MAX5556 Datasheet, PDF (8/19 Pages) Maxim Integrated Products – Low-Cost Stereo Audio DACs

Low-Cost Stereo Audio DACs
SDATA
SCLK
LRCLK
MCLK
SERIAL
INTERFACE
MAX5556–MAX5559
INTERPOLATOR
INTERPOLATOR
Figure 2. Functional Diagram
125
100
75
50
25
VDD
SIGMA-DELTA
MODULATOR
DAC
INTERNAL
REFERENCE
SIGMA-DELTA
MODULATOR
DAC
GND
SAFE OPERATING REGION
ANALOG
LOWPASS
FILTER
ANALOG
LOWPASS
FILTER
OUTL
BUFFER
OUTR
BUFFER
3
5
10
15
20
25
Figure 3. Load-Impedance Operating Region
LOAD RESISTANCE R_L (kΩ)
Integrated Analog Lowpass Filter
The DAC output of the sigma-delta modulator is fol-
lowed by an analog smoothing filter that attenuates
high-frequency quantization noise. The corner frequen-
cy of the filter is approximately 2 x f_S.
Integrated Analog Output Buffer
Following the analog lowpass filter, the analog signal is
routed through internal buffers to OUTR and OUTL. The
buffer can directly drive load resistances larger than
3kΩ and load capacitances up to 100pF (Figure 3).
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