# Trace Path Length

### Description

**Trace Path Length** calculates the trace length between two pins of interest.

**Passing Criteria:** \
This check passes if the calculated trace length falls below a specified tolerance

**Reporting Units:** \
CENTIMETERS (cm)

### **Examples**

**Passing Message:** 

{% hint style="success" %}
Trace path length of 0.73cm within acceptable range (0cm to 1cm)
{% endhint %}

**Failing Message:** 

{% hint style="danger" %}
Trace path length of 2.95cm outside acceptable range (0cm to 1cm)
{% endhint %}

### Physics Justification

Minimizing the trace length is important because: 

* **Reduced Parasitic Inductance**: 

  Longer traces introduce **parasitic inductance**, degrading the ability to respond to high-frequency noise. 
* **Improved Noise Filtering**: 

  A short trace allows a capacitor to quickly supply or absorb current, effectively stabilizing the voltage and filtering noise. 
* **Lower Impedance Path**: 

  Shorter traces decrease impedance, ensuring robust and efficient power/signal delivery to the pin. 

#### Helpful Definitions 

* **Parasitic Inductance** \
  The unintended inductance present, which arises from the magnetic field created by current flow and opposes changes in current, especially at high frequencies. It can degrade circuit performance by slowing responses and causing noise.


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