Other Parts Discussed in Thread: TINA-TI, ADS1294R,
Tool/software: TINA-TI or Spice Models
Hello Eng. Alex,
It is nice to hear from you.
I have designed a 4 layer PCB with ADS1298 and ADS1294R. The idea was to get 12 lead ECG plus ICG. Given the smallest form factor, I decided to have analogue and digital grounds. Then I divided one of the signal layers in two 3.3V, 5V and some analogue ground in between. Then I had analogue ground plane. My problem was to follow the layout given on the data sheet. It was almost impossible to route the digital and analogue trances with out crossing each other. The other problem was to get the footprints of the ADS129x. Again I chose the NFBGA footprints and a placement cost was really high. That is all over. Now I am planning a new design and I want your feedback assuming 7.5 cm diameter circular PCB board.
1. Do you recommend separate ground (Analogue and digital)? If so does a 0 ohm resister enough to tie them together or should I use a back to back connected diodes?? Where is the possible star point??
2. What is the preferred layout for a 4 layer board??
3. What is the effect of pouring a copper ground plane on the component and bottom layers despite the fact that one of the layers is a ground layer??
4. Is it necessary to have a power plane (3.3 and 5 V)?
Again thank you and looking forward to hear from you!!
Kind regards.
Mes
