| ??? 05/12/06 16:20 Read: times |
#116107 - What I meant Responding to: ???'s previous message |
Prahlad said:
Do you mean no resistor where the Vcc line crosses two gnd planes? Please expalin this a bit more. The capacitor at output of LM2937 in digital section is C26. In your layout R27 makes sense, because it's used to traverse the gap. I wanted to focuse on another point: We once stated, that the LDOs don't like complex loads at there outputs, and that we should add resistors to the decoupling measures to isolate the LDOs' outputs from this ferrite bead stuff. So, if you connect B5 in the way you do, you will need R27, not only for traversing the gap, but also to provide this isolating series resistance. But if you, in a different layout, want to connect Vcc to AVCC, and you find out, that the series resistance causes too much voltage drop, then you can omit R27, if you connect B5 directly to Vcc pin, means C28 here. Kai |
