Adafruit
Adafruit PCM5122 I2S DAC with Line Level Output - HW, I2C or SPI
· MPN: ADA6421
The Adafruit PCM5122 I2S DAC delivers excellent stereo line-level audio with 112dB SNR and -93dB THD. Out of the box it works in hardware mode — just pipe I2...
The Adafruit PCM5122 I2S DAC delivers excellent stereo line-level audio with 112dB SNR and -93dB THD. Out of the box it works in hardware mode — just pipe I2S audio in with no MCLK or configuration needed. For advanced control, switch to I2C or SPI mode to access software volume, EQ, filtering, and gain settings.
The PCM5122 accepts 16, 24, or 32-bit audio and automatically determines the correct format from the WSEL/BCLK ratio. It generates its own master clock internally, so no MCLK connection is required. Two MODE pins select between hardware-only, I2C, or SPI configuration. Audio output is line-level through a 3.5mm jack (plus breakout pads), centred on ground and not AC-coupled.
Key Features
- 112dB SNR, -93dB THD – Excellent stereo audio quality from the PCM5122 chip
- I2S Input – Just BCLK, WSEL, and DIN (3.3V logic) — no MCLK needed
- Three Operating Modes – Hardware (default, zero-config), I2C, or SPI via MODE pins
- 16/24/32-bit Audio – Automatically detects bit depth from clock ratio
- 3.5mm Line-Level Output – Plus breakout pads for direct wiring
- 3–5V Power – Wide supply voltage range
- I2S or Left-Justified – Toggle the Format pin to switch modes
Hardware Mode Controls
- Filter – Normal or low-latency (pull high)
- Mute – Pull low to set outputs to ground
- De-emphasis – For 44.1kHz audio (off by default)
- 3× ATT Gain Pins – Adjustable gain from -6dB to +15dB (see datasheet Table 3)
I2C/SPI Mode Controls
In I2C or SPI configuration mode, gain/volume, filtering, and de-emphasis are controlled via digital register commands. The hardware Mute pin still functions as expected.
Ideal For
- High-fidelity audio output from ESP32, RP2350, Raspberry Pi, and other I2S-capable boards
- Projects requiring software-controlled volume, EQ, or gain adjustment
- Audio prototyping on breadboards with the included header
- Driving powered speakers or amplifier inputs from digital audio sources
Also Consider
- PCM5102 I2S DAC (112dB SNR) – Same audio quality, hardware mode only, lower cost
- PCM5100 I2S DAC (100dB SNR) – Good quality, hardware mode only, most affordable
Package Contents
- 1× PCM5122 I2S Stereo DAC Breakout
- 1× Header strip for breadboard use
Jargon buster
Plain-language definitions for the technical terms used above.
- breakout
- A breakout is a small circuit board that makes a tiny or hard-to-solder component easier to connect to with standard pins. It matters because this OLED module can be wired into a microcontroller project without needing to solder directly to the display’s fine contacts.
- DAC
- A digital-to-analogue converter turns numbers from the microcontroller into a real analogue voltage. It matters if you want to generate simple waveforms, audio-style signals, or variable control voltages rather than just on/off outputs.
- DIN
- DIN means data in, the pin where this display receives data from the controller. Connecting DIN to the correct SPI data output pin is needed for the screen to receive pixel and command information.
- ESP32
- ESP32 is a family of microcontroller modules with built-in wireless features such as Bluetooth and WiFi. Knowing this product uses an ESP32-based module helps explain how it provides wireless serial communication and firmware update features.
- I2C
- I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.
- I2S
- I2S is a digital audio interface used to send sound data between chips, such as from a microcontroller to an audio amplifier or DAC. It matters if your project needs cleaner digital audio output than a basic buzzer or PWM signal can provide.
- RP2350
- A microcontroller chip from Raspberry Pi used as the main processor on some development boards. Knowing the board is built around an RP2350 helps you check software support, pin capabilities and whether it suits MicroPython projects.
- SPI
- A fast serial communication bus often used for displays, memory cards, and sensors. It matters because SPI devices need specific pins for clock and data, plus a separate chip-select line for each device.
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