Manual

CDB47xxD Differential Schematic Descriptions

CDB47xxx User’s Manual

6.3 CDB47xxD Differential Schematic Descriptions

6.3.1 CDB47xxxD Block Diagram

Figure 6-13 shows the CDB47xxxD block diagram

6.3.2 Daughtercard Connectors

Figure 6-15 shows the schematic for the daughtercard connectors on the CDB47xxxD board.

See section Section 6.2.2 for description of circuitry.

6.3.3 Digital Audio and Control Connectors

Figure 6-16 shows the schematics for the digital audio and control connectors on the CDB47xxxD board.

See section Section 6.2.3 for description of circuitry.

6.3.4 Memory

Figure 6-17 shows the schematic for the Flash memory devices.

See section Section 6.2.4 for description of circuitry.

6.3.5 Microphone Preamplifier

Figure 6-18 shows the microphone preamplifier for the CDB47xxxD.

See section Section 6.2.5 for description of circuitry.

6.3.6 Power

Figure 6-19 shows the schematics for power on the CDB47xxxD board.

See section Section 6.2.6 for description of circuitry.

6.3.7 Input Filters

Figure 6-20 shows the input CDB47xxxD. Each channel of the CS470xx is differential and input has its

own input filter that consists of a current limiter, an AC-coupling capacitor (10 F), and an anti-aliasing

capacitor (2200 pF) which is not populated. The current limiter is scaled to make the CDB47xxxD capable

of accepting analog signals of up to 4V

RMS differentially.

6.3.8 Output Filters

Figure 6-21 shows the output filters for the CDB47xxxD.

Each channel of the CS470xx is differential and is fed to an op-amp that converts the differential signal

into a single-ended output with a maximum swing of 2 V

RMS

Each output has a series resistor (560 ) to provide a voltage drop when the muting transistor is enabled,

and a mute transistor that will pull the output low when the mute control signal is enabled. The series

resistor is small enough that it does not affect the signal in normal operation, assuming a load of at least

5k is connected to the analog output of the board.