Stereo/multi-channel codecs, high-performance ADC/DAC, mic front-ends, headphone/line amps, speaker amps, DSP/algorithms (ANC/AEC/NS/beamforming), interfaces & clocking, power & supplies, key specs, design hooks, and application recipes.
Codecs & Converters
Stereo / Multi-Channel Audio Codec
Integrated ADC+DAC with MIC bias and HP/line drivers; I²S/TDM/PCM for conferencing, Hi-Fi, IVI.
High-Performance Audio ADC (ΣΔ)
24–32-bit up to 192–768 kHz; SNR/DR/THD+N optimized for recording and metrology.
High-Performance Audio DAC (ΣΔ/R-2R)
32-bit with jitter rejection and selectable filters (sharp/slow/apodizing) for hi-fi playback.
Microphone Front-End
Analog MIC Preamplifier
Low-noise, selectable gain, high AOP for instruments, stage and in-vehicle arrays.
PDM Microphone Interface
PDM↔I²S/PCM de-serialization with clocking for arrays and beamforming.
MIC Bias & Protection
Programmable bias with over-voltage/ESD protection for reliability.
Headphone & Line Amps
Headphone Amplifier (HPA)
Direct-drive or capless/BTL with low noise floor/Zo and pop-noise control.
Line Driver / Receiver (Balanced/SE)
2 Vrms+ balanced links for long cables and high CM rejection in pro/broadcast.
Speaker Power Amplifiers
Class-D Speaker Amp (BTL/SE/1SPW/BD)
High efficiency with EMI mitigation (spread-spectrum/diff-PWM) and load-tolerance.
Multi-Channel Class-D
2.0/2.1/5.1/7.1 with built-in mixer/limiter for bars and IVI.
Speaker Protection / Diagnostics
Distortion monitoring, thermal/DC offset detection and open/short alarms.
Processing & Algorithms
Audio DSP / SoC
On-chip EQ/DRC/AGC, crossovers and spatialization with GUI tuning & OTA.
Active Noise Cancellation (ANC)
Feedforward/feedback/hybrid with low-latency paths; leakage and wind handling.
AEC / Noise Suppression
Far-end reference, adaptive filtering and double-talk detection.
Beamforming / DOA
PDM-array calibration with delay-and-sum or adaptive methods.
Interfaces & Clocking
Digital Audio Buses (I²S/LJ/RJ/TDM/PCM/PDM)
Master/slave modes; bit-depth/sample-rate and jitter sensitivity.
Control Interfaces (I²C/SPI/SDIO)
Configure volume/gain and routing matrices.
Audio PLL / Clocking
24.576/22.5792 MHz families with ASRC for unstable USB/network clocks.
Power & Supply
Codec/Headphone Rails
Partition AVDD/DVDD/HPVDD with close-in decoupling and PSRR awareness.
Class-D PVDD Supply
High ripple/pulsating currents; near-input/output caps and single-point grounding.
Low-Noise LDO & Reference
Prefer LDOs in analog domains; sync switchers outside audio band.
Key Specs & Selection
ADC/DAC Metrics
SNR/DR, THD+N, IMD, linearity and phase/group delay.
Headphone Metrics
Max V/I, output Z, noise (µV/µVrms), pop/click and crosstalk.
Amplifier Metrics
Rated W@Ω@THD+N, efficiency, PSRR, fsw/EMI and protections.
Clocking Metrics
Jitter (psrms), ASRC range and 44.1/48k families with multiples.
System Metrics
Latency budgets (AEC/ANC), multi-channel sync (TDM/WS delay) and standby power.
Design Hooks & Pitfalls
Ground Partitioning
Strict analog vs. Class-D power return separation with single-point tie.
I/O & EMI Filtering
Class-D LC/EMI sized to speaker Ω; watch cable radiation.
Pop/Click Control
Power-up/down sequence, soft-start/mute pins and bias ramps.
Clocks & Sample Rates
ASRC for async USB/network; unify master/slave and clock tree.
Mic-Array Consistency
Match sensitivity/phase; model wind/plosive and echo paths.
Thermals
Heatsink/copper via arrays; leave thermal margin in BOM.
EMI & PSRR
Speaker cables radiate; tune PWM freq/spread, twist/shield and guard analog rails.
User Safety
Limiter for hearing safety, jack detect and DC-bleed safeguards.
Application-Focused
Conferencing & Soundbars
Multi-codec + mic arrays + AEC/NS + multi-channel Class-D + HDMI/eARC.
Wearables / Headphones
Ultra-low-power codec + direct-drive HPA + ANC DSP with battery/charger synergy.
Automotive IVI
Multi-channel codec + automotive Class-D with start/stop pop control and diagnostics.
Pro Recording / Measurement
High-SNR ADC/DAC, clean clocks, balanced I/O and low-latency USB Audio.
Quick Cheats
SPL vs. Power
SPL ≈ 112 dB + 10·log10(Pout[W]) + sensitivity correction (@1 m/1 W approx.).
Headphone Output-Z Rule
Output-Z ≪ headphone Z (often <1/8) to keep flat frequency response.
Amp Thermal Headroom
Ploss ≈ Pin − Pout; ΔT ≈ Ploss × RθJA → check copper & airflow.
