uda1338h-n1 NXP Semiconductors, uda1338h-n1 Datasheet - Page 8

• Manufacturer Part Number: uda1338h-n1
• Description: Multichannel Audio Coder-decoder
• Manufacturer: NXP Semiconductors

Philips Semiconductors
9397 750 14389
Product data sheet
8.2 Audio analog-to-digital converter (audio ADC)
8.3 Voice analog-to-digital converter (voice ADC)
8.4 Decimation filter of audio ADC
Table 6:
The audio analog-to-digital front-end of the UDA1338H consists of 4-channel
single-ended Adds with programmable gain stage (from 0 dB to 24 dB with 3 dB steps),
controlled via the microcontroller interface. Using the PGA feature, it is possible to accept
an input signal of 900 mV (RMS) or 1.8 V (RMS) if an external resistor of 10 k is used in
series. The schematic of audio ADC front-end is shown in
The voice analog-to-digital front-end of the UDA1338H consists of a single-channel
single-ended ADC with a fixed gain (26 dB) Low Noise Amplifier (LNA). Together with the
digital variable gain amplification stage, the voice ADC provides optimal processing and
reproduction of the microphone signal. The supported sampling frequency range is from
7 kHz to 50 kHz. Power-down of the LNA and the ADC can be controlled separately.
The decimation from 64f
characteristics with a decimation factor of 8. The second stage consists of three half-band
filters, each decimating by a factor of 2. The filter characteristics are shown in
Table 7:
Mode
WSV-in
WSV-out
Item
Pass-band ripple
Pass-band droop
Stop band
Dynamic range
Fig 3. Schematic of audio ADC front-end
Voice ADC operating clock mode
Decimation filter characteristics (audio ADC)
Rev. 03 — 16 February 2005
input signal
2 V (RMS)
s
is performed in two stages. The first stage realizes
Voice ADC
Bit clock frequency (BCKV)
input: 32f
input: 32f
Condition
0 to 0.45f
0.45f
>0.55f
0 to 0.45f
10 k
s
s
VINL,
VINR
s
s
s
s
, 64f
, 64f
s
s
, 128f
, 128f
10 k
V
ref
10 k (0 dB setting)
s
s
or 256f
or 256f
Multichannel audio coder-decoder
V
mgu582
DDA
s
s
= 3.3 V
Figure
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
Word select (WSV)
input
output
Value (dB)
>135
0.01
0.2
70
ADC
3.
UDA1338H
Table
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sin
x
x
4
8 of 54
7.