CS4299-BQZR Cirrus Logic Inc, CS4299-BQZR Datasheet - Page 39

• Manufacturer Part Number: CS4299-BQZR
• Description: IC AC97 Codec With SRC
• Manufacturer: Cirrus Logic Inc

DS319-BQPP2
6.3
The AFLT1 and AFLT2 pins must have a 1000 pF
NPO capacitor to analog ground. These capacitors
provide a single-pole low-pass filter at the inputs to
the ADCs. This makes low-pass filters at each ana-
log input pin unnecessary.
The REFFLT pin must have a 1 µF and a 0.1 µF ca-
pacitor connected to analog ground with a short,
wide trace to this pin (see Figure 21 in Section 8,
Grounding and Layout, for an example). The 1 µF
capacitor must not be replaced with any value high-
er than 1 µF. No other connection should be made,
as any coupling onto this pin will degrade the ana-
log performance of the CS4299-BQ. Likewise, dig-
ital signals should be kept away from REFFLT for
similar reasons.
The Vrefout pin is typically 2.3 V and provides a
common mode signal for single-supply external
circuits. Vrefout only supports light DC loads and
should be buffered if AC loading is needed. For
typical use the Vrefout pin should have a 1 µF and
a 0.1 µF capacitor connected to analog ground.
Miscellaneous Analog Signals
Y5V
0.1µF
DGND
+12VD
+
ELEC
10µF
Figure 19. Voltage Regulator
1
IN
MC78M05CDT
GND
2
6.4
The power supplies providing analog power should
be as clean as possible to minimize coupling into
the analog section which could degrade analog per-
formance. The analog power pins, AVdd1 and
AVdd2, supply power to all the analog circuitry on
the CS4299-BQ. The +5 V analog supply should be
generated from a linear voltage regulator (7805
type) connected to a +12 V supply. This helps iso-
late the analog circuitry from noise typically found
on +5 V digital supplies. A typical voltage regula-
tor
MC78M05CDT +5 V regulator is shown in
Figure 19. The digital power pins, DVdd1 and
DVdd2, should be connected to the same digital
supply as the controller AC-link interface. The dig-
ital interface on the CS4299-BQ may operate at ei-
ther +3.3 V or +5 V and proper connection of these
pins will depend on the digital power supply of the
controller.
6.5
See Section 11 for a CS4299-BQ reference design.
OUT
circuit
Power Supplies
Reference Design
3
Y5V
0.1µF
for
+5VA
AGND
+
ELEC
10µF
analog
power
CS4299-BQ
CS4299-BQ
using
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a