cs4412 Cirrus Logic, Inc., cs4412 Datasheet - Page 18

• Manufacturer Part Number: cs4412
• Description: 30 W Quad Half-bridge Digital Amplifier Power Stage Logic
• Manufacturer: Cirrus Logic, Inc.

18
5. POWER SUPPLY, GROUNDING, AND PCB LAYOUT
5.1
5.1.1
5.2
Power Supply and Grounding
The CS4412 requires careful attention to power supply and grounding arrangements if its potential perfor-
mance is to be realized.
Extensive use of power and ground planes, ground plane fill in unused areas and surface mount decoupling
capacitors are recommended. It is necessary to decouple the power supply by placing capacitors directly
between the power and ground of the CS4412. Decoupling capacitors should be as close to the pins of the
CS4412 as possible. The lowest value ceramic capacitor should be closest to the pin and should be mount-
ed on the same side of the board as the CS4412 to minimize inductance effects. The CRD4412 reference
design demonstrates the optimum layout and power supply arrangements.
QFN Thermal Pad
The CS4412 is available in a compact QFN package. The underside of the QFN package reveals a large
metal pad that serves as a thermal relief to provide for maximum heat dissipation. This pad must mate with
an equally dimensioned copper pad on the PCB and must be electrically connected to ground. A series of
thermal vias should be used to connect this copper pad to one or more larger ground planes on other PCB
layers. The CRD4412 reference design demonstrates the optimum thermal pad and via configuration.
Integrated VD Regulator
The CS4412 includes two internal linear regulators, one from the VD supply voltage to provide a fixed
2.5 V
supply to its internal analog blocks. The LVD pin must be set to indicate the voltage present on the VD
pin as shown in
The output of the digital regulator is presented on the VD_REG pin and may be used to provide an exter-
nal device with up to
ulator is presented on the VA_REG pin and must only be connected to the bypass capacitors as shown
in the typical connection diagrams.
If a nominal supply voltage of 2.5 V is used as the VD supply (see the
tions
source. In this configuration, the internal regulators are bypassed and the external supply source is used
to directly drive the internal digital and analog sections.
table on
supply to its internal digital blocks, and another from the VD supply voltage to provide a fixed
High
LVD
Low
page
Table 8
5), the VD, VD_REG, and VA_REG pins must all be connected to the VD supply
3 mA
below.
of current at its nominal output voltage of
Table 8. VD Supply Level Indication
Indicated VD Supply Level
2.5 V or 3.3 V Nominal
5 V Nominal
2.5
Recommended Operating Condi-
V. The output of the analog reg-
CS4412
DS749A1
2.5 V