CMX138 CML Microcircuits, CMX138 Datasheet - Page 9

• Manufacturer Part Number: CMX138
• Description: Audio Scrambler and Sub-Audio Signalling Processor
• Manufacturer: CML Microcircuits

Audio Scrambler and Sub-Audio Signalling Processor
5
Notes:
1
2
© 2008 CML Microsystems Plc
R1
R2
R3
R4
R5
R6
R7
X1
External Components
X1 can be a crystal or an external clock generator; this will depend on the application. The tracks
between the crystal and the device pins should be as short as possible to achieve maximum stability
and best start up performance.
R2 and R3 should be selected to provide the desired dc gain of the discriminator input, as follows:
The gain should be such that the resultant output at the DISCFB pin is within the discriminator input
signal range specified in 7.11.2. If the DISCIN2 pin is selected the gain becomes:
(assuming that R3 and R4 are both connected to the same input signal).
TBD
100kΩ
100kΩ
100kΩ
100kΩ
100kΩ
100kΩ
6.144MHz
See note 1
DVss
C14 C15
C13
Resistors ±5%, capacitors and inductors ±20% unless otherwise stated.
C12
R10
C8
C11
AV
Figure 2 CMX138 Recommended External Components
SS
C10
C9
MICFB
R8
R9
R10
R11
R12
SYSCLK
R9
CDATA
RDATA
TxENA
DV
SCLK
DV
IRQN
V
CSN
X1
DEC
DD
MOD
SS
100kΩ
TBD
10kΩ
10kΩ
10kΩ
10
11
12
13
14
1
2
3
4
5
6
7
8
9
⏐GAIN
⏐GAIN
CMX138
Disc
Disc
Page 9
⏐ = R2 / (R3//R4)
C7
28
27
26
25
24
23
22
21
20
19
18
17
16
15
⏐ = R2 / R3
R8
C1
C2
C3
C4
C5
C6
C7
C8
DISCFB
DISCIN1
DISCIN2
AUDIO
AuxADC
MICN
CLKSEL
AuxDAC
V
AV
MICP
RxENA
DV
AV
BIAS
SS
DD
SS
10nF
100pF
TBD
TBD
100nF
10μF
10nF
100pF
R1
R2
R7
DV
SS
R3
R4
C5
C1
C2
C3
C4
R12
R11
R5
C9
C10
C11
C12
C13
C14
C15
C16
AV
SS
39pF
39pF
10μF
10nF
10nF
10μF
10nF
100nF
C16
C6
R6
D/138_FI1.0/5
CMX138