Small Footprint Square Wave Oscillator

This is a compact square wave oscillator that operates at a 50% duty cycle, with a variable frequency ranging from 10 kHz to 30 MHz. The frequency range can be extended to 1 kHz by substituting a 1 MΩ resistor for the 100 kΩ resistor in R6. The schematic presented drives the square wave directly into a 50 Ω load, utilizing five parallel 74AC04 CMOS inverters, which collectively provide a maximum output current of 120 mA.

The described square wave oscillator circuit is designed for applications requiring a stable frequency source with minimal footprint. The oscillator operates by generating a square wave signal with a 50% duty cycle, making it suitable for various digital and analog applications. The frequency can be adjusted within the specified range, allowing flexibility in different circuit designs.

The choice of using a 74AC04 CMOS inverter ensures low power consumption while providing high-speed switching capabilities. The parallel configuration of five inverters effectively increases the output drive capability, allowing the circuit to handle a load of 50 Ω without significant signal degradation.

For applications that require a lower frequency output, the modification of R6 to a 1 MΩ resistor allows the oscillator to generate frequencies as low as 1 kHz. This adaptability enhances the versatility of the circuit, making it suitable for a wider range of applications.

It is important to note that while the circuit functions correctly without parallelizing resistors between the gate outputs, the inclusion of such resistors is a common practice to ensure equal loading and prevent potential issues related to output impedance mismatches. However, the current configuration has been reported to work effectively in practice, demonstrating the robustness of the design.

Overall, this square wave oscillator circuit is a reliable and efficient solution for generating high-frequency signals in compact electronic designs.This is a small footprint 50% duty cycle square wave oscillator with variable frequency from 10kHz to 30MHz. The frequency range can be extended to 1kHz by using 1M instead of 100k for R6. The sheet presented here drives the square wave directly into 50Ohm; the output stage uses 5 parallel 74AC04 CMOS in

verters which sums up to a total of 120mA max. (Some people may shout at me here because I did not use parallelizing resistors between the gate outputs. Oh well, but it works fine for me this way. ) 🔗 External reference