PCN/PCS Delta Modulation CODEC
6
MX609
3 External Components
XTAL/CLOCK
X1
C2
C1
R1
V
DD
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
DD
CLOCK MODE 1
CLOCK MODE 2
ALGORITHM
DECODER DATA CLOCK
DECODER INPUT
POWERSAVE
DECODER OUTPUT
C5
XTAL
ENCODER DATA CLOCK
ä
ENCODER OUTPUT
ä
DATA ENABLE
BIAS
ENCODER INPUT
C3
MX609DW
V
SS
C4
Figure 2: Recommended External Components for Typical Application
R1
C1
C2
C3
Note 1
Note 2
Note 2
Note 3
1M
33pF
68pF
1.0F
10%
20%
20%
20%
C4
C5
X1
Note 4
Note 5
Note 6, 7
1.0F
1.0F
1.024MHz
20%
20%
Table 4: Recommended External Components for Typical Application
Notes:
1. Oscillator inverter bias resister
2. Xtal circuit load capacitor
3. Encoder input coupling capacitor. The drive source impedance to this input should be less than 100W.
Output idle channel noise levels will improve with even lower source impedance.
4. Bias decoupling capacitor
5. VDD decoupling capacitor
6. 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.
7. 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 MX609 is a Continuously Variable Slope Delta Modulation (CVSD) Codec designed for use in cordless
telephones. The device is suitable for applications in delta multiplexers, switches and phones. Encoder input
and decoder output switched capacitor filters are incorporated on-chip.
Sampling clock rates can be programmed to 16, 32 or 64K bits/second from an internal clock generator or
externally injected in the 8 to 64K bits/second range. The internal clocks are derived from an on-chip
reference oscillator driven by an externally connected crystal. The sampling clock frequency is output for the
synchronization of external circuits.
The encoder has an enable function for use in multiplexer applications. When not enabled the encoder output
remains in a high-impedance “tri-state” mode.
Companding circuits may be operated with an externally selectable 3- or 4-bit algorithm. The device may be
put in standby mode when Powersave is selected.
1998
MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
Doc. # 204800069.005
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
All Trademarks and service marks are held by their respective companies.
CMLMICRO [ CML MICROCIRCUITS ]
