AK4438VN

ADCs/DACs - Special Purpose Overview

The AK4438VN is an 8-channel, 32-bit audio digital-to-analog converter (DAC) from Asahi Kasei Microdevices. It supports PCM input sampling rates up to 768 kHz and utilizes OSR-Doubler technology for low out-of-band noise and power efficiency. The device features five selectable digital filters with short group delay options. Key electrical specifications include a dynamic range of 108 dB, THD+N of 91 dB at 48 kHz, and channel-independent digital volume control ranging from 0 dB to −127 dB in 0.5 dB steps. It operates on AVDD (3.0 V–3.6 V) and TVDD (1.7 V–3.6 V) supplies within an operating temperature range of −40 °C to 105 °C.

ADCs/DACs - Special Purpose Feature Summary

• 8-channel 32-bit DAC architecture supporting sampling frequencies from 8 kHz to 768 kHz across Normal, Double, Quad, Oct, and Hex Speed modes.
• Integrated digital volume control with 0.5 dB step resolution (0 dB to −127 dB), soft mute, de-emphasis filter, and zero detection.
• Five types of digital filters including Sharp Roll-Off, Slow Roll-Off, and Short Delay variants for flexible system design.
• Supports MSB justified, LSB justified, I2S, and TDM audio interfaces via 3-wire serial or I2C bus control.

ADCs/DACs - Special Purpose Applications

• AV Receivers
• CD/SACD Players
• Network Audio Systems
• USB DACs and USB Headphones
• Car Audio Systems

ADCs/DACs - Special Purpose Procurement Notes

Verify the package type is 32-pin QFN with 0.5 mm pitch. Confirm that the exposed bottom pad is connected to analog ground as required by the datasheet. Ensure external capacitors meet the specified tolerance (e.g., 2.2 µF ± 50% for LDOO and VCOM pins). Check that supply voltages remain within the recommended operating conditions to avoid permanent damage.

ADCs/DACs - Special Purpose Selection Notes

Select this component for high-resolution audio applications requiring multi-channel output without external multiplexing. Consider the specific digital filter characteristics, such as group delay and passband ripple, when designing for latency-sensitive systems. Ensure the master clock frequency aligns with the selected sampling speed mode (e.g., 256fs for Normal Speed). Verify interface compatibility with the host controller for I2C or 3-wire serial control.

ADCs/DACs - Special Purpose Part Context

The AK4438VN belongs to the AK4x series of audio D/A converters from Asahi Kasei Microdevices. This series utilizes original digital-analog mixing technology designed for high-quality audio systems. The VN suffix indicates the specific 32-pin QFN package variant suitable for surface-mount assembly in compact consumer electronics and automotive environments.

ADCs/DACs - Special Purpose Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Designers should consult the manufacturer's official cross-reference guides or contact technical support for verified alternatives.

ADCs/DACs - Special Purpose FAQ

What is the maximum supported sampling rate for the AK4438?

The AK4438 supports PCM input sampling rates up to 768 kHz in Hex Speed mode.

How is the common voltage output pin (VCOM) handled?

The VCOM pin outputs a common voltage equal to AVDD × 1/2. A large external capacitor of 2.2 µF ± 50% must be connected to this pin to reduce power-supply noise.

What control interfaces are supported?

The device supports a 3-wire Serial interface and an I2C bus interface (Fast mode: 400 kHz) for register configuration and control.

What happens if the master clock stops during operation?

If the clock stops, click noise may occur upon restarting. The datasheet recommends muting the analog output externally if this noise affects system performance.