1 Features

1• On-Chip USB Interface:

– No Dedicated Device Driver Needed

– Full-Speed Transceivers

– Fully Compliant With USB 2.0 Specification

– USB 1.1 Descriptors With USB Audio Class

Support

– Certified by USB-IF

– Partially Programmable Descriptors

– Adaptive Isochronous Transfer for Playback

– Bus-Powered or Self-Powered Operation

• Sampling Rates: 32 kHz, 44.1 kHz, and 48 kHz

• On-Chip Clock Generator With Single 12-MHz

Clock Source

• Single Power Supply:

– Bus-Powered: 5 V, Typical (VBUS)

– Self-Powered: 3.3 V, Typical

• 16-Bit Delta-Sigma Stereo DAC

– Analog Performance at 5 V (Bus-Powered),

3.3 V (Self-Powered):

– THD + N: 0.006% R L > 10 kΩ, Self-

Powered

– THD + N: 0.025% R L = 32 Ω

– SNR = 98 dB

– Dynamic Range: 98 dB

– P O = 12 mW, RL = 32 Ω

– Oversampling Digital Filter

– Passband Ripple = ±0.04 dB

– Stop-Band Attenuation = –50 dB

– Single-Ended Voltage Output

– Analog LPF Included

• Multiple Functions:

– Up to Eight Human Interface Device (HID)

Interfaces (Model and Setting Dependent)

– Suspend Flag

– S/PDIF Out With SCMS

– External ROM Interface (PCM2704C/6C)

– Serial Programming Interface (PCM2705C/7C)

– I2S Interface (Selectable on PCM2706C/7C)

2 Applications

• USB Headphones

• USB Audio Speaker

• USB CRT/LCD Monitor

• USB Audio Interface Box

• USB-Featured Consumer Audio Product

3 Description

The PCM270xC are TI's single-chip USB stereo audio digital-to-analog converters (DACs) with USB

2.0 compliant full-speed protocol controller and

S/PDIF. The USB-protocol controller works with no

software code, but USB descriptors can be modified

in some areas (for example, vendor ID/product ID)

through the use of an external ROM (PCM2704C and

PCM2706C) or serial peripheral interface (SPI)

(PCM2705C and PCM2707C). The PCM270xC also

employ SpAct™ architecture, TI's unique system that

recovers the audio clock from USB packet data. On-

chip analog phase-locked loops (PLLs) with SpAct

enable playback with low clock jitter.