I2S

Overview

The "I2S" interface format is "I squared S" and is also known as "Inter-IC Sound" or "Integrated Interchip Sound." In some cases; limitations in the text formatting can require it to appear as "I2S." The primary application of this interface is to connect digital audio IC's located on the same printed circuit board.

Basics

Once the digital information is generated by the AD converter; it must be transmitted to the next device for storage or processing. Internal to the AD converter system; the I2S format is commonly used to connect the AD converter IC to a digital audio interface IC; and typically consists of three signals:

1. The "Bit Clock" which has one cycle for each "bit" in the serial data output of the AD converter.
2. The "Word Clock" which is at the sample frequency, and each half cycle is used to define whether the serial data is the left channel or right channel data (most contemporary converters are "stereo" two channel units). Sometimes referred to as "Left-Right Clock."
3. The "Serial Data" which is the digital code containing each sample's voltage level information.

This format is not intended for (external) transmission between digital audio devices and is subject to the same jitter and noise considerations as any other high frequency interface. Please see bit clock and AES for more details.