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Part Number: TLV320DAC3203
Hi~
I test the following code in audio precision (Digital serial: out ; analog: in)
What I got the frequency response is -6dB and group delay is less than datasheet suggest.(Datasheet said group delay(Typical?) =13/Fs in filter C case.
The group delay in my measurement is 0.33ms~11/Fs?!.)
To make sure, is there any possible wrong in my code? (Measurement setting in AP seems alright because when testing other codec it is fine.)
Ps. I use 4M crystal input to MCLK pin. Codec output BCLK and WCLK clock into Audio Precision digital serial port. The whole code is for 32k sample rate application.
{0x00, 0x00}, // 0. Initialize to page 0 {0x01, 0x01}, // 1. Initialize the device through software reset {0x04, 0x03}, // 2. Set PLL_CLKIN as MCLK and CODEC_CLKIN as PLL_CLK {0x05, 0x93}, // 3. Power up PLL, set PLL divider P=1 and PLL divider R=3 {0x06, 0x07}, // 4. Set PLL divider J=7 {0x07, 0x00}, // 5. Set PLL divider D=0000 {0x08, 0x00}, // 6. {0x0b, 0x83}, // 7. Power up and set NDAC divider = 3 {0x0c, 0x87}, // 8. Power up and set MDAC divider = 7 {0x0d, 0x00}, // 9. Set DOSR = 128 MSB //for32Khz {0x0e, 0x80}, //10. Set DOSR = 128 LSB //for32Khz {0x1b, 0x3c}, //11. Set I2S interface, Word length 32 bit, BCLK output, WCLK output {0x3c, 0x11}, //12. DAC mode to PRB_P17 {0x1d, 0x05}, //13. BDIV_CLKIN = DAC_MOD_CLK {0x1e, 0x82}, //14. Power up and set BCLK N divider = 2 //for 32KHz {0x00, 0x01}, //15. Select page 1 {0x01, 0x08}, //16. Disable internal crude AVdd in presence of external AVdd supply {0x02, 0x00}, //17. Enable master analog power control {0x7b, 0x01}, //18. Set the REF charging time to 40ms {0x0a, 0x00}, //19. Set the input common mode to 0.9V and output common mode for headphone to input common mode {0x0c, 0x08}, //20. Route left DAC & INL to HPL {0x0d, 0x08}, //21. Route right DAC & INR to HPR {0x03, 0x00}, //22. Set the DAC PTM mode to PTM_P3 {0x04, 0x00}, //23. {0x10, 0x00}, //24. Set the HPL gain to 0dB {0x11, 0x00}, //25. Set the HPR gain to 0dB {0x14, 0x29}, //26. HP soft stepping settings for optimal pop performance at power up. Rpop used is 6k with N = 6 & soft step = 20usec {0x09, 0x30}, //27. Power up HPL and HPR drivers //#----------- Wait for 2.5 sec for soft stepping to take effect //#----------- else read page 1, register 63d, D(7:6). When = “11” soft-stepping is complete {0x00, 0x00}, //28. Select page 0 {0x44, 0x00}, //29. DRC Control Register 1 , disable DRC {0x3f, 0xd6}, //30. Power up the left and right DAC channels and route the left channel I2S data // to left channel DAC and right channel I2S data to right channel DAC {0x40, 0x00} //31. Unmute the DAC digital volume control
Thanks.
Y.W. Fan
In reply to Ivan Salazar:
Hi, Ivan :
Thanks for your quick reply.
Originally I thought it might be ok using 31.25k for test because AP receive clock from codec. Hence the whole system work base on one clock.
I will test it and response to you.
Best regard,
In reply to user5180027:
Y.W.How are you performing the measurement that gives you -6dB result?Isn't it that the measurement gives -6dbV? The output of TLV320DAC3203 should be around 0.5Vrms which is around -6dbV.Best regards,-Ivan SalazarApplications Engineer - Low Power Audio & Actuators
Hi~Ivan
I use -20dBFS sine sweep signal from Audio Precision digital serial I2S into codec. Codec then output analog into Audio Precision analog input port.
Since codec common mode has 0.9V DC. I turn on Audio Precision DC filter.
The 3 repeat measurement of frequency response (dB(Vrms/Fs)) is follow(The RMS level is around 0.05Vrms):
So, is anything wrong? After DC filter, the RMS level is far from 0.5Vrms.
Best Regards,
Y.W.I don't think there is anything wrong.We're talking about the same, dB(Vrms/FS) is taking 1Vrms as full scale reference. and dBV is also taking 1Vrms as reference.-6dBV and -6dB(Vrms/FS) is 0.5Vrms. The full scale analog output of TLV320DAC3203 is 0.5Vrms.
Best regards,-Ivan SalazarApplications Engineer - Low Power Audio & Actuators
Hi~ Ivan
Thanks for your support and guidance. That help a lot.
I will check again for sure.
On the other hand, do I need to concern the mismatch of group delay? Because my measurement of group delay is less than the value 13/Fs. Does this mean typical value?
and AP measurement is