TAS5630B: ANALOG INPUTS DC COMMON MODE VOLTAGE SPECIFICATION

Hi David

David Russell3 said:

Is there a defined relationship between the DC common mode ( "Bias" ) voltage present at INPUT_A, _B, _C and _D terminals and the voltage at the VI_CM terminal ?

    They have no connections. VI_CM is used for inner comparator to generate the Drive for MOSFET bridge. Input signal will going through filter and amplify to finally reach comparator.

David Russell3 said:

is there a specification for the input common mode DC bias point ?

    Our device will construct the input bias, so it is better for you to send in no bias signal. Any bias voltage in your signal will be blocked by the capacitor at the input port.

Thanks for your helpful response but have these follow up questions -

Our application requires DC coupling so we cannot use DC blocking capacitors at the inputs. Instead we are designing a direct coupling ckt to drive the differential power amp inputs.

1) What is the range of DC "bias" point voltage at the four input terminals of this device, ( that 5630B will construct ) ?

2) Can we alter this DC "bias" voltage ( common to all input terminals ) with our external driver circuitry if we stay within the operating range ? That is, will the input circuitry reject a small bias point offset voltage common to all input terminals ?

David Russell3 said:

What is the range of DC "bias" point

  It should be around 2.5V.

David Russell3 said:

Can we alter this DC "bias" voltage ( common to all input terminals ) with our external driver circuitry if we stay within the operating range ?

  By staying within operating range, usually shouldn't damage our device. But we won't guarantee the using of removing DC block capacitor, there's no validation test about such kind of using. Also, if there's any different in your own bias voltage, this difference will also amplify by our device, you'll see large DC output.