TPA6211A1-Q1: Why TPA6211A-Q1 still output pop noise when the SHUTDOWN is L?

Hi, 

We will take a look at this and will answer as soon as possible.

Best regards,
Luis Fernando Rodríguez S.

Hi,

Thank you for the provided graphs.

Could you also provide a circuit schematic? This would help us to have a better approach to this issue.

Best regards,
Luis Fernando Rodríguez S.

FYI~

Hi,

I would recommend to try with different input and bypass capacitor values. 

Could you try using 0.1uF or 10nF capacitor as bypass capacitor? Could you tell me if the OP_AMP_DAC is already DC-coupled? What's the approached OP_AMP_DAC level? Could you try removing the C132 capacitor?

Best regards,
Luis Fernando Rodríguez S.

Hi 

The pop noise is occurred when the system power down. 

1. 0.1uF and 10nF bypass capacitor-----No improvement.
2. OP_AMP_DAC directly connect with MCU DAC pin
3. After system power up, OP_AMP_DAC level is about 1/2 VCC
4. remove C132 capacitor----No improvement.

Our customer finds that the pop noise is occurred when VCC discreases to around 1.5V and pop noise has the relationsip with VCC discharge time.

Do you have any other suggestion to avoid the pop noise? TKS~

Hi, 

Thank you for the details on this. Just one more question, does this issue only appear when VDD level decreases? I mean, if you shutdown the device through the SHUTDOWN pin and then power off VDD, is this issue still present? Do you have details about this?

Best regards,
Luis Fernando Rodríguez S.

Hi

if power off VCC after shutdown TPA6211A1-Q1 through the SHUTDOWN pin more than 200ms, there is no pop noise.

because the system needs to meet the quick power off requirement, customer cant not accept 200ms delay.

My customer wants to know:

1. What is the requirement of delay time between shutdown TPA6211A1-Q1 through the SHUTDOWN pin and power off VCC?
2. why the pop noise decrese if the delay time increase?
3. how to solve this pop noise issue at the beginning?

• delay 100ms, pop noise 48mV

• delay 150ms, pop noise 20mV.

• delay 200ms, pop noise 0mV (please ignore 236mV)

Hi,

Thank you for the provided information.

The pop issues always depend of the device being used. In this case, the TPA6211A1-Q1 requires of this 200ms delay in order to ensure these pop issues.

One solution would be increase the VDD capacitance level. This capacitor will discharge slowly. Even if the VDD power is turned off, the capacitor will help to have a high turn off delay at the TPA6211A1-Q1 VDD.

Best regards,
Luis Fernando Rodríguez S.

Hi

would you mind tell me the actual reason of this issue?

Why TPA6211A-Q1 still output pop noise when the SHUTDOWN is L?

why the pop noise decrease if the delay time increase?

TKS~