# ANSI three-input AND gate

Canonical URL: https://eloragrid.ai/symbols/ansi-three-input-and-gate
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: AND3
Drawing use: Schematic
Reference families: IEEE / ANSI, Manufacturer

## Symbol convention

Convention: IEEE / ANSI
Form: D-shaped AND outline with three inputs
Distinctive-shape form as used in IEEE/ANSI-style schematics and manufacturer data books. Independent educational drawing; exact standard geometry and compliance are not asserted. The counterpart is the matching functional concept; no equivalence of every detailed standard graphic is asserted.
Related representation: [AND gate](https://eloragrid.ai/symbols/logic-and-gate)

D-shaped AND outline with three input leads; the output is high only when all three inputs are high.

## In plain English

### What does ANSI three-input AND gate mean?

The three-input AND keeps the familiar flat-backed D outline and simply adds a third input lead on the flat side. All three inputs must be at logic 1 in positive logic for the output to be at logic 1. Packages such as triple three-input AND devices provide this function directly.

### A simple example

Drafters use the wider gate rather than cascading two-input gates when the function is a single permissive with three conditions, such as guard closed, pressure healthy and mode selected. A single symbol keeps the logic readable and avoids implying an intermediate signal that does not exist.

### What the drawings help you do

The outline does not show whether an unused input is tied high when a three-input part is used for two signals. Unused inputs on the physical device need a defined level shown on the schematic.

### This particular reference

D-shaped AND outline with three input leads; the output is high only when all three inputs are high. A two-input AND followed by another AND produces the same logic but implies an intermediate net.

### Terms

- Signal: Electrical information passed between devices, rather than necessarily the main power supply.
- Schematic: A drawing showing function and connections rather than physical appearance.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [SNx4HC11 triple 3-input AND gates](https://www.ti.com/lit/ds/symlink/sn74hc11.pdf)


## What it represents

The three-input AND keeps the familiar flat-backed D outline and simply adds a third input lead on the flat side. All three inputs must be at logic 1 in positive logic for the output to be at logic 1. Packages such as triple three-input AND devices provide this function directly.
Drafters use the wider gate rather than cascading two-input gates when the function is a single permissive with three conditions, such as guard closed, pressure healthy and mode selected. A single symbol keeps the logic readable and avoids implying an intermediate signal that does not exist.
The outline does not show whether an unused input is tied high when a three-input part is used for two signals. Unused inputs on the physical device need a defined level shown on the schematic.

## How to read it

- Count the input leads; a third input is easy to overlook where leads are closely spaced.
- Check unused inputs are tied to a defined level.

## Information to show or reference

- Space the three inputs evenly along the flat side.
- Label each permissive signal.
- Show tie-offs for unused inputs on multi-input packages.

## Important distinction

A two-input AND followed by another AND produces the same logic but implies an intermediate net.

## Facts

- Inputs: Three
- Example device family: Triple three-input AND packages
- Artwork scope: Original educational illustration; consult the applicable standard and the selected device documentation for the exact graphic

## Public references

- [SNx4HC11 triple 3-input AND gates](https://www.ti.com/lit/ds/symlink/sn74hc11.pdf) — Texas Instruments. Manufacturer documentation for triple three-input AND gates.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.