Keep (Analog Ground) and DGND (Digital Ground) isolated under the chip.
| Model | Channels | DAC SNR | Package | Key Differences | |-------|----------|---------|---------|-----------------| | | 4‑channel | 98 dB | QFN‑48 | Very similar; shares driver quirks. ALC269 has different COEF tables. | | ALC271X | 4‑channel | 98 dB | QFN‑48 | 2 W Class‑D amp; 4‑pin headset detection quirks in Linux. | | ALC272 | 4‑channel | 98 dB | QFN‑48 | Slightly lower power consumption; different pinout. | | ALC892 | 8‑channel | 108 dB | LQFP‑48 | Premium variant; higher SNR; used in desktop motherboards. | | ALC662 | 5.1‑channel | 93 dB | QFN‑48 | Older, lower‑spec; AC'97 / HD Audio dual interface. | alc271x datasheet
The IC is typically packaged in a space-saving layout, measuring 6mm x 6mm. Variations include the ALC271X-VB3-GR and ALC271X-VB6-CG , which feature specialized silicon steppings but maintain fundamentally compatible core pin definitions. Function Type Pin Description HDA_BIT_CLK Digital Input 24MHz bit clock input from host controller HDA_SDATA_OUT Digital Input Serial data input stream from controller HDA_SDATA_IN Digital Output Serial data output stream to controller HDA_SYNC Digital Input Frame sync signal mapping audio samples HDA_RST# Digital Input Active low hardware reset signal LINE1-L / LINE1-R Analog Input Stereo line-level input channels MIC1-L / MIC1-R Analog Input Microphone inputs with configurable pre-amps HP-OUT-L / R Analog Output High-current headphone driver outputs AVDD / DVDD Power Supply Analog (3.3V to 5V) and Digital (1.5V to 3.3V) rails Technical Circuit Design and Implementation Keep (Analog Ground) and DGND (Digital Ground) isolated
The current stable approach includes defined in hd‑audio‑models.rst : | | ALC271X | 4‑channel | 98 dB