AK2346A Datasheet, PDF (34/37 Pages) Asahi Kasei Microsystems – Two-way Radio Audio Processor

ASAHI KASEI
[AK2346A]
3) RXA1 Amplifier
This is an operational amplifier suitable for receive gain adjuster and anti-aliasing filter to
eliminate high frequency noise component over 100kHz The gain should be less than 20dB.
The following simplified schematic shows an example of 2^nd order anti-aliasing filter that has
20dB gain and 39kHz cut-off frequency.
_
+
RXA1
11 RXINO
C2
R3
R1 C1
10 RXIN _R2
C3
AGND
C1=0.47uF
C2=33pF
C3=560pF
R1=10kΩ
R2=9.1kΩ
R3=100kΩ
LSI
4) Power supply stabilizing capacitors
To connect capacitors between VDD and VSS pin reduce the ripple and noise included in power
supply. These capacitors are mounted close to the device pins.
7
DVDD
C1
8
VSS1
C1
VDD
C1=0.1μF (Ceramic cap)
C2
C2=10μF (Electrolytic cap)
C2
VSS
9
AVDD
LSI
5) AGND, AGNDIN pin stabilizing
Please decouple to VSS level by the 0.3uF or larger capacitor. These capacitors are mounted
close to the device pins.
14 AGNDIN
C
15 ^AGND
C
C=1μF (Electrolytic capacitor)
MS1289-E-02
LSI
- 34 -
2012/06