Delta Modulation CODEC
6
MX619
3 External Components
XTAL/CLOCK
X1
C2
C1
R2
R1
V
DD
1
2
3
4
5
6
7
8
9
10
11
22
21
20
19
V
DD
CLOCK MODE 1
CLOCK MODE 2
ALGORITHM
DECODER DATA CLOCK
DECODER INPUT
DECODER FORCE IDLE
POWERSAVE
N/C
DECODER OUTPUT
N/C
C5
XTAL
N/C
ENCODER DATA CLOCK
ENCODER OUTPUT
ENCODER FORCE IDLE
DATA ENABLE
N/C
BIAS
ENCODER INPUT
C3
MX619J
18
17
16
15
14
13
12
V
SS
C4
Figure 2: Recommended External Components for Typical Application
R1
R2
C1
C2
Note 1
Note 2
Note 3
Note 3
1MΩ
Selectable
33pF
68pF
±10%
±20%
±20%
C3
C4
C5
X1
Note 4
Note 5
Note 6
Note 7, 8
1.0µF
1.0µF
1.0µF
1.024MHz
±20%
±20%
±20%
Table 4: Recommended External Components for Typical Application
Notes:
1. Oscillator inverter bias resister.
2. Xtal Drive limiting resistor.
3. Xtal circuit load capacitor.
4. Encoder input coupling capacitor. The drive source impedance to this input should be less than 100Ω.
Output idle channel noise levels will improve with even lower source impedance.
5. Bias decoupling capacitor
6. V
DD
decoupling capacitor
7. A 1.024MHz Xtal/Clock input will yield exactly 16/32/64kbps data clock rates. Xtal circuitry shown is in
accordance with MX-COM’s Xtal Oscillator Application Note.
8. For best results, a crystal oscillator design should drive the clock inverter input with signal levels of at
least 40% of V
DD
, peak to peak. Tuning fork crystals generally cannot meet this requirement. To obtain
crystal oscillator design assistance, please consult you crystal manufacturer.
4 General Description
The MX619 is a Continuously Variable Slope Delta Modulation (CVSD) Codec designed for use in military
communications systems. This device is suitable for applications in military delta multiplexers, switches and
phones. The MX619 is designed to meet EUROCOM D1-IA8 specifications.
Encoder input and decoder output filters are incorporated on-chip. Sampling clock rates can be programmed
to 16, 32, or 64kbps from an internal clock generator or externally injected in the 8 to 64kbps range. The
sampling clock frequency is output for the synchronization of external circuits.
The encoder has an enable function for use in multiplexer applications. Encoder and Decoder forced idle
capabilities are provided forcing 10101010…pattern in encode and a V
DD
/2 bias in decode. The companding
circuit may be operated with an externally selectable 3- or 4-bit algorithm. The device may be placed in
standby mode by selecting Powersave. A reference 1.024MHz oscillator uses an external clock or crystal.
2000
MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
Doc. # 20480189.002
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
All Trademarks and service marks are held by their respective companies.
CMLMICRO [ CML MICROCIRCUITS ]
