| ??? 02/16/05 05:02 Read: times |
#87606 - Ground bounce Responding to: ???'s previous message |
Christian said:
why? is it because of the fast setup time of 6ns is too much for a wirewrap? what if i use a breadboard, i was thinking in doing something similar. Is the signal afected too much? No, it's nothing to do with setup time, but these fast digital chips suffer from heavy ground bounce! Whenever the gate toggles supply current spikes are the result, which can totally erode noise margin, when not running over ground traces providing very low inductivity. These fast digital chips demand the use of a solid ground plane (if not even a multilayer baord!) and proper power supply decoupling with each chip. Similar uncomfortable are 74ACMOS chips. With a breadboard design there's a big chance, that ground bounce will totally erode signal integrity. Kai |
| Topic | Author | Date |
| Problem getting 8051 chip to work | 01/01/70 00:00 | |
| tie ~EA pin to Vcc | 01/01/70 00:00 | |
| tie Vpp/~EA pin to Vcc | 01/01/70 00:00 | |
| to connect or not? | 01/01/70 00:00 | |
| conbnect | 01/01/70 00:00 | |
| If it helps.... | 01/01/70 00:00 | |
| Reset Capacitor | 01/01/70 00:00 | |
| connect | 01/01/70 00:00 | |
| T89C51RD2 | 01/01/70 00:00 | |
| This device is ISP | 01/01/70 00:00 | |
| VCC and GND? | 01/01/70 00:00 | |
| I think you do not load | 01/01/70 00:00 | |
| Series resistor for LED? | 01/01/70 00:00 | |
| 74F14 | 01/01/70 00:00 | |
| give me +1 too | 01/01/70 00:00 | |
| done | 01/01/70 00:00 | |
| Sorry | 01/01/70 00:00 | |
| LED Polarity | 01/01/70 00:00 | |
| Does not seem to be the cause | 01/01/70 00:00 | |
| Ouch! | 01/01/70 00:00 | |
| FAST-TTL and breadboarded design | 01/01/70 00:00 | |
| Ground bounce | 01/01/70 00:00 | |
| Bad news 74F =( | 01/01/70 00:00 | |
| HCT? | 01/01/70 00:00 | |
| LS, HCT and maybe AHCT | 01/01/70 00:00 | |
| Got it | 01/01/70 00:00 | |
| wire wrap and breadboards | 01/01/70 00:00 | |
| I use protoboard | 01/01/70 00:00 | |
| the problem with that is | 01/01/70 00:00 | |
| Thanks | 01/01/70 00:00 | |
| Why do you want to use 74F chips? | 01/01/70 00:00 | |
well... | 01/01/70 00:00 | |
| maybe you are still in ISP mode? | 01/01/70 00:00 | |
| 1st things 1st please | 01/01/70 00:00 | |
| Thanks | 01/01/70 00:00 | |
| bounce on non PCB | 01/01/70 00:00 | |
| Analytical thinking | 01/01/70 00:00 |