The AD1938 is a high performance, single-chip codec that provides four analog-to-digital converters (ADCs) with input and eight digital-to-analog converters (DACs) with single-ended output using the Analog Devices, Inc., patented multibit sigma-delta (Σ-Δ) architecture. An SPI port is included, allowing a microcontroller to adjust volume and many other parameters.The AD1938 operates from 3.3 V digital and analog supplies. The AD1938 is available in a 48-lead (single-ended output) LQFP package. Other members of this family include a differential DAC output and I2C®control port version.The AD1938 is designed for low EMI. This consideration is apparent in both the system and circuit design architectures. By using the on-board PLL to derive the master clock from the LR clock or from an external crystal, the AD1938 eliminates the need for a separate high frequency master clock and can also be used with a suppressed bit clock. The DACs and ADCs are designed using the latest Analog Devices continuous time architectures to further minimize EMI. By using 3.3 V supplies, power consumption is minimized, further reducing emissions.APPLICATIONSAutomotive audio systemsHome Theater SystemsSet-top boxesDigital audio effects processors

The AD1954 is a complete 26-bit single-chip 3-channel digital audio playback system with built-in DSP functionality for speaker equalization, dual-band compression/limiting, delay compensation, and image enhancement. These algorithms can be used to compensate for real-world limitations of speakers, amplifiers, and listening environments, resulting in a dramatic improvement of perceived audio quality.The signal processing used in the AD1954 is comparable to that found in high-end studio equipment. Most of the processing is done in full 48-bit double-precision mode, resulting in very good low-level signal performance and the absence of limit cycles or idle tones. The compressor/limiter uses a sophisticated two-band algorithm often found in high-end broadcast compressors.An extensive SPI port allows click-free parameter updates, along with read-back capability from any point in the algorithm flow.The AD1954 includes ADI’s patented multibit sigma-delta DAC architecture. This architecture provides 112 dB SNR and dynamic range and THD+N of –100 dB. These specifications allow the AD1954 to be used in applications ranging from low-end boom boxes to high-end professional mixing/editing systems.The AD1954 also has a digital output that allows it to be used purely as a DSP. This digital output can also be used to drive an external DAC to extend the number of channels beyond the three that are provided on the chip.This chip can be used with either its default signal processing program or with a custom user-designed program. Graphical programming tools are available from ADI for custom programming.APPLICATIONS2.0/2.1 Channel Audio Systems (Two Main Channels plus Subwoofer)Multimedia AudioAutomotive Sound SystemsMinicomponent StereoHome Theater Systems (AC-3 Postprocessor)Musical InstrumentsIn-Seat Sound Systems (Aircraft, Motor Coaches)

The AD1955 is a complete, high performance, single chip stereo digital audio playback system comprised of a multi-bit sigma-delta modulator, digital interpolation filters and a continuous-time differential current output DAC section. Unique to this audio DAC is the separate SACD (super audio CD) bit-stream and external digital filter interface, which allows users maximum system flexibility. The AD1955 supports 24-bits, 192 kHz sample rate and is designed for use in high-end SACD players, DVD-audio, home theater, automotive audio, digital mixing consoles, digital audio effect processors and sampling musical keyboards.APPLICATIONSHigh-End DVD-Audio, SACD, CD, Home Theatre SystemsAutomotive Audio Systems, Sampling Musical Keyboards, DigitalMixing Consoles, Digital Audio Effects Processors