AK2347B Datasheet, PDF (1/34 Pages) Asahi Kasei Microsystems – Two-way Radio Audio & Sub-Audio Processor

ASAHI KASEI
[AK2347B]
AK2347B
Two-way Radio Audio & Sub-Audio Processor
1. Features
• Audio processing
• TX and RX amplifier
• Pre/De-emphasis circuit
• Compressor and Expander with no external components
• Scrambler and De-scrambler in frequency inversion type (3.388kHz or 3.290kHz)
• Limiter with level adjuster
• Splatter filter for wide and narrow band
• Digital controlled amplifier for microphone, modulator and demodulator sensitivity
• Sub-Audio filter with level adjuster for CTCSS and DCS
• Low power supply operation: 2.7 to 3,3V
• Wide range operating for temperature: -40 to 85 °C
• Oscillator circuit for 3.6864MHz and 3.579545MHz crystal
• Serial control interface operation
• Compact plastic packaging, 24-pin SSOP
2. Description
AK2347B includes audio filter, limiter, splatter filter, compandor, scrambler, which is highly integrated
two-way radio baseband functions for FRS and LMR.
Audio high-pass filter shows a high attenuation in magnitude response characteristics under 250Hz
that supports to eliminate a subaudio tone clearly.
TX limiter for deviation control has a limiting level adjuster by applying a DC voltage via external
components. Splatter filter has the magnitude response for narrowband(fc=2.55kHz) and
wideband(3.0kHz) to meet various regulatory agencies in the world wide.
Compandor is no adjustment type because it includes all parametric components inside the chip.
Scrambler circuit is composed of frequency inversion circuit by double balanced mixer that has
3.388kHz and 3.290kHz carrier clock.
Sub-Audio filter with level adjuster is available for pre- or post-filter for CTCSS and DCS.
There are four signal level adjusters for microphone, modulator and demodulator sensitivity by digital
controlled amplifier (volume).
• Pin Assignment (Top view)
MS1419-E-00
AGNDIN
1
AGND
2
TXINO
3
TXIN
4
EXTIN
5
EXTINO
6
L IM LV
7
MOD
8
VSS
9
SDATA 10
SCLK 11
CSN 12
24
RXIN
23
RXINO
22
F ILT E R O
21
RXOUT
20
DINO
19
DIN
18
RSAOUT
17
TSAOUT
16
VDD
15
XOUT
14
XIN
13
TEST
-1-
2012/05