NXP Semiconductors DSPB56721CAF

Overview

DSPB56721CAF from Freescale Semiconductor is a dual-core 24-bit audio DSP engineered for high-fidelity, multi-stream audio processing in automotive and consumer systems. It delivers 200 MIPS per core at 200 MHz internal clock, integrates two DSP56300 cores, on-chip ASRC, S/PDIF transceivers, ESAI interfaces, and Inter-Core Communication (ICC). It targets HD-Audio decoding (Dolby TrueHD, DTS-HD) in car audio amplifiers and A/V receivers.

For engineers reviewing the DSPB56721CAF datasheet, DSPB56721CAF pinout, DSPB56721CAF application, or DSPB56721CAF equivalent, key selection criteria include its 80-pin LQFP package, absence of external memory controller (vs. DSP56720), 1.0 V core / 3.3 V I/O supply scheme, and support for synchronous audio routing via ESAI and S/PDIF.

Technical Context

The DSPB56721CAF implements two independent DSP56300 24-bit cores sharing 64 KB of on-chip RAM across eight 8-KB blocks and 8 KB of shared memory. Its architecture includes dedicated audio peripherals: four ESAI modules (ESAI, ESAI_1, ESAI_2, ESAI_3), dual S/PDIF transceivers (SPDIFIN1/OUT1, SPDIFIN2–4/OUT2), and an Asynchronous Sample Rate Converter (ASRC) for sample domain bridging between independent clock domains.

It lacks the External Memory Controller (EMC) present in the DSP56720, confirming its role as a self-contained, memory-limited audio processor optimized for deterministic latency and compact PCB layout. Power sequencing mandates IO_VDD ramp before CORE_VDD, with Core_VDD ramp time <10 ms to ensure reliable power-on reset operation.

Key Specifications

Pinout & Package

Package: 80-pin plastic LQFP, 14 mm × 14 mm, 0.65 mm pitch, exposed pad not specified.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multi-core audio DSP applications.

Compared with ADSP-21489KSWZ-4 and DSP56720F144, the DSPB56721CAF offers superior integration of audio-specific peripherals (ASRC, dual S/PDIF, four ESAIs) in a compact 80-pin package, trading raw memory scalability for lower system-level BOM count and deterministic audio latency.

Availability

DSPB56721CAF is available at Aetrix Electronics and suitable for car audio amplifiers, A/V receivers, professional sound mixers, and Blu-ray player audio engines requiring stable component supply and long-term industrial availability.

Supply support for DSPB56721CAF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Freescale Semiconductor (now part of NXP Semiconductors) is a fabless semiconductor company specializing in embedded processing, connectivity, and analog solutions for automotive, industrial, and consumer markets.

The DSP5672x Symphony family was designed specifically for high-performance, low-latency audio signal processing in resource-constrained embedded systems - emphasizing integrated audio peripherals, deterministic timing, and automotive-grade reliability.

FAQ

What is the core voltage requirement for stable operation of the DSPB56721CAF?

The DSPB56721CAF requires CORE_VDD between 0.9 V and 1.1 V (typical 1.0 V) for commercial operation, and 0.95 V to 1.05 V for automotive grade. The power-on ramp time must be under 10 ms to ensure correct POR behavior. Exceeding these limits risks functional failure or reduced reliability. The DSPB56721CAF datasheet specifies that IO_VDD must rise before CORE_VDD to prevent latch-up.

Does the DSPB56721CAF support external SDRAM expansion?

No, the DSPB56721CAF does not include an External Memory Controller (EMC). Unlike the DSP56720, it relies solely on its 64 KB of on-chip RAM and 8 KB of shared memory. This design choice reduces pin count and PCB complexity but limits working memory to on-die resources. For applications requiring more than 64 KB of fast-access memory, the DSP56720 or alternative processors with EMC must be considered. The DSPB56721CAF datasheet explicitly states this distinction in Section 1.

How many S/PDIF interfaces does the DSPB56721CAF provide?

The DSPB56721CAF provides two fully independent S/PDIF transceivers: SPDIFIN1/SPDIFOUT1 (primary) and SPDIFIN2–4/SPDIFOUT2 (secondary with four inputs, one output). This enables simultaneous reception and transmission of compressed digital audio streams - for example, receiving Dolby Digital from a set-top box while outputting processed PCM to an external DAC. The DSPB56721CAF pinout confirms dedicated pins for both channels in its 80-pin LQFP package.

What clock frequencies does the DSPB56721CAF support via its on-chip PLL?

The DSPB56721CAF PLL accepts an external crystal or square-wave input (EXTAL) from 2.5 MHz to 100 MHz. With PLL enabled, it generates an internal 200–400 MHz VCO frequency and outputs a 25–200 MHz system clock (Fout). The typical configuration uses a 24.576 MHz crystal to derive exact 44.1 kHz and 48 kHz audio sample rates. The DSPB56721CAF Reference Manual details register settings for NR, NF, and NO dividers to achieve target frequencies.

Is the DSPB56721CAF pin-compatible with other devices in the DSP5672x family?

No, the DSPB56721CAF is not pin-compatible with the 144-pin variants (DSP56720 or DSP56721 144-pin). It uses an 80-pin LQFP package with distinct pin assignments - including consolidated ESAI/S/PDIF functions and omission of EMC-related signals. Pin compatibility exists only within same-package variants (e.g., DSPB56721CAF vs. other 80-pin DSP56721 derivatives). The DSPB56721CAF datasheet's Table 1 and Figures 4–5 confirm this package-specific mapping.