FEDEVEL
Platform forum

, 06-23-2026, 05:14 AM

I really need to know the advantages and disadvantages of each via placement method, and which one is the correct approach.

, 06-23-2026, 05:23 AM

🤖 In the meantime, here’s a response from the [FEDEVEL AI HW Assistant]().
It helps to find relevant resources for your question, but it may make mistakes as it’s still in early development.

This is the response from the AI Assistant:
Here's the breakdown of via placement methods for decoupling capacitors based on practical PCB design insights from our video knowledge base:

**1. Single Via Per Pin (Power/Ground)**
- *Advantages*:
- Ensures clean return current paths (critical for high-speed signals)
- Prevents shared impedance between multiple components
- Reduces ground/power plane noise coupling
[Example where shared ground vias create return path issues](https://www.youtube.com/watch?v=v8seW2BZits&t=246)

- *Disadvantages*:
- Consumes more board space
- Requires careful planning in dense layouts

**2. Multiple Vias for High Current**
- *Advantages*:
- Reduces loop inductance (critical for power integrity)
- Handles higher current capacity
- Balances current distribution (equal vias on both power/ground sides)
[Example showing via symmetry for capacitor connections](https://www.youtube.com/watch?v=v8seW2BZits&t=819)

- *Disadvantages*:
- Increases manufacturing complexity
- Requires more precise thermal management

**3. Shared Vias (Multiple Pins to One Via)**
- *Advantages*:
- Saves board space
- Simplifies routing in constrained areas

- *Disadvantages*:
- Creates shared impedance paths (noise coupling risk)
- Impedes return current flow for high-speed signals
- Can create resonance issues with multiple capacitors
[Case where shared via causes power distribution challenges](https://www.youtube.com/watch?v=vGq4uUtr6Uo&t=780)

**4.

, 06-23-2026, 05:23 AM

Direct Layer Connection (No Vias)**
- *Advantages*:
- Lowest inductance path (ideal for high-frequency decoupling)
- Best performance when capacitors/pins are on same layer
[Simulation showing superior performance of direct connections](https://www.youtube.com/watch?v=XumNc480qYo&t=1)

- *Disadvantages*:
- Not always physically possible in multi-layer designs
- Limits routing flexibility

**Correct Approach:**
1. **Priority Order**:
- First choice: Direct same-layer connection without vias
- Second choice: Dedicated vias per capacitor pin (1+ vias per power/ground)
- Last resort: Shared vias with star connections (never daisy-chained)

2. **Key Implementation Rules**:
- Place vias *closer to capacitor pads* than to IC pins (reduces loop area)
- Use matched via counts for power/ground pairs (symmetry matters)
- For BGAs/power-hungry ICs: Multiple vias with >20um annular rings for reliability
[Via inductance analysis in decoupling context](https://www.youtube.com/watch?v=ARwBwHZESOY&t=2669)

**Surprising Finding from Simulations**:
Capacitor *placement proximity* to IC has 3-5X greater impact on impedance than via arrangement details. A poorly placed capacitor with perfect vias often underperforms a well-placed capacitor with mediocre vias. [Impedance comparison across layouts](https://www.youtube.com/watch?v=XumNc480qYo&t=1377)

When space forces compromises:
- Sacrifice via count before compromising placement distance
- Use 0402/0201 caps with 1 via each rather than larger caps with multiple vias

You can continue chatting with the AI Assistant here:
https://fedevel.com/hw-assistant

Robert Feranec , 06-23-2026, 06:45 AM

In my opinion if you can have direct connection on 1 layer between decoupling cap pad and IC pad (that is what you have on your pictures), then for standard boards exact placement of via may not be that important. Watch my video suggested by AI: https://youtube.com/watch?v=XumNc480qYo&start=1

Skoomadentist , 06-23-2026, 09:44 AM

I had a sort of epiphany on that when I realized that the loop inductance between IC Vcc and IC gnd is what matters, not physical distance to board Vcc. So ideally for not-bga you want to put the cap directly between IC Vcc and gnd pins and where the power route comes from is not important because it has more inductance than the capacitor anyway. Likewise any gnd via for the cap and other distance from IC gnd to cap gnd gets directly added to the effective loop inductance.