Chip-level audio testing

validation and characterization performed directly on the chip package of an audio integrated circuit (IC). This testing is crucial for ensuring the IC meets its design specifications and performs reliably in real-world audio applications. It is significantly more granular and detailed than system-level testing.

Breakdown of what chip-level audio testing entails

1. Test Objectives:

Verify functionality:

• Ensure that all audio blocks (ADC, DAC, amplifiers, filters, DSP cores, etc.) operate as intended according to the design specifications.

Performance parameters (measure the chip’s audio performance):

• Signal-to-Noise Ratio (SNR) Meaning: the audio I want to hear (the signal) compared to how much unwanted background sound (the noise) is present.
• Total Harmonic Distortion + Noise (THD+N)
• Dynamic Range (DR)
• Frequency Response
• Intermodulation Distortion (IMD)
• Channel separation (Crosstalk)
• Gain accuracy and linearity
• Input and output impedance
• Power consumption
• Stability (avoiding oscillations)

Identify defects:

• manufacturing defects,
• design flaws, or
• process variations that could affect audio performance.

Ensure reliability:

• Verify that the chip can withstand stress conditions (temperature, voltage, humidity) and maintain its performance over its intended lifespan.

2. Test Environment:

Automated Test Equipment (ATE):

• Specialized test equipment designed for automated chip testing.
• provide precise voltage sources, current meters, waveform generators, analyzers, and digital I/O.
• programmable to run a suite of tests automatically.

Probe Card:

• A custom-designed printed circuit board (PCB) with fine needles (probes) that make temporary electrical contact with the IC’s pads (bond pads) directly on the silicon wafer or packaged chip.

Load Board:

• A PCB that provides the circuitry for connecting the ATE to the DUT (may include filters, amplifiers, level shifters, and other components to optimize the test setup).

Shielding:

• Critical to minimize noise and interference in sensitive audio measurements.

Temperature Control:

• ATE systems often have temperature chambers to control the temperature of the DUT.