Decoupling capacitor placement in PCB Design - Cell-by-Cell Formula Trace

Sample Data

This table shows integrated circuits (ICs) with their power pins, voltage levels, distance to their decoupling capacitors, and capacitor values used for decoupling.

Cell	Value
A1	Component
B1	Pin
C1	Voltage (V)
D1	Distance to Capacitor (mm)
E1	Capacitor Value (uF)
A2	IC1
B2	VCC
C2	3.3
D2	5
E2	0.1
A3	IC2
B3	VCC
C3	5
D3	10
E3	0.01
A4	IC3
B4	VCC
C4	1.8
D4	3
E4	0.1

Formula Trace

IF(D2<=5, "Good placement", "Too far")

Step 1: D2<=5

Step 2: 5<=5

Step 3: IF(TRUE, "Good placement", "Too far")

Cell Reference Map

    A       B       C       D       E
1 |Component|Pin    |Voltage |Distance|Capacitor
  |         |       |(V)     |to Cap  |Value
2 |IC1      |VCC    |3.3     |5      |0.1
3 |IC2      |VCC    |5       |10     |0.01
4 |IC3      |VCC    |1.8     |3      |0.1

Formula references cell D2 (distance for IC1)

The formula checks the distance value in cell D2 to decide if the capacitor placement is good or too far.

Result

    A       B       C       D       E       F
1 |Component|Pin    |Voltage |Distance|Capacitor|Placement
  |         |       |(V)     |to Cap  |Value    |
2 |IC1      |VCC    |3.3     |5      |0.1      |Good placement
3 |IC2      |VCC    |5       |10     |0.01     |Too far
4 |IC3      |VCC    |1.8     |3      |0.1      |Good placement

Placement result shown for IC1, IC2, and IC3 based on distance

The formula result 'Good placement' or 'Too far' is shown in column F for each IC, indicating if the capacitor is placed close enough.

Sheet Trace Quiz - 3 Questions

What does the formula check in cell D2?

A If the voltage is greater than 5 V

B If the capacitor value is 0.1 uF

C If the capacitor distance is less than or equal to 5 mm

D If the pin is VCC

Key Result

IF(condition, value_if_true, value_if_false) returns one of two values based on a logical test.