An analog delay line is a network of electrical components connected in cascade [dubious – discuss], where each individual element creates a time difference between its input and output. It operates on analog signals whose amplitude varies continuously.

Any logic gate has a propagation delay and can be used as a delay line. The difficult part is building a delay line that can be set precisely to a specific delay period that remains consistent over variations in process, temperature, and voltage.

Modern analog delay lines come in in- tegrated-circuit form and are commonly known as CTD (Charge Transfer Device) or bucket-brigade delay lines.

These flexible devices can be configured as traditional delay lines, as pulse width modulators or even as programmable oscillators. A variety of configurations are illustrated, the various features of which cover most applications.

This application note compares each programmable delay line and non-programmable delay line to help customers choose the appropriate device for their application.