100-µF
6-V POSCAP as the output filter capacitor.
|Calculating the RMS ripple current in the output capacitor using equation 16 yields 156 mA. The POSCAP 6TPC100M capacitor selected is rated for 1700 mA.|
|In Figure 29, the TPS54356 shown with two 180-µF 4-V special polymer dielectric output filter capacitors(C2 and C5). The RMS ripple current in the output capacitor is the same as before. The selected capacitors are each 3.3 A.|
|The special polymer electrolytic capacitors used in this design require that the closed loop crossover frequency be lowered due to the significantly lower ESR of this type of capacitor.|
|bro, comment on it, just give any suggestion or correction or even criticism, i will please to hear it, thanks...|
If you don't want to replace the power filter capacitor with the BG 16v 2200uF, what would be some good alternatives?
Well, i use Panasonic Low ESR 680uf 4v solid cap, work perfectly...
Asus is well-known for using fake brands of caps and even fake caps. Seen this only too many times...
The reason why Panny FL is not into Panny caps list is clearly simple. They did not made them. It is that simple. I can show you many examples, but this is a X-Fi thread, not fake caps thread
Yes, I used Oscon as C177 before, and quess what. The voltage is nowhere as clean, as with the Panny FM 470uF 16V or the Samxon GC 1000uF 6.3V ... spikes are measured with scope, of course. DMM is useless for measuring at mainbords, because in case of AC voltage or DC with spikes/noise it always only show the effective average, where you are most interesed about the noise, spikes and/or the highest spike to know, what is the absolute max voltage on the cap, so what voltage cap you can use there. That is why I in my thread took the time and measure ALL the caps on X-Fi for their max voltages
dammit my x-fi doesn't work when i install my Radeon video card. is there some kind of weird incompatibility between the SB0460 and certain motherboard/video card combos?