CMX639 查看數據表（PDF） - CML Microsystems Plc

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产品描述 (功能)

比赛名单

CMX639

Consumer / Commercial CVSD Digital Voice Codec

CML Microsystems Plc 

CVSD Codec

1.4 External Components

CMX639

Figure 2 Recommended External Connections

R1 Note 1 1MΩ ±10%

C1 Note 2 33pF ±20%

C2 Note 2 33pF ±20%

C3 Note 3 1.0µF ±20%

C4 Note 4

1.0µF

±20%

C5 Note 5

1.0µF

±20%

X1 Note 6, 7 1.024MHz

Table 1 Recommended External Components

Notes:

1. Oscillator inverter bias resister

2. Xtal circuit load capacitor

3. The drive source impedance connected to the coupling capacitor’s input node, rather than the CMX639

ENCODER INPUT pin node, should be should be less than 1kΩ. Output idle channel noise levels will

improve with even lower source impedances driving the coupling capacitor’s input node.

4. Bias decoupling capacitor

5. VDD decoupling capacitor

6. A 1.024MHz Xtal/Clock input will yield exactly 16kbps/32kbps/64kbps internally generated data clock rates

7. For best results, a crystal oscillator design should drive the clock inverter input with signal levels of at least

40% of VDD, peak to peak. Tuning fork crystals generally cannot meet this requirement. To obtain crystal

oscillator design assistance, please consult your crystal manufacturer.

© 2000 Consumer Microcircuits Limited

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CMX639/2

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