ADAU1452 Datasheet, PDF (178/180 Pages) Analog Devices – SigmaDSP Digital Audio Processor

ADAU1452/ADAU1451/ADAU1450
Data Sheet
EXAMPLE PCB LAYOUT
Several external components, such as capacitors, resistors, and
a transistor, are required for proper operation of the device.
An example of the connection and layout of these components
is shown in Figure 88. Thick black lines represent traces, gray
rectangles represent components, and white circles with a thick
black ring represent thermal via connections to power or ground
planes. If a 1.2 V supply is available in the system, the transistor
circuit (including the associated 1 kΩ resistor) can be removed,
and 1.2 V can be connected directly to the DVDD power net,
with the VDRIVE pin left floating.
The analog (AVDD), PLL (PVDD), and interface (IOVDD)
supply pins each have local 100 nF bypass capacitors to provide
high frequency return currents with a short path to ground.
The digital (DVDD) supply pins each have up to three local
bypass capacitors, as follows:
• The 10 nF bypass capacitor, placed closest to the pin, acts
as a return path for very high frequency currents resulting
from the nominal 294 MHz operating frequency of the
DSP core.
• The 100 nF bypass capacitor acts as a return path for high
frequency currents from the DSP and other digital circuitry.
• The 1 μF bypass capacitor is required to provide a local
current supply for sudden spikes in current that occur at
the beginning of each audio frame when the DSP core
switches from idle mode to operating mode.
Of these three bypass capacitors, the most important is the 100 nF
bypass capacitor, which is required for proper power supply
bypassing. The 10 nF and 1 μF capacitors can optionally be used
to improve the EMI/EMC performance of the system.
10μF IOVDD
CURRENT
RESERVOIR
10μF
10μF
10μF DVDD
CURRENT
RESERVOIR
DVDD REGULATOR
100nF
BYPASS
1μF
100nF
10nF
1μF
BYPASS
100nF
BYPASS
10nF
BYPASS
DGND
IOVDD
VDRIVE
PIN 1
AGND
AVDD
100nF
BYPASS
100nF
DVDD
10μF PVDD
CURRENT
RESERVOIR
10μF
100nF
BYPASS
150pF
100nF
4.3kΩ
PLL LOOP FILTER
100nF
BYPASS
PGND
PVDD
PLLFILT
DGND
IOVDD
ADAU1452/
ADAU1451/
ADAU1450
(TOP VIEW)
10nF
100nF
1μF
10nF
BYPASS
100nF
BYPASS
1μF
BYPASS
Figure 88. Supporting Component Placement and Layout
Rev. C | Page 178 of 180
100nF
BYPASS
IOVDD
DGND
100nF
BYPASS
10nF
100nF
1μF
10nF
BYPASS
100nF
BYPASS
1μF
BYPASS