Introduction to Circuit Design

Term

Definition

Amplitude

The instantaneous voltage of a waveform. Often used to mean maximum amplitude, or peak voltage, or a pulse.

Boolean Expression

An algebraic expression made up of Boolean variables and operators, such as AND (-), OR (+), or NOT (-). Also referred to as Boolean function or a logic function.

Clocked D Flip-Flop

Type of flip-flop in which the D (data) input is the synchronous input.

Digital Waveform

A series of logic 1s and 0s plotted as a function of time.

Dual In-Line Package (DIP)

One style of integrated circuit package which has two rows of lead.

Duty Cycle (DC)

Fraction of the total period that a digital waveform is in the HIGH state. DC = th/T (often expressed as a percentage: %DC = th/Tx100%).

Falling Edge

The part of a pulse where the logic level is in transition from a HIGH to a LOW.

Flip-Flop

A sequential circuit based on a latch whose output changes when its CLOCK input receives a pulse.

Frequency

The number of cycles per unit time of a periodic waveform.

Hertz (Hz)

Unit of frequency. One hertz equals one cycle per second.

Integrated Circuit (IC)

An electronic circuit having many components, such as transistors, diodes, resistors, and capacitors, in a single package.

Inverter

Also called a NOT gate or an inverting buffer. A logic gate that changes its input logic level to the opposite state.

Logic Diagram

A diagram, similar to a schematic, showing the connection of logic gates.

Oscilloscope

A piece of test equipment used to view and measure a variety of different waveforms.

Period

The amount of time required for one complete cycle of a periodic event or waveform.

Propagation Delays (tPLH/tPHL)

Delay from the time a signal is applied to the time when the output makes its change.

Schematic Entry

A technique of entering CPLD design information by using a CAD (computer aided design) tool to draw a logic circuit as a