- Ask a related questionWhat is a related question?A related question is a question created from another question. When the related question is created, it will be automatically linked to the original question.
Hi Sirs,
We got -3dB corner frequency at 30Hz with TPA6166 EVM. We tried to short the lowpass filter on R1 but not improved.
Is it doable to make flat frequency response from 20Hz to 20kHz with the microphone amp of the TPA6166?
Would you please provide official frequency response specification of the microphone amplifier of the TPA6166 device?
CH1: R1 stuffed, CH2: R2 short
100mV Input signal at SLEEVE, Measured signal at NOUTN, 2.2kR load at MOUTN.
-------------------------------------------------------------------------------------
TPA6166 configuration:
#op i2c Addr Data Comment
w 80 1e 19 #Enable Registers 3
w 80 04 08 #Interrupt Mask Register 1
w 80 05 00 #Interrupt Mask Register 2
w 80 07 bb #Left Headphone Volume Register = +2dB
w 80 08 79 #Right Headphone Volume Register = LR Tracking
w 80 09 c7 #Microphone/Ground Control = +24dB
w 80 12 01 #Reserved Registers
w 80 13 45 #Reserved Registers
w 80 1a 95 #Jack Detect AC Test Settings
w 80 1e 01 #semi auto mode
w 80 1d 80 #Enable Registers 2
-------------------------------------------------------------------------------------
Thank you and Best regards,
Wayne Chen
03/29/2021
Hi Wayne,
Internally the device only has low-pass filters on INx, and below is a summary of the frequency response specs:
Is there any filter at the input of the AP that could affect the measurement?
Best regards,
-Ivan Salazar
Applications Engineer - Low Power Audio & Actuators
Hello Ivan,
We found the LPF (R1, R2 and C3) impacts the frequency response. We can improve amplitude at high band with R1 and R2 shorted, while we can see passband ripple in this case. Here are our comparison:
CH1: R1=R2=1k ohm, CH1-2: R1=R2=short (0 ohm)
Thank you and Best regards,
Wayne Chen
03/31/2021
