# What Determines the Maximum Operating Frequency of a Diode?

###### Lanka2022-08-03

Hello, wish you a wonderful day. In this essay, we first pose the following query: what determines the diode's maximum operating frequency? In regards to the solution, the first thing we need to understand is that the junction capacitance and the reverse recovery time of the diode are two distinct concepts. The charging and discharging times of the junction capacitance cannot match the reverse recovery time. You say that, why? Let's start by taking a look at these facts.

Diodes Explained - The basics how diodes work working principle p junction

## Ⅰ. Simple Basics

1. Junction Capacitance

The diode will have parasitic capacitance, which is mainly the junction capacitance, which is a simple diode model.

Figure. 1

2. Reverse Recovery Time

When the voltage abruptly reverses, the diode current in actual applications does not drop to zero right away; instead, a relatively substantial reverse current remains, which must be reduced to 0.1 times the maximum value. The reverse recovery time is time.

## Ⅱ. Facts

Why can the reverse recovery time never be equal to the charge and discharge time of the junction capacitance?

The junction capacitance and reverse recovery time Trr characteristics for diodes are typically provided by the manufacturer. Now let's compare the characteristics of four distinct diode types: Schottky diodes, and ultra-quick recovery diodes.  rapid recovery diodes, and standard diodes

We ensure that the four manufacturers of the four different types of diodes   have the same withstand voltage, packing, and maximum working current in order to make the results more credible. The maximum reverse withstand voltage is 100V, all of the packages are SMA, and the maximum operating current is 1A. The manufacturer chosen here is DIODE Semiconductor.

The models are:

● Schottky diode: B1100-13-F

● Ultra-fast recovery diode: US1B-13-F

● Fast recovery diode: RS1B-13-F

● Ordinary diode: S1B-13-F