Why power integrity ensures reliable operation in PCB Design - Formula Trace Breakdown

Sample Data

This data shows components on a PCB, their power supply voltage, voltage drop due to power integrity issues, and the voltage actually received by each component.

Cell	Value
A1	Component
B1	Power Supply Voltage (V)
C1	Voltage Drop (V)
D1	Voltage at Component (V)
A2	CPU
B2	5.0
C2	0.3
D2	4.7
A3	Memory
B3	5.0
C3	0.1
D3	4.9
A4	Sensor
B4	5.0
C4	0.05
D4	4.95

Formula Trace

D2 = B2 - C2 D3 = B3 - C3 D4 = B4 - C4

Step 1: D2 = 5.0 - 0.3

Step 2: D3 = 5.0 - 0.1

Step 3: D4 = 5.0 - 0.05

Cell Reference Map

    A       B       C       D
1 Component Power   Voltage Voltage
           Supply  Drop    at
           Voltage         Component
2 CPU       5.0     0.3     ->
3 Memory    5.0     0.1     ->
4 Sensor    5.0     0.05    ->

Cells B2, C2, B3, C3, B4, and C4 provide input voltages and voltage drops used to calculate the voltage at each component in column D.

Result

    A       B       C       D
1 Component Power   Voltage Voltage
           Supply  Drop    at
           Voltage         Component
2 CPU       5.0     0.3     4.7
3 Memory    5.0     0.1     4.9
4 Sensor    5.0     0.05    4.95

The final voltage at each component is shown in column D after subtracting voltage drops. This shows how power integrity affects the voltage each component receives.

Sheet Trace Quiz - 3 Questions

What does the value in cell D2 represent?

A Voltage drop at CPU

B Power supply voltage

C Voltage at CPU after voltage drop

D Current through CPU

Key Result

Voltage at component = Power supply voltage - Voltage drop due to power integrity