The default I2C address is 0x4C.

Power Pins

• VIN - this is the power pin. It can be powered with 3.3 to 5VDC, however, the data lines are 3.3V logic only.
• GND - common ground for power and logic

I2S Pins

• WSEL (Word Select or Left/Right Clock) - this is the pin that tells the DAC when the data is for the left channel and when it's for the right channel.
• DIN (Data In) - This is the pin that has the actual data coming in, both left and right data are sent on this pin, the WSEL pin indicates when left or right is being transmitted.
• BCK (Bit Clock) - This is the pin that tells the amplifier when to read data on the data pin.
• MCK (Main clock, optional) - This pin is optional for the PCM5122 because it will auto-generate the main clock internally from BCK.

Audio Output

The audio output from this breakout is line-level. It is not AC-coupled because it is centered on ground. You can plug it into anything that is either AC coupled or has the same ground reference.

• Lout - This is the left channel audio output
• Rout - This is the right channel audio output
• GND - This is a clean analog ground signal for the audio output
• 3.5mm output jack - This is the onboard output audio jack. Note that it cannot drive headphones - the output is for no less than 1K ohm loads!

Control Mode Selection

The PCM5122 can be controlled via hardware, I2C or SPI. The control mode is determined by pulling pins MOD1 and MOD2 high or low. By default, hardware mode is enabled with both MOD1 and MOD2 open. The table below shows the possible combinations to enable the different modes.

Note that in SPI mode, the MOD2 pin is also the CS pin, so it does not need to be pulled specifically high or low.

Hardware Control Pins

These pins can be used in hardware control mode (not I2C/SPI config mode) to affect the DAC.

• DEEM - This is the de-emphasis pin for 44.1khz audio. By default it is off.
• FILT - This is the filter pin. You can change the filter from normal to low-latency by pulling the pin high.
• FMT - This is the format pin. You can change the format from I2S to Left justified by pulling the pin high.
• AGN - This is the analog gain selector. When the pin is low, the gain is set to 0 dB. When it is pulled high, the gain is set to -6 dB.
• ATT0, ATT1 (SCL) and ATT2 (SDA) - These are the gain and attenuation control pins. Note that ATT1 is labeled SCL on the board silk and ATT2 is labeled SDA on the board silk. They set the output level by being pulled high or low. The table below shows the possible combinations to set the different gain levels:

The MUTE pin can be used to mute the DAC in all modes.

• MUTE - This is the mute pin. You can pull this pin low to set the outputs to ground.

I2C Control Pins

These pins are used to control the DAC via I2C.

• SDA - the I2C data pin, connect to your microcontroller's I2C data line.
• SCL - the I2C clock pin, connect to your microcontroller's I2C clock line.

I2C Address Pins

On the front of the board are two address pins, labeled A1 and A2. These pins allow you to change the I2C address to connect multiple boards by connecting them to VIN.

The default I2C address is 0x4C. The other address options can be calculated by "adding" the A1/A2 to the base of 0x4C.

A1 sets the lowest bit with a value of 1 and A2 sets the next bit with a value of 2. The final address is 0x4C + A2 + A1 which would be 0x4F.


If only A1 is pulled high, the address is 0x4C + 1 = 0x4D


If only A2 is pulled high, the address is 0x4C + 2 = 0x4E

The table below shows all possible addresses, and whether the pin(s) should be high or low.

SPI Control Pins

These pins are used to control the DAC via SPI.

• A1 (MISO) - Labeled A1 on the board silk, this is the SPI Microcontroller In Serial Out pin.
• SDA (MOSI) - Labeled SDA on the board silk, this is the SPI Microcontroller Out Serial In pin.
• SCL (SCK) - Labeled SCL on the board silk, this is the SPI clock input pin.
• MOD2 (CS) - Labeled MOD2 on the board silk, this is the chip select pin.

Clock Direction Jumper

• CLK Dir Set - On the back of the board is the I2S clock mode jumper. By default, it is open and expects a clock input from your microcontroller (secondary mode). When soldered closed, it sets the pin high and generates its own clock with a main clock source (primary mode).