
1998 Oct 06
3
Philips Semiconductors
Preliminary specification
Universal Serial Bus (USB)
Digital-to-Analog Converter (DAC)
UDA1321
The control information becomes accessible at the
microcontroller. The audio information becomes available
at the digital I/O output or is fed directly to the ADAC.
The microcontroller handles the high-level USB protocols,
translates the incoming control requests and manages the
user interface via General Purpose (GP) pins and an
I
2
C-bus.
The ADAC enables the wide and continuous range of input
sampling frequencies. By means of a Sample Frequency
Generator (SFG), the ADAC is able to reconstruct the
average sample frequency from the incoming audio
samples. The ADAC also performs the sound processing.
The ADAC consists of FIFO registers, a unique audio
feature processing DSP, the SFG, digital up-sampling
filters, a variable hold register, a Noise Shaper (NS) and a
Filter Stream DAC (FSDAC) with integrated filter and line
output drivers. The audio information is applied to the
ADAC via the USB processor or via the digital I/O input.
An external DSP can be used for adding extra sound
processing features via the digital I/O-bus.
The UDA1321 supports the standard I
2
S-bus data input
format and the LSB-justified serial data input format with
word lengths of 16, 18 and 20 bits.
The wide dynamic range of the bitstream conversion
technique used in the UDA1321 guarantees a high audio
sound quality.
QUICK REFERENCE DATA
Notes
1.
V
DD
is the supply voltage on pins V
DDA
, V
DDE
, V
DDI
and V
DDX
. V
SS
is the ground on pins V
SSA
, V
SSE
, V
SSI
and V
SSX
.
All V
DD
and V
SS
pins must be connected to the same supply or ground respectively.
The audio information from the USB interface is fed directly to the ADAC.
The power-save mode (power management) is not supported in the UDA1321/N101;
see Chapter “USB-DAC UDA1321/N101 (Firmware sw 2.1.1.7)”.
2.
3.
SYMBOL
PARAMETER
CONDITIONS
MIN.
TYP.
MAX.
UNIT
Supplies
V
DD
I
DD(tot)
I
DD(ps)
supply voltage
total supply current
supply current in power-save
mode
note 1
3.0
3.3
50
18
3.6
V
mA
mA
note 3
Dynamic performance DAC
total harmonic
distortion-plus-noise to signal
ratio
f
s
= 44.1 kHz; R
L
= 5 k
at input signal of 1 kHz (0 dB)
90
(2)
0.0032 0.01
30
(2)
3.2
95
80
dB
%
dB
%
dBA
at input signal of 1 kHz (
60 dB)
20
10
90
S/N
bz
signal-to-noise ratio at bipolar
zero
full-scale output voltage
(RMS value)
A-weighted at code 0000H
V
o(FS)(rms)
V
DD
= 3.3 V
0.66
V
General characteristics
f
i(sample)
T
amb
audio sample input frequency
operating ambient temperature
5
0
25
55
70
kHz
°
C
THD
N
+
S