UDA1334BTS 데이터 시트보기 (PDF) - Philips Electronics
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UDA1334BTS Datasheet PDF : 20 Pages
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Philips Semiconductors
Low power audio DAC
Preliminary specification
UDA1334BTS
8 FUNCTIONAL DESCRIPTION
8.1 System clock
The UDA1334BTS operates in slave mode only; this
means that in all applications the system must provide the
system clock and the digital audio interface signals
(BCK and WS).
The system clock must be locked in frequency to the digital
interface signals.
The UDA1334BTS automatically detects the ratio between
the SYSCLK and WS frequencies.
The BCK clock can be up to 64fs, or in other words the
BCK frequency is 64 times the Word Select (WS)
frequency or less: fBCK ≤ 64 × fWS.
Remarks:
1. The WS edge MUST fall on the negative edge of the
BCK at all times for proper operation of the digital I/O
data interface
2. For LSB-justified formats it is important to have a WS
signal with a duty factor of 50%.
The modes which are supported are given in Table 1.
Table 1 Supported sampling ranges
CLOCK MODE
768fs
512fs
384fs
256fs
192fs
128fs
SAMPLING RANGE
8 to 55 kHz
8 to 100 kHz
8 to 100 kHz
8 to 100 kHz
8 to 100 kHz(1)(2)
8 to 100 kHz(2)
Notes
1. This mode can only be supported for power supply
voltages down to 2.4 V. For lower voltages, in
192fs mode the sampling frequency should be limited
to 55 kHz.
2. Not supported in the low sampling frequency mode.
Table 2 Example using a 12.228 MHz system clock
CLOCK MODE
128fs
192fs
256fs
384fs
512fs
768fs
SAMPLING FREQUENCY
96 kHz
64 kHz(1)
48 kHz
32 kHz
24 kHz
16 kHz
Note
1. This mode can only be supported for power supply
voltages down to 2.4 V. For lower voltages, in 192fs
mode the sampling frequency should be limited to
55 kHz.
8.2 Interpolation filter
The interpolation digital filter interpolates from 1fs to 64fs
by cascading FIR filters (see Table 3).
Table 3 Interpolation filter characteristics
ITEM
Pass-band ripple
Stop band
Dynamic range
CONDITION
0 to 0.45fs
>0.55fs
0 to 0.45fs
VALUE (dB)
±0.02
−50
>114
8.3 Noise shaper
The 5th-order noise shaper operates at 64fs. It shifts
in-band quantization noise to frequencies well above the
audio band. This noise shaping technique enables high
signal-to-noise ratios to be achieved. The noise shaper
output is converted into an analog signal using a
Filter Stream DAC (FSDAC).
An example is given in Table 2 for a 12.228 MHz system
clock input.
2000 Feb 07
7
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