| ??? 03/16/06 16:02 Read: times |
#112314 - Some hints Responding to: ???'s previous message |
Prahlad said:
I added the 6 hole ferrite that i use with my micro supplies RS order code 260-6818 Type 7427501 Wurth make. It has 800E impedence at 100MHz & 598E at 25MHz. The bead can be seen in the CD4060 gnd plane and the 100E resistor crossing the bridge. Is it ok? Perfectly! Prahlad said:
I conencted second cap to CD4060 supply line in analog section to form a PI filter is the connection ok? What value this cap should be for optimum results? Connection is alright. For optimum results caps of a pi-filter should be identical. So, you need to add a 100nF. Prahlad said:
I also connected a resistor in the oscillator output [signal] line where it crosses the bridge. What value this resistor should be? A cap is also added to signal line after the resistor in analog plane to form the pi filter what value this cap should be? Make an 1k resistor cross the gap and use two 47n caps at both sides of the gap. Prahlad said:
Reinforced the top and bottom layers gnd with lots of vias. Well done. But some of them are a bit too close to other solder pads. For instance at C11. A few more points: - C11 is an electrolytic cap. Your schematic shows a biplor cap though. - I have made a serious drawing mistake: At the active filter stages all the first caps must be connected to output of according OPamps of course, not to ground! Wondered, that nobody has noticed this in the meantime... I appologize! - Due to the power supply filters in each supply line of OPamp, there's no need to route the +15V and -15V lines from a star point to each OPamp! You can save a lot of PCB area by this and use it for the ground planes. Your board looks very nice now, like a professional one! Good luck, Kai |
