GENERAL DESCRIPTION

The SAA7715 is a cost effective and powerful high performance 24-bit programmable DSP for a variety of digital audio applications. This DSP device integrates a 24-bit DSP core with programmable memories (program RAM/ROM, data and coefficient RAM), 4 digital serial inputs, 4 digital serial outputs, 2 separate SPDIF receivers, a stereo FSDAC, a standard Philips I2C-bus interface, a phase-locked loop for the DSP clock generation and a second phase-locked loop for system clock generation (internal and external DAC clocks).

FEATURES

Hardware

• 24-bit Philips 70 MIPS DSP core (24-bit data path and 12/24-bit coefficient path)

• 1.5 kbyte of downloadable DSP program memory (PRAM)

• 2 kbyte of DSP program memory (PROM)

• 2.5 kbyte of re-programmable DSP data memory (XRAM)

• 512 byte of re-programmable DSP coefficient memory (YRAM)

• Four stereo digital serial inputs (8 channels) with common BCK and WS. To these inputs the I2S-bus format or LSB-justified formats can be applied

• One stereo bitstream DAC (2 channels) with 64 fold oversampling and noise shaping

• Selectable clock output (pin SYSCLK) for external slave devices (512fs to 128fs)

• Four stereo digital serial outputs (8 channels) with selectable I2S-bus or LSB-justified format

• Two SPDIF inputs combined with digital serial input

• On-board WS_PLL generates clock for on-board DAC and output pin SYSCLK

• I2C-bus controlled (including fast mode)

• Programmable Phase-Locked Loop (PLL) derives the clock for the DSP from the CLK_IN input

• −40 to +85 °C operating temperature range

• supply voltage only 3.3 V

• All digital inputs are tolerant for 5 V input levels

• Power-down mode for low current consumption in standby mode

• Optimized pinning for applications with other Philips DACs (such as UDA1334, UDA1355 and UDA1328).

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APPLICATIONS

• As co-processor for a car radio DSP in a car radio application for additional acoustic enhancements (sound steering/sound elevation/signal processing)

• Multichannel audio: in DVD and Home theatre applications as post-processing device like signal virtualisation (virtual 3D surround) and acoustic enhancement, tone control, volume control and equalizers

• Multichannel decoding: Dolby Pro Logic and virtual 3D surround

• PC/USB audio applications: stereo widening (Incredible surround), sound steering, sound positioning and speaker equalization.