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.