Analog and audio

Posted on June 13, 2017 at 16:45On the steval-mki138 MEMS microphones dev kit, using the STAudioHub firmware and tools, I am observing a significant time drift between 2 developments kits acquiring the same audio signal at the same time. I am now looking for ways of improving this situation. Is the STAudioHub firmware source code available somewhere? Did anybody try difference hardware or software clock configuration? Any hint would help.

Posted on June 09, 2017 at 05:47We are seeing some of our opamps failing, outputting the VCC rail regardless of input!The input signal is a BLDC fan current sense resistor and cell a is a non-inverting gain of 3x.Our sleep circuit was implemented incorrectly, during sleep Vcc is actually 1.5V instead of 0V, can this damage this part (note: other pins should be at 0V until 3.3V is applied when woken)?

Posted on June 02, 2017 at 08:40Hello ,Could you kindly recommend me any STM  kit that can be applicable for MEMS microphone ?This kit should be USB interfaced with PC, my plan is to connect it to VL812 USB 3.0 Hub Controller .Is it possible to make PDM interface with STM kit?

Posted on May 24, 2017 at 10:06We use osxAcousticEC library on STM32F401CBY6.For only one MCU, we can use OSX LicenseWizard to get license and this function is ok.But we are going to mass production, could you tell me how to batch obtain license? Thanks.

Posted on May 26, 2017 at 23:10HiLooking at the TDA7492P, but this seems to apply to the TDA749xxx devices as I checked those data sheets too.SVCC (35) and SVSS (36). Is the schematic correct? Do I simply connect the two with a cap, but neither to power or ground?PGND (18). Should this be connected to ground? Schematic shows it is bypassed to VDDPW(19), but otherwise not connected.I am asking this as i feel the pin naming is not well chosen, generally, if a pin is named 'xxGND' it is connected to ground. Just sayin ;)

Posted on May 24, 2017 at 10:10We use osxAcousticEC library on STM32F401CBY6.For only one MCU, we can use OSX LicenseWizard to get license and this function is ok.But we are going to mass production, could you tell me how to batch obtain license? Thanks.

Posted on May 22, 2017 at 15:59Thanks a lot

Posted on May 15, 2017 at 09:10I am having problems, with a TDA7491HV design (taken directly from the http://www.st.com/resource/en/datasheet/tda7491hv.pdf - Figure 50) and although it is working, the output inductors are getting very hot. Hot means ~85C with an ambient temp of 15C.I have read elsewhere on this forum that https://community.st.com/message/155712-re-tda4791lp-no-output-solved?commentID=155712#comment-155712 has use (with success) a 'filterless' output stage with the TDA7491LP.Does anyone know if this approach is feasible for the TDA7491HV? There is no equivalent tohttp://www.st.com/resource/en/datasheet/tda7491lp.pdf in the TDA7491HV datasheet.Best regards, Martin

Posted on May 02, 2017 at 21:14How to make a code from 2 channels for conversion.please!!

Posted on June 12, 2016 at 19:41I've got a TDA7491LP design that I cannot seem to make function. I've followed the ''Applications Circuit for class D amplifier'' example circuit (Figure 26 on the datasheet). I'm powering the amplifier with a 10V switchmode supply.Some measurements from the board, all referenced to the circuit common (where SGND and PGND are connected): MUTE (pin 21) at 3.5VSTANDBY (pin 20) at 3.5VVDDPW (pin 19) and VDDS (pin 26) are both reading 3.2V.PVCC is supplied with 10VSVCC (pin 35) at ~10VVSS (pin 36) reads ~6.5VVREF (pin 34) at ~1.8VSYNCLK output (pin 25) reading ~4V square wave of ~630kHzI've got the inputs configured in single-ended mode; INNA and INNB are each conected through individual 470nF capacitors to my circuit common. I'm supplying a 1Vp-p 1kHz sine wave on INNA.  I should be seeing a PWM waveform at OUTPA/OUTPN but both these pin sets are reading about 200mV; there is no PWM activity at all.Now I'm a little confused; SVCC is called ''signal po

Posted on April 24, 2017 at 13:14I am using L9823 in my design to drive the outputs. I also want it to behave as input so that I can connect IO module. How can I use it as input?

Posted on April 02, 2017 at 02:40I have a part in a car infotainment system that I can't identify. It has ST branding, but I can't figure out what it is. Can anyone help me? I've uploaded 2 shots of the same part. Thank you.

Posted on March 18, 2017 at 17:57How to use EVALSTPM34 kit??

Posted on March 20, 2017 at 11:09Hi,I want to record some audio signals using your Evaluation Kit STEVAL-MKI126V1 + MKI129V3 connected to my laptop through the MKI138V1.I've installed APWorkbench on Windows 64bit running on Parallels Desktop.How to stored data coming from six microphone (2 on board from STEVAL-MKI126V1 + 4 on STEVAL-MKI129V1)?What I needed is six different .wav / .csv / .mp3 files corresponding to each microphone.Thanks and Regards,Mayuri

Posted on March 07, 2017 at 21:42hi all,this nice AMP IC is quite easy to setup and switch on trough i2c.Diagnostic to check for speaker in short, open etc, is available trough i2c before i2c amp stage power up, and should be still available also after power up.Btw, once amp stage has been powered up with diag bit enabled, i get always the same 4 bytes diag info, even generating some shorts, nothing change in the diagnostic 4 bytes info.If any help, or any link for a sample driver, really welcome.Regards,angelo

Posted on March 06, 2017 at 04:31Hello, I have a car amplifier, the chip is used FDA4100LV, I need FDA4100LV typical circuit diagram, who can give me a copy of it? Thank you。

Posted on March 04, 2017 at 17:10I'm using a simple capacitance to frequency converter with a ts555 to measure water level. After installation, I notice a large drift, so I returned the circuit to the lab to diagnose the problem. To eliminate the sensor as source of problem, I replaced it with a fixed (stable) value. The drift seemed temperature related, so I tried to change each component's temperature separately, and was surprised that the power supply decoupling cap seemed the problem. I realized that probably the value was too low, so I changed with with several larger values, of different technologies, but the sensitivity didn't really go away.I would like to simulate the circuit in Spice, but couldn't find a specific model for ST's TS555 version.Questions: Where can I find the Spice model for the TS555?Any suggestions to reduce the temperature sensitivity?Screenshot of the oscillator (C3 was changed to 22nF, then 100nF. T5/T6 are the terminals for the level sensor, replaced by a

Posted on February 15, 2017 at 21:38I can use one SAI RxTx channel  or Two separate SAI ports,  providing independent Rx and Tx channels.Which solution supplies the best HD stereo audio quality ? (stereo and bass channel would be great)The Speaker drive can be separated from the Audio codec but I am all ears on any suggestions.My processor board is based on the STM32F7 series processors I am developing my own low level drive software, to facilitate a smaller code footprint and the highest quality seamless Stereo Audio I/O.The design is working toward a Skype/Gypsy Audio interface, and to reproduce reasonable quality music.Which software protocol is better ?  SAI,  I2S, PCM , SPDIF ?I see the SAI port has an 8 byte fifo shared between Rx and TX channels. how can that be full duplex ?which Codec can someone suggest ?  for High quality Stereo..do we need a separate drive ? 10W is huge for this...#audio-drive #audio-codec

Posted on January 24, 2017 at 10:22As we know, TDA7498E is designed for Audio amplifier application.  But we are interested in using it for DC amplifier application.In our application, an inductance coil is connected to amplifier output. This load is up to 24VDC / 3A max, so Class D amplifier is idea for it.But the operating frequency range is from 0Hz-100Hz, which is different with Audio application. Can we just remove the DC-block capacitor from the input circuit, and use TDA7498E in this DC amplifier application?#tda7498e

Posted on January 19, 2017 at 21:47I can not find the polarity for the default bridge connection (OCFG=00,  FFX1A -> OUT1A, FFX1B -> OUT1B, FFX2A -> OUT2A,FFX2BA -> OUT2B)On my test result, OUT1A and OUT2A should connect to the positive pole of speaker,                              OUT1B or OUT2B should connect to the negative pole of speaker.I'm appreciated if you guys can help me to confirm the connection.

Posted on December 23, 2016 at 13:41Hi... ST Team...We are using TSH122ICT video amplifier with our designs. To amplify CVBS Output signal. But we are not getting any output at the TV. please let us know what may be the failure cause.Below is the circuit i have used in my design...Please provide us the solution as soon as possible.#tsh122ict-video-amplifier-not-working

Posted on January 16, 2017 at 09:55What is the lowest value of series resistor that I can use to maintain stability of this amplifier. I would like to use a series resistor of 200R to 1K to a load that will have some variable capacitance. I need to use a low power op-amp, if you chose to suggest another..#op-amp-stability

Posted on January 03, 2017 at 03:43Hi, Recently,I use STA309A in my project doing some cross-over algorithms.On the first page of STA309A it says '192 kHz internal processing sample rate',is that to say when I feed 44.1K/88.2K/176.4K IIS signal into the chip,it still runs at 192k internal processing sample rate(some sort of resampling),or it runs at 176.4K(no resampling)? I want to keep the same cross-over parametersultilizing 309`s internal BQ filters in different input samping rate,is it necessary to generate two BQ filter coefficient tables for 176.4k and 192k internal sampling rate respectively?Besides,I manually do the arithmatics for the BQ coefficients and notice APWorkbench give me these coefficients base on only 192k internal sampling rate.I still remember my project with STA350BW years ago,it has 3 coefficient banks for different internal sampling rate(64k,88.2k and 96k),I wonder if STA309A has some register banks like STA350 has.One more question,why STA309A eliminates the

Posted on December 23, 2016 at 11:48Hi,Could you please provide the reference design of TSH122ICT ? Also please share the layout guidelines for TSH122ICT. Regards,Azlum#tsh122ict

Posted on December 02, 2016 at 11:57Hi, Some quick questions about the STA311B. How does the quality of the clock at XTI affect the FFX output and ultimately performance of the system? Do you have any reference design, figures or charts showing potential benefits of power supply error correction with a ADC. Is the IC programable with a FD2233D and APWorkBench? Many thanks! #sta311b