ASAHI KASEI
[AK2360A]
AK2360A
Scrambler IC for two-way radio
Features
Frequency inversion type scrambler for a voice encryption two-way radio
High quality decoded voice: S/N=47dB(Typ), S/(N+D)=50dB(Typ)
Allowing selection of an inverted frequency (3.397kHz or 3.039kHz) and voice passage band
Scrambler bypass function included
Based on 5.3125MHz (1/4 for 21.25MHz) external clock supply
Operating voltage:
2.6V to 3.3V
-30°C to +85°C
Operating temperature:
Package:
8-pin SON
Block Diagram
AIN
CNT
AOUT
AAF
LPF1
DBM
LPF2
SMF
BUF
DIV
AGND
Power down
at “CNT=L”
+
SLCT
CLK
VDD
MS0393-E-00
-1-
VSS
AGND
+
2005/05
ASAHI KASEI
[AK2360A]
Contents
- Features .................................................................................................. 1
- Block Diagram ......................................................................................... 1
- Contents ................................................................................................. 2
- General Description ................................................................................. 3
- Circuit Configuration ............................................................................... 3
- Pin Functions .......................................................................................... 4
- Absolute Maximum Ratings ...................................................................... 5
- Recommended Operating Conditions .......................................................... 5
- Digital DC Characteristics ........................................................................ 5
- Clock Input Characteristics ....................................................................... 5
- Current Consumption ............................................................................... 6
- Analog Characteristics ............................................................................. 6
- Recommended External Application Circuits .............................................. 7
- Package .................................................................................................. 9
MS0393-E-00
-2-
2005/05
ASAHI KASEI
[AK2360A]
General Description
The AK2360A is a radio scrambler IC device suitable for half-duplex communication. As the scrambler
method, a simple frequency inversion method is used in which audio signal components are inverted about the
carrier frequency by using the double balanced mixer (DBM).
The inverted frequency and voice passage band can be changed according to the input to the SLCT pin. The
scrambler can be bypassed by using the CNT pin, and part of the circuit blocks is placed in the power-down
state accordingly.
A signal-to-noise ratio of 40dB or more and a distortion of 43dB or more can be obtained by inserting filters
before and after DBM as shown in the block diagram, therefore allowing less sound quality deterioration when
the scrambler is used.
Pin assignments (Top view)
AGND
AIN
VSS
CLK
1
2
3
4
8
7
6
5
AOUT
CNT
SLCT
VDD
Circuit Configuration
Block
AAF
LPF1
DBM
LPF2
SMF
BUF
DIV
AGND
Function
Active low-pass filter to prevent aliasing noise generated in the following switched capacitor
filter (SCF) block
Low-pass filter for limiting the band of the audio signal input from the AIN pin
Double balanced modulator for performing frequency inversion.
be changed according to the input level on the SLCT pin.
The carrier frequency can
Low-pass filter for removing upper wave components generated by mixing by DBM
Smoothing filter for removing harmonics components generated in LPF2 and clock
components
Buffer circuit for adjusting the level of the clock signal input from the CLK pin
Divides the clock signal and generates a clock signal for the SCF circuit and the carrier
frequency for DBM.
A block for generating the reference voltage (1/2VDD) of the internal analog circuit
MS0393-E-00
-3-
2005/05
ASAHI KASEI
[AK2360A]
Pin Functions
Pin No.
1
2
3
4
5
Pin name
AGND
AIN
VSS
CLK
VDD
Pin type
AO
AI
PWR
AI
PWR
Function
Analog ground output pin
A capacitor is connected to this pin to stabilize the analog ground level.
Audio signal input pin
Negative power supply pin
Apply 0V.
Clock signal input pin
See "Recommended External Application Circuits".
Positive power supply pin
Connect this pin to a power supply ranging from 2.6V to 3.3V with less noise.
Connect a bypass capacitor of 0.1µF or higher between this pin and the VSS pin.
Carrier frequency switching pin
This pin changes the carrier frequency and voice passage band for the scrambler.
Input level
High
Low
Carrier frequency
3.376kHz
3.020kHz
Voice passage band
290Hz to 3090Hz
260Hz to 2760Hz
*1)
Scrambler bypass pin
This pin causes the AAF block through LPF2 block to be bypassed.
bypassed, these blocks are placed in the power-down state.
7
CNT
DI
Input level
High
Low
Setting
Scrambler enables.
Scrambler bypasses.
*1)
8
AOUT
AO
Audio signal output pin
*2)
When
6
SLCT
DI
Note)
A:
Analog,
D:
Digital,
PWR:
Power,
I:
Input,
O:
Output
*1)
*2)
A pull-up resistor of 50kΩ or more is included.
Load impedance > 10kΩ, load capacitance < 50pF
MS0393-E-00
-4-
2005/05
ASAHI KASEI
[AK2360A]
Absolute Maximum Ratings
Parameter
Power supply voltage
Ground level
Input voltage
Input current (excluding power supply pin)
Storage temperature
Note) All voltages are relative to the VSS pin.
Caution)
Symbol
VDD
VSS
V
IN
I
IN
T
stg
Min.
-0.3
0
-0.3
-10
-55
Max.
4.6
0
VDD+0.3
+10
130
Unit
V
V
V
mA
°C
If the device is used in conditions exceeding these values, the device may be destroyed.
Normal operations are not guaranteed in such extreme conditions.
Recommended Operating Conditions
Parameter
Symbol
Condition
Min.
-30
2.6
3.0
1/2VDD
Typ.
Max.
85
3.3
Unit
°C
V
V
Operating temperature
Ta
Operating power supply
VDD
voltage
Analog reference voltage
AGND
Note) All voltages are relative to the VSS pin.
Digital DC Characteristics
Parameter
High level input voltage
Low level input voltage
High level input current
Low level input current
Pull-up resistance
Symbol
V
IH
V
IL
I
IH
I
IL
R
UP
Condition
SLCT, CNT
SLCT, CNT
V
IH
=VDD
SLCT, CNT
V
IL
=0V
SLCT, CNT
SLCT, CNT
Min.
0.8VDD
0.2VDD
10
-66
50
Typ.
Max.
Unit
V
V
µA
µA
kΩ
Clock Input Characteristics
Parameter
Clock cycle
Input amplitude
Symbol
T
WP
V
CLK
Condition
CLK
CLK
0.2
Min.
Typ.
188
VDD-0.1
Max.
Unit
ns
V
PP
Remarks
f=5.3125MHz
Clipped sine
wave
MS0393-E-00
-5-
2005/05
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