Datasheet

D+/D–
SEL1 (Pin 9)
2.5 V (Typ)
0 V
Internal Reset
Ready for Setup
Attach
(Connect to USB Bus)
SOF
Ready for Playback
Bus Reset
Set Configuration
SOF SOF
BPZ
Bus Idle
3.3 V (Typ)
SSPND
700 sm
Device Setup
1 ms
5 V = V
(Typ)
BUS
V (Pin 27)
DD
V L
V R
OUT
OUT
First Audio Data
Second Audio Data
PCM2903C
www.ti.com SBFS038 –JUNE 2012
INTERFACE SEQUENCE
Power On, Attach, and Playback Sequence
The PCM2903C is ready for setup when the reset sequence has finished and the USB bus is attached. In order
to perform certain reset sequences defined in the USB specification, V
DD
, V
CCC
, V
CCP1
, V
CCP2
, and V
CCX
must rise
up within 10 ms / 3.3 V. After connection has been established by setup, the PCM2903C is ready to accept USB
audio data. While waiting, the audio data (idle state) and analog output are set to bipolar zero (BPZ).
When receiving the audio data, the PCM2903C stores the first audio packet, which contained 1-ms audio data,
into the internal storage buffer. The PCM2903C starts playing the audio data when detecting the next start of
frame (SOF) packet, as illustrated in Figure 35 and Figure 36.
Figure 35. Attach After Power On
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Product Folder Link(s): PCM2903C