Experience Audio Perfection: The New Cirrus Logic DAC

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Pro-Audio 2:10

Inside Cirrus Logic’s Highest‑Performance DAC

Cirrus Logic’s breakthrough DAC architecture delivers transparent, high‑performance audio with exceptional dynamic range, clean output, and optimized FIR filtering across professional and consumer applications.

At Cirrus Logic, our mission is to deliver audio that’s as true to the original as possible. Our latest continuous-time, current-output Digital-to-Analog Converter (DAC) family is engineered for both professional and consumer audio, setting new benchmarks for transparency.


David Singleton provided an overview of how we achieve this in his AES paper, highlights of which are covered in this article.

What Makes Our DAC Special?

Continuous-Time, Current-Output Architecture

Our DAC supports input sample rates up to 768kHz and achieves an impressive 128dB dynamic range (8Vrms output), with -115dB THD+N and -123dB THD. This architecture uses digital sigma-delta and PWM modulation to generate a digital data stream. This is then reconstructed using an advanced Analog Finite Impulse Response (AFIR) filter built from high-precision current-DAC elements.

  • Current-to-voltage conversion is performed off-chip, allowing output voltage levels to be optimized for any system by simply adjusting the external resistor.

  • Fully differential design ensures constant current draw, minimizing supply sensitivity and crosstalk.

All-FIR Interpolation Path

The DAC features 26 unique FIR (Finite Impulse Response) interpolation filters, each with coefficients tailored to the selected sample rate (from 48kHz to 768kHz). These filters use 61-bit accumulator precision for a true 32-bit output signal path, and are inherently free from limit-cycle tonal behaviour thanks to an all-FIR implementation.

  • Filter profiles: Choose between linear or minimum phase response, with fast, slow, or balanced roll-off options.

  • Balanced roll-off filters (for rates above 88.2kHz) offer an optimal compromise between transition band width, filter order, and impulse response, resulting in a flat passband and high stopband attenuation with very minimal impulse response ringing.

  • Dithered arithmetic ensures quantization noise is white, preserving clarity even at low levels.

Hybrid Sigma-Delta and PWM Modulation

Our unique approach combines the noise-shaping capability of sigma-delta modulation with the purity of pulse-width modulation. The audio input is interpolated up to 6.144MHz, then reduced to 5 bits using a high-order CRFB sigma-delta modulator, before being modulated to 2 PWM bits.

  • PWM encoding runs at 49MHz, eight times faster than the SDM, driving two parallel AFIRs for differential output.

  • Co-designed SDM and PWM blocks ensure no observable error from PWM encoding, maintaining signal integrity.

AFIR Filter Technology

The AFIR filter is constructed from 256 current-output elements arranged in a shift register, forming a low-pass filter response with notches at PWM carrier image frequencies. This design:

  • Minimizes jitter sensitivity and out-of-band noise, relaxing clock requirements, and simplifying system integration.

  • Differential AFIRs cancel common-mode errors, including PWM carrier and intermodulation components.

  • AFIR length and weightings are optimized for an excellent balance of area, power, and performance.

Real-World Results

Our DAC’s performance speaks for itself:

  • Dynamic Range: 128dB (A-weighted)

  • THD+N Ratio: -115dB

  • Channel Separation: 110dB

  • Power Consumption: Just 67mW per channel

These numbers on their own do not guarantee a great sonic experience. By combining this raw performance with what we believe is an inherently high-fidelity architecture, however, with the right design trade-offs, this translates into a listening experience that’s both powerful and refined, with a fantastic soundstage, precise timing, and a relaxed, musical feel.

Designed for Audio Enthusiasts, by Audio Experts

This breakthrough is the result of over 20 years of dedicated development by our talented engineering team. Every aspect of the DAC—from filter design to output architecture—has been carefully crafted and auditioned to ensure world-class performance.

Discover the Future of Audio

Ready to experience audio perfection? The new Cirrus Logic DAC, CS4302P, is available now for integration into your next product. Whether you’re designing for the studio, stage, or living room, our technology will help you deliver sound that inspires. For more information visit our pro audio and DAC product pages.

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