https://e2e.ti.com/support/amplifiers-group/amplifiers/Find answers, share knowledge, solve problems with fellow engineers.en-USTelligent Community 13https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1649573/opa814-simulate-gain-stability-for-ninv-opampTue, 26 May 2026 19:16:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:f0bd1a43-82ec-4af4-a1c1-203920c54e5eDennis BrownPart Number: OPA814 I have a design that uses the OPA814 configured as a unity gain buffer but it wants to oscillate when the feedback resistor is a 0 ohm short (the other resistor to ground being an open). It will stop oscillating once a 50ohm resistor is installed in the feedback. Seems there is limited phase margin here but I would like to know more about the analysis from tina. In tina, how does one simulate open loop stability or closed loop stability for an opamp configured in a noninverting format? Would like to see gain (dB) and phase margin (deg). Closed loop gain/phase is easier as this is what is in my tina file attached. There is nothing obviously wrong in closed loop format here to me. There are a couple videos on the TI website that show similar concepts but not necessarily like this problem. If you have a link to something similar please post it. For the record the attached file does not show any sort of oscillation but I just want to know how to extract out gain/phase information under AC analysis so I have a better grasp on the problem. OPA814_TINA_stability.TSCOPA814https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1649567/tlv9001-pinout-tlv9001idckr-in-sc70-5-packageTue, 26 May 2026 18:53:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:5dbfb2cc-f4bd-4ee6-8b75-0cfb69e4ab04Michael GendelsmanPart Number: TLV9001 I need pinout of TLV9001IDCKR in SC70-5 package.TLV9001https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1649566/tas2505evm-noise-on-tas2505evm-board-at-16khz-wclk-and-external-masterTue, 26 May 2026 18:39:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:a026914c-8486-4955-b680-3297eda89b67Danilo A.Part Number: TAS2505EVM Other Parts Discussed in Thread: TAS2505 Hi Team, Posting on behalf of our customer. I'll share this E2E post with our customer so he can reply when needed. I am currently working on I2S communication between an EFR32 device and the TAS2505 EVM board, and I encountered an issue when using a 16kHz sample rate. As I understand, WCLK should be equal to the sample rate. In my case: WCLK = 16kHz Word length = 16 bits Stereo audio Therefore BCLK = 512kHz The issue is that the audio output from the TAS2505 speaker contains noticeable noise/distortion (“buzzing” or “crackling”) when operating at 16kHz. However, when I increase the sample rate to 44.1kHz or 48kHz, the audio becomes much cleaner, which seems expected. What is strange is that with exactly the same firmware, same audio data, and same 16kHz configuration, another DAC/amplifier (MAX98357A) produces very clean and clear audio output. So I would like to confirm a few things: Could this issue be related to differences in the hardware architecture/design between TAS2505 and MAX98357A? Is it expected that the TAS2505 EVM board may produce more audible noise or degraded audio quality when operating at 16kHz sample rate? The TAS2505 EVM board includes the TAS1020B onboard USB interface, which seems to run with a default 48kHz audio configuration. Is there any application, firmware tool, or method available to modify the TAS1020B firmware/configuration so that the board can operate with 16kHz WCLK instead of the default 48kHz? I would like to test whether the issue is related to clock synchronization or USB audio configuration. Additional information: I configure the TAS2505 EVM through the CodecControl application. My configuration script is similar to the Class-D example script. I only changed the divider settings: NDAC = 1, MDAC = 6 or NDAC = 2, MDAC = 3 Regards, DaniloTAS2505Home theater & entertainmentTAS2505EVMhttps://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1649313/ina849-analog-potentiometer-to-control-gain/6359204Tue, 26 May 2026 18:30:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:670692af-c672-4483-ac18-a18ed0b9c3d2Robert Clifton56Hi Alvaro, I have a few questions. Is a manual (where someone manually adjusts it) potentiometer acceptable? Was there a reason that you wanted to use a potentiometer rather than using a programmable gain amplifier? Best Regards, Robert Cliftonhttps://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1648458/tlv9022l-tlv9022l-pspice-lib-file-simulation-error/6359142Tue, 26 May 2026 17:47:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:4e1d9ea4-d30c-4b4b-971a-5d7e7f98efd4Marek Lisdonehttps://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1648830/lm111-date-code-decode/6359124Tue, 26 May 2026 17:41:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:a3af2f38-f732-4284-9de2-48f3402e74d4Paul GroheRon, MD8 is Military (883) bare die. In our systems it would be looked-up as LM111-MD8 (dash instead of space). Karthik, 42AHS91 This is a valid lot from Feb 24th 20204 from the Philippines test site. The "42" is the last digit of the year (4) and the month (2=Feb). AHS9 is an internal lot trace code and has no meanings outside of TI. Nothing to "decode". The "1" is the assembly site code (1 = Clark A/T). The die is the ex-National Semiconductor die.https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1649494/tlv3901-question-regarding-tlv3901-latch-functionality-and-tina-model-behavior/6359111Tue, 26 May 2026 17:33:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:75558223-5f88-4b03-9a62-7f1fa533f4e7HO SIUHi Hadi, You are correct. There is currently an error in the model where the internal 50Ω pull up to VCCO are not implemented. This will be fixed in the next iteration of the model. For the resistor to GND on the LE pin, it depends on your VCCO. If you're using a 3.3V VCCO, the 500Ω resistor should apply a -300mV differential between LE and LEB so this should be valid configuration.https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1648642/tlv3901-clarification-request-on-tlv3901-cml-output-termination-requirements/6359094Tue, 26 May 2026 17:20:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:a5ce452b-1408-438d-a5ae-d35edd7d400cPaul GroheHello Hadi, 1. Yes. There are internal 50 ohm resistors to VCCO inside the TLV3901. These provide the reverse termination for the output. 2. There should be a 50 ohm resistor at each of the inputs *AT* the receiver (FPGA) to the VCCO voltage. See the following application reports on terminations and AC coupling for more information: AC Coupling Between Differential LVPECL, LVDS, HSTL and CML (Rev. C) DC-Coupling Between Differential LVPECL, LVDS, HSTL, and CML Interfacing Between LVPECL, VML, CML and LVDS Levels Comparator Output Types (see section 2.3.4)https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1649306/opa4323-power-rail-is-asymmetrical-when-using-lm7705/6359093Tue, 26 May 2026 17:20:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:68d5cd2c-3e89-48af-9d41-e8b7b2d23e2aRon MichallickHello DH, LM7705 clock is 92kHz. I expect some harmonics of that clock will also be in V- supply. What is the bandwidth of these high gain amplifier circuits? Obviously keep that well below 92kHz. Chart is PSRR for negative supply.https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1649537/tlv3605-tlv3605-output-asymmetryTue, 26 May 2026 17:17:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:e3a746ff-6f64-4c08-8a84-0bfde5f3fdc7Charles GordonPart Number: TLV3605 Hello, I'm using the TLV3605 in an optical receiver, and am seeing asymmetry in the lvds output. In my design, the TLV3605 is driving an FPGA input, connected by a 100 ohm differential coplanar waveguide with 100 ohms receiver termination. I'm probing directly at the output of the comparator w/ a differential probe. The comparator's 3.3V supply is decoupled similarly to the evaluation board (TLV3605EVM), and the hysteresis is set close to the minimum ~10mV. You can see the asymmetry in the picture below, where the differential output settles to ~275mV on one side, but only ~200mV on the other side. Could you please advise on possible causes of this?TLV3605TLV3605EVMWireless Infrastructurehttps://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1648959/opa4376-q1-amplifier-output-with-high-offset/6359076Tue, 26 May 2026 17:05:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:0bd0cc6a-b2dd-4623-8642-908431406872Ron MichallickHello Tony, [quote userid="577054" url="~/support/amplifiers-group/amplifiers/f/amplifiers-forum/1648959/opa4376-q1-amplifier-output-with-high-offset"] measured REF35125 output 1V25 = 1.249V and 500mVin = 0.515V as expected,[/quote] This is not expected for me. With no load of 0.5V, it should be nominally 499.6mV; 515mV is 3.1% high. This error should be understood first. 1.7V is 11% high. Are you certain that all the ground points in this circuit are 0mV? Pick a common ground point then measure the ground side of each resistor that connects to ground. Also check to see if any output oscillates. I do not see the loads, are they capacitive? There are also no capacitors on the feedback resistors, this can erode some phase margin.https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1649117/usb2any-the-usb2any-can-t-detect-bq25798-battery-charger/6359073Tue, 26 May 2026 17:02:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:1724aaf3-d101-44e3-8e6e-53ca43e7ed92Jeff FHI Joshua, You may need to update the USB2ANY firmware. Regards, Jeffhttps://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1648830/lm111-date-code-decode/6359040Tue, 26 May 2026 16:42:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:a0672c44-92c6-4e88-81ce-29aba61a21c8Ron MichallickHello Karthir, LM111 MD8 is not a valid part number. Is it one of these?https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1644428/ina240-ina240-current-sensing-design/6359026Tue, 26 May 2026 16:36:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:05016381-84db-4762-8c8a-d3c9a7e22bc9Levi DVHi Luca, The REF1 and REF2 pins are both part of a voltage divider that will average the zero current output voltage, so they are often shorted to the VS pin and GND pin of the INA240 itself for bidirectional operation: If you want to use an external reference to set the reference output to midsupply I would recommend shorting the ref pins to each other and connecting them to the reference voltage. For the REF2033, the VBIAS pin is the correct output since it will output a voltage that is half the supply voltage. I wouldn't recommend connecting the VREF pin to the 3.3V supply however, since that supply is already driven by another source. Let me know if you have any more questions, Levi DVhttps://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1649486/ina333-sawtooth-waveform/6359014Tue, 26 May 2026 16:29:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:b019475a-4dfa-43c5-bbd4-98c8ebb16fa1Taylor AllanHi Marvin, I would first check what the inputs of the INA look like to see if they are DC voltages. Also, is the node circled below a correct connection point? One thing that I do notice about this schematic is that the reference is not buffered. If the REF pin of an INA sees a large input impedance, the CMRR of the device can degrade significantly as explained in this section of the datasheet. If there is significant ripple on any of the voltages sources above, you can see ripple on the output, especially VG1 due to CMRR degradation. Could you measure if there is any ripple seen on any voltage sources? Also, if you create a low impedance connection on the REF pin to GND, does the issue persist? Best Regards, Taylor Allanhttps://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1649523/lmh32404-technical-support-request-output-oscillation-in-lmh32404yr-based-apd-tia-circuitTue, 26 May 2026 16:28:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:8d793535-4f7a-4fab-b04c-a250cca2e35fJong-sik ShinPart Number: LMH32404 Hello, I am designing a TIA circuit using the LMH32404YR to amplify signals from an Avalanche Photodiode (APD). I am currently encountering an unexpected oscillation issue at the output, and I would appreciate your technical guidance to resolve it. 1. Circuit Configuration TIA: LMH32404YR (4-Channel High-Speed TIA). Input Stage: APD cathode is directly connected to the TIA input pins (IN1–IN4). Bias: APD anode is connected to the high-voltage bias (APD_HV_N). The bias line includes an RC filter (10k ohm + 10nF/100pF). Output Stage: The outputs (AMP_P/N) are connected to an FPGA LVDS input port, and a 100-ohm termination resistor is applied at the FPGA end. 2. Problem Description I am observing high-frequency oscillation at the output (AMP_P/N) even when no input signal is present. The oscillation persists despite keeping the input traces as short as possible in the PCB layout. 3. Questions Input Stability: How does the junction capacitance of the APD, when directly connected to the LMH32404 input, affect the stability of the TIA’s feedback loop? Termination Impact: Does the 100-ohm termination at the FPGA LVDS input interact with the LMH32404 output stage in a way that could induce instability, and is there a specific output matching requirement? Layout and Filtering: Could you recommend PCB layout best practices (specifically for the input traces and grounding) or modifications to the bias filtering to suppress this oscillation? Stability Optimization: Are there any recommended damping components or register/configuration settings for the LMH32404 to ensure stability when driving an FPGA LVDS interface with direct-coupled APD inputs? I have attached the schematic for your reference. Any advice on debugging this oscillation or optimizing the circuit for a stable interface with the FPGA would be greatly appreciated. Thank you for your time and assistance. Best regards,LMH32404Aerospace & Defensehttps://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1649117/usb2any-the-usb2any-can-t-detect-bq25798-battery-charger/6358916Tue, 26 May 2026 15:48:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:822f5c7c-c3e5-43e0-99ca-5ca277d83c27Joshua SalinasHello Rajesh, I will transfer your E2E post to the team responsible for BQ25798. Thanks! Regards, Joshhttps://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1649494/tlv3901-question-regarding-tlv3901-latch-functionality-and-tina-model-behaviorTue, 26 May 2026 15:32:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:d976c435-3898-4b6c-ab0d-2beda2360c02Hadi AzarPart Number: TLV3901 Question Regarding TLV3901 Latch Functionality and TINA Model Behavior.docxTLV3901Data center & enterprise computinghttps://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1649486/ina333-sawtooth-waveformTue, 26 May 2026 15:25:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:08a60e51-46ff-4cb2-96ba-195b752f9ea7Marvn ArcangelPart Number: INA333 Hi experts, Need advice on this one. The simulation shows straight line but when the circuit was built, the output showed a sawtooth waveform instead. What could be the issue? More information: 1. The oscilloscope probe I used is standard lenght. 2. There are no long wires between the output point and the measurement terminal; the oscilloscope probe is connected to the output point via a 5 cm wire. Regards, MarvinINA333Test & Measurementhttps://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1648189/ths3491-output-can-not-reach-5-5v-beyond-300mhz/6358852Tue, 26 May 2026 15:17:00 GMTcb01d8b2-d089-468d-babb-77d1d8683490:e0894662-737c-407e-9701-607ea2307275Ignacio Vazquez Lam1Hi, Can you confirm if this measurement is being done without any sort of load at the output. We get around ~500MHz of bandwidth at 5Vpp with this device in a similar supply configuration as the one you mentioned. I am wondering if maybe loading is affecting the measurement. If you probe at the input of the device where the 50ohm termination resistor is placed. Is your input signal the same amplitude up to the frequencies of interest? Best Regards, Ignacio