DS4201

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102099

The VCM output provides the DC bias point to which AC signals are referenced and processed internally.

This output provides a common mode signal that can be used by external circuitry operating from a single

supply. The nominal level of this output is 0.4xVA. VCM cannot support dynamic loading and should be

buffered if AC loading is needed. For typical use, a 0.47

µF capacitor should be connected across VCM

and analog ground for filtering.

NOTE:

See APPENDIX C for additional application information regarding these reference signals.

ANALOG I/O

DS4201 analog I/O consists of two stereo inputs (AUX and MIC) and one stereo output (OUT). Full scale

input and output signal levels supported depend on device operating voltage, the Mixer Unit (MU:UID8)

control setting, and the control setting of the USB audio extension unit (XU:UID9) as listed in the Analog

Performance Characteristics table.

ANALOG INPUTS

Analog signal levels at both the AUX and MIC inputs must be limited to the full scale range supported by

the operating voltage: 0.5 Vrms for 3.3V operation, 1.0 Vrms for 5.0V operation. Additionally, the input

signal must be either AC–coupled to the analog input or centered about the common mode reference level

VCM. For optimal performance, analog input signals should be AC–coupled. External signal attenuation

may be necessary to accommodate 1 Vrms and/or 2 Vrms line level swings that are typically output from

audio equipment.

See APPENDIX C for recommended connection diagrams and example interface

circuits for additional information.

ANALOG OUTPUTS

Analog signal levels at the LOUT and ROUT outputs are DC biased about the common mode reference

output VCM and should be AC–coupled to external circuitry.

Depending on operating voltage, the

DS4201 is designed to produce full–scale output levels of either 0.5 Vrms or 1.0 Vrms, see Analog

Performance Characteristics.

Again, see APPENDIX C for recommended connection diagrams and

example interface circuits for additional information.

POWER

POWER SUPPLY

The three power inputs to the DS4201 provide power to the USB digital (VB), non–USB digital (VD),

and analog circuitry (VA) within the device. These power inputs, combined with a USB suspend power

mode input signal (SPM), provide a range of power configurations. The options include:

• Entire device powered from USB bus power.

• USB circuitry powered from USB bus power, analog and digital circuitry powered from a separate

single source.

• USB circuitry powered from USB bus power, analog circuitry powered from an analog supply, digital

circuitry powered from a digital supply.

NOTE:

USB core specification power requirements must be considered for any power configuration that

consumes power from the USB bus.