Q&A - Recent Threads

Reference Design

BMM — Mon, 10 Aug 2026 05:26:00 GMT

Hi Team,

Am designing the LT7184S IC for 3phase, 4 phase and 6 phase requirements. Is there any reference design multiphase? or any design checklist.

Thanks,

Regards

lot number traceability

Xaniex — Mon, 10 Aug 2026 01:57:16 GMT

Good day,

I have this component devices ADI LT8391DJUFDM#WTRPBF with a lot number BC51036.5 and a date code of 2602 which cannot be trace.

May I ask if this lot has a histroy record in your system.

Best regards,

Joxan

Current Ceiling for LT3763

RJPower — Sun, 09 Aug 2026 17:21:12 GMT

Hi,

I designed a 20A LED strobe light with the LT3763. Now I need to raise the pulsed output current up to 30A. I know the 3763 promises only up to 20A, but I was wondering if there was any reason besides low signal amplitude that would prevent me from going to 30A with this driver. I am very space constrained and I need a wide input of 9 - 56V. If I could just swap out my power stage components and current sense resistor that would be my ideal solution.

Thanks,

Piezoelectric energy

Roman01 — Sat, 08 Aug 2026 15:39:53 GMT

Hello, im trying to do a project about piezoelectric energy, the point of the project is to demonstrate if we can use the piezoelectric energy generated with piezoelectric plates situated inside of a shoe. The issue consist in how to correctly connect all the ports of the LTC3588 chip and later how to connect the LTC3588 to the TP4056? Im connecting the LTC3588 to the TP4056 because i already got a working circuit that consists of the TP4056, a module booster MT3608 and a LiPo batery of 3.7V and 1100 mAh. In the photos you can see: Photo 1: LTC3588, Photo 2: TP4056, Photo 3: Alternative version of LTC3588 in another circuit (which also contains ports like Pgood, CAP, Vin2, SW). The Photo 3 chip is moslty shown in videos or explanations, but less viewed in internet shops. Would be very grateful if you could help me, there may be errors or the circuit may be not even possible, sinse i am a novice in this field.

Thanks soo much.

ADALP2000 - LTM8067 Breakout Board

UnstableMolEE — Sat, 08 Aug 2026 02:50:42 GMT

Hello,

I have the ADALP2000 kit and want to check the LTM8067 against the datasheet. Unfortunately I can not find a schematic online of this breakout board. It seems pretty straight forward. Just a 10k potentiometer, ltm8067, a few resistors, and a few caps.

Thank you for the help.

Pass-Through-Like Operation of the MAX25201

KOAtrel — Fri, 07 Aug 2026 07:55:40 GMT

I have a question regarding the use of the MAX25201.
I am considering using this IC in an application where the input voltage condition is:
Vin(min) =< Vout_target =< Vin(max)
and the requirement is that the output voltage must not drop below Vout_target.
In other words, it is acceptable for the output voltage to remain anywhere between Vout_target and Vin(max)+α.

I understand that a pass-through capable device, for example MAX25203, would normally be used in this type of application.
However, I would like to know whether using the MAX25201 in this manner would be appropriate.
When Vin is higher than Vout_target, I expect that the switching activity will be minimized because the IC would operate in skip mode.
In this case, the switching should occur only as needed to maintain the bootstrap voltage, resulting in little or no effective boost action.
Could you please comment on whether this usage is acceptable and whether my understanding is correct?

Part Marking Verification

Quad_X_ — Thu, 06 Aug 2026 21:00:30 GMT

Hello,

I palce both LTM4634IY#PBF and LTM4634EY#PBF on various printe cuircuit boards - how ever I mixed them up and I need to sort them.

The white paper states "e1" is the marking for both part numbers - there any other way to verify the part is correct?

Thanks for direction.

Eric

Threshold Variation in LTC4368 – Calculated UV/OV Thresholds (7 V / 36 V) vs Measured Hardware Thresholds (2 V / 53 V)

SystemControls — Thu, 06 Aug 2026 10:35:55 GMT

We are evaluating the LTC4368HDD-2 in a 24 V protection circuit designed according to the LTC4368 datasheet.

The UV and OV resistor network was calculated using the equations provided in the datasheet with the following resistor values:

R1 = 3.9 MΩ
R2 = 243 kΩ
R3 = 59 kΩ

The intended protection thresholds are:

Undervoltage (UV): 7 V
Overvoltage (OV): 36 V

These values were also verified through simulation, which produced the expected operating range of 7 V to 36 V.

Measured Observations

At VIN = 53 V, the OV pin measures approximately 0.49 V, and the LTC4368 immediately turns OFF the external MOSFETs.
During UV testing, the output turns OFF at approximately 2 V input. At the instant of UV shutdown, the UV/SHDN pin measures approximately 0.7 V.

LTC4367 - Method of protecting VOUT pin from reverse voltage

aisnok — Thu, 06 Aug 2026 07:53:04 GMT

Hi ADI experts,

I am designing a circuit using the LTC4367 and would like to protect the VOUT pin from reverse voltage by adding a resistor, based on Note 3 on page 4 of the datasheet.

Note 3 states: "These pins (UV, OV, SHDN, Vout) have a diode to GND. They may go below –0.3V if the current magnitude is limited to less than 1mA."

Could you please help me with the following questions?

1.
Will adding a resistor have any adverse effect on the normal operation of the LTC4367?

2.
During MOSFET gate charging or discharging, is it possible for the current flowing into or out of the VOUT pin to exceed the value of I_VOUT specified in the Electrical Characteristics table of the datasheet?

3.
Could you provide the forward voltage versus forward current characteristics of the internal protection diode connected to the VOUT pin, particularly for currents of 1 mA or less, including the temperature characteristics?
I need this information to calculate the worst-case current at the VOUT pin.
If the characteristics of the internal protection diode cannot be provided, could you please advise us on how to design the circuit so that the current at the VOUT pin remains below 1 mA under all operating conditions?

thanks

Inverting Application

PhilipL — Thu, 06 Aug 2026 03:52:56 GMT

Hi,

Is LT3840 applicable to inverting output voltage? From the LTSpice, I follow the circuit design from the datasheet which I couldn't get the output voltage and current output rating as stated.

My parameters are:

1. VIN is 24V

2. VOUT can be adjustable from -9V to -17V

3. Output current rating should be at least 20A and above, able to achieve?

LT8304 Load Regulation problem

priyanshi — Wed, 05 Aug 2026 18:31:17 GMT

The LT8304 IC is not functioning as expected. Load regulation is not occurring, and the output voltage is significantly lower than the expected value. The schematic is attached for reference. Could you please review it and help identify the possible cause of the issue?

please help.

Extremely low efficiency of the LTC3108

NicolasBustamante — Tue, 04 Aug 2026 23:52:49 GMT

When using an LTC3108 for energy harvesting from a TEG with a 1:100 ratio transformer, the voltage measured at the TEG outputs is 37 mV already connected; the capacitor connected to the Vout pin is 50 mF (with very low losses and low ESR), and pins VS1 and VS2 are configured to obtain 4.1 V at Vout.
The generated current is less than 0.2 µA, meaning the system efficiency is far lower than specified in the datasheet (up to 38%)
Is the problem due to the value of the output capacitor (Cout)? Is it possible? Or where might the problem be coming from?

LTC3260 unused LDO-

jwright — Tue, 04 Aug 2026 15:49:38 GMT

Hi - what is the recommended connection if the inverting VOUT is used but LDO- is not? Can LDO-, ADJ-, BYP- all be left floating?

LT8361 Output Voltage Stuck at 13V

kuremiya — Tue, 04 Aug 2026 06:49:51 GMT

I am using the LT8361 as a boost converter.

Unfortunately, I cannot share the schematic due to company confidentiality.

VIN = 10 V

The output voltage only rises to approximately 13 V, while I expect a much higher output voltage based on the feedback resistor values:

RTOP = 1 MΩ

RBOTTOM = 20 kΩ

I verified that the output diode orientation is correct.

One concern is that there was a PCB routing mistake involving pins 9 and 12. To correct it, I bent the pin and added an external bypass wire.

Could this modification cause the converter to stop regulating properly?

Are there any common failure modes or measurements you would recommend checking first?

Thank you.

No load input current is larger than expectation

Runtime — Tue, 04 Aug 2026 02:56:09 GMT

Hi,

I am using the DC2841A EVM board to evaluate the LT8648S. By changing the resistance around FB pin, I modified the output voltage to 15V.

However, I encountered a strange issue. When the EVM board is supplied with a 24V input voltage and the output is no-load, the input current reaches as high as 150mA when operating in Spread Spectrum mode. However, when Burst Mode is enabled, the no load input current drops to less than 1mA.

This difference seems unusually large. Could you pls advise whether the behavior is expected, or if these are any known causes that should be investigated?

Thank you for your support.

LT8638S Power-Up Sequence (EN Before VIN)

Tommybanco — Mon, 03 Aug 2026 14:26:56 GMT

Hello,

I have a question regarding the LT8638S power-up sequence.

Is it supported to drive the EN pin high before VIN is applied?

In my setup, VIN and EN are supplied by two independent 5 V power supplies. I observed the following behavior:

If VIN is applied first and EN is asserted afterwards, the device starts normally.
If EN is driven to 5 V first and VIN is applied afterwards, the VIN power supply immediately enters current limit and its output voltage collapses.

The converter is unloaded during this test.

Is this operating sequence supported, or does the LT8638S require VIN to be present before EN is asserted?

Thank you.

I'm looking for gerber files of the LTM4732 EVB

AD9084 — Sun, 02 Aug 2026 08:23:09 GMT

I'm looking for gerber files of the LTM4732 EVB

Configuration When the Battery Voltage and AC Supply's Voltage are Almost Equal

jimolson52 — Sat, 01 Aug 2026 20:09:11 GMT

Below is a circuit I drew recently describing a circuit to power an embedded computer system from either:

(1) an open frame 12VDC line-operated power supply
or
(2) a 12VDC sealed lead acid battery.

The embedded computer is powered from the power rail identified below as VSYS.

My schematic was drawn using as a guide Figure 2 in LTC4416's datasheet, which might be my problem.

My desired control strategy is quite simple: power the embedded computer off the 12V line-operated AC power supply until it disappears in a storm-induced outage of AC power, then power the computer from the 12V SLA battery until AC power gets restored. I want to avail myself of the LTC4416's ideal diode behavior in all power transfers because the load current is several amps.

The challenge here (if there is any. Maybe I'm overly cautious.) is that 99% of the time my two DC power sources have approximately the same voltages. Thus the two circuit examples offered up in LTC4416's data sheet (Figure 2: Vbat>Vac and Figure 3: Vbat<Vac) are not exactly pertinent to my situation.

I cannot cope with any power transfer behavior that acts upon which of the two power sources has the greater voltage. When AC power returns from storm outage the VSYS load should be powered from the line-operated power supply, not the SLA battery simply because its voltage is greater.

The circuit I drew above seems to protect a partially-drained battery from being charged by the AC power supply by blocking action of the upper left MOSFET--which is highly-desired behavior. I do not want the AC-powered side to attempt to charge the battery.

But there is no back-to-back MOSFET pair associated with the V1 (AC Power) side, so nothing prevents the battery-powered VSYS rail from back-pumping current into the AC power supply through its constantly-enabled right-most MOSFET. I have no idea how the open frame AC power supply reacts to current being injected into its output, especially when the driving source will try to pull the AC supply's output port to voltage greater than its regulated set point.

Is the fix to equip the AC power side of my circuit with a second PMOSFET, making the AC side a full back-to-back PMOS transistor pair like the battery side?

Thanks for any input you might offer on these challenges.

Regards from still steamy Indianapolis in the summer.

Start-up/Regulation issue in No load and light Load Condition

DP25 — Sat, 01 Aug 2026 12:59:39 GMT

A 48‑Watt power supply was developed using the LT3798. The design references the evaluation board DC1817B, with additional modifications shown in the attached image. A custom transformer of 300 µH is used in this design.

The issues observed are as follows:

At an input voltage of 80–115 VAC under no‑load conditions, the output is unstable and does not regulate properly. It dips to 22 V and rises to 28 V.
The output capacitance is 3000 µF (3 × 1000 µF) with a load resistance of 1.02 kΩ. Only when a additional load of 160 mA is applied the output regulates to 24 V and become stable.

Two compensation combinations were tested:

DC1817B reference values: R37 = 0 Ω and C7 = 2.2 µF
Modified values: R37 = 1 kΩ and C7 = 1 µF

With both combinations, the issue remained unresolved.

Stabilizing the regulation loop

WNM — Fri, 31 Jul 2026 22:43:26 GMT

Regarding the selection of the value of Rc connected to the "Vc" pin, the datasheet says the following:

When using an output capacitor Cout larger than 10uF, as is needed for large PWM dimming ratios, a resistor Rc in
series with Cc is also necessary. Larger values of COUT require larger values of RC. See Typical Applications for
some examples.

Looking at the "Typical Applications", it is hard to make out any definitive pattern.

Cout = 4.7uF uses Rc = 0 & Cc = 0.01uF - LED Driver with Duty Cycle LED Current
Cout = 20uF uses Rc = 20k & Cc = 0.01uF - 24V Voltage Regulator with Spread Spectrum
Cout = 10uF uses Rc = 16k & Cc = 0.0001uF - EMI performance
Cout = 22uF uses Rc = 162k & Cc = 0.01uF - 2A LED Driver with Internal PWM Dimming
Cout = 4.7uF uses Rc = 517k (or 30k) & Cc = 0.00047uF - Multiple String Drivers from Single Boosted 56V Input

Some small values of Vout use very large values for Rc while others do not. A 20uF (2 x 10) Vout uses Rc of 20k while a 22uF Vout makes a big jump to 162k.

Isn't there some calculation available to better define what value actually should be used or is this a matter of leaving space on the board for the component and figuring out something that works after it is all assembled?

Does any of this change if analog dimming is being used rather than PWM dimming?

LTM8003 questions

bharti8 — Fri, 31 Jul 2026 16:56:31 GMT

I have a few questions about implementing LTM8003 in a design.

Is this part automotive qualified?
Can I output 3A at 15V?

My design requirements are Vin=24-36V, Vout=15V, Iout=3A MAX.

About the right MOSFETs with the LTC7803 at Vout=3.3V and Iout=10A

Leonardo2020 — Fri, 31 Jul 2026 14:25:16 GMT

Hello Everyone,

I hope you can provide me your opinion about my choice for the MOSFETs to use with thew LTC7803.

My main specs are:

Vin = 12V

Vout = 3.3V

Iout = 10A

fsw = in the range 100-300 kHz

Tamb <= 50 °C

I choose Infineon IQDH35N03LM5CGSC because of its very low Rdson (<0.4 mohm with Vgs = 4.5V and Id = 50 A), good thermal resistance (about 0.5 °C/W junction/case and 50 °C/W junction/ambient) and possibility to have double side cooling, very useful considering the high Tamb. My goal is to maintain the DCDC circuit as cool as possible.

This MOSFET is also logic level, that is necessary considering that the LTC7803 can drive it up at 5V. Only its Qc (about 90 nC) is not low.

I would like to have your opinion on my choice.

Thank you very much in advance.

ez.analog.com/.../Infineon_5F00_09_2D00_04_2D00_2024_5F00_DS_5F00_IQDH35N03LM5CGSC_5F00_2_5F00_0.pdf

LT80603A start with a connected load

OlekTg0 — Thu, 30 Jul 2026 12:28:33 GMT

Dear ADI team,

We are currently considering LT80603A chip for use in our design.

Tell me, please.

If input voltage is 7..15 V and output voltage is 5 V.
Can the chip start with a connected load close to the maximum?
E.g., a 1.2 Ohm resistive load is connected to the DC/DC-board output, and then we apply input voltage to the board.

Did AD do such tests?

I ask because we have already struggled with chip from other manufacturer, which has a declared wide range of input voltages from 3 to 65 V, but in fact starts normally only when the input is 24 V or more:) With 12 V input, it outputs only a saw with 1-2 V amplitude until the load is removed.

And we are now selecting DC/DC-controller that can operate stably in the input range of 7..60 V with an output of 5 V.

Reg: LTM8027 for 24V TO 12V

SJS — Thu, 30 Jul 2026 08:25:28 GMT

Hi Team

LTM8027EY#PBF for 24V to 12V /3A conversion and i created below circuit. is it correct. pls check
Am using

Query on LT3083 Zero-Volt Output Behavior and Alternate Regulator Recommendation

EngineeringChad — Thu, 30 Jul 2026 07:23:51 GMT

Hi Team, I am using the LT3083IDF#PBF with a 3.3V input supply and an externally controlled DAC in place of the conventional RSET resistor to program the output voltage. Since the LT3083 utilizes an internal voltage follower architecture,
I expected the output voltage to track the DAC setting and remain near 0V when the DAC output is set to 0V.

However, the measured output voltage under load is as follows:

Load Resistance	Output Voltage
900 Ω	0.32 V
450 Ω	0.287 V
100 Ω	0.03 V

Could you please advise whether this is expected behavior and explain the root cause of the residual output voltage?

Separately, I am seeking an alternative regulator with the following capabilities:
Input voltage: 3.3V Adjustable output voltage: 1.7V to 1.9V
Remote sense feedback pin Programmable output voltage suitable for board bring-up and testing applications
I have reviewed the ADP1765; however, its operating/input voltage limitations do not appear to support my use case.

Could you recommend any suitable Analog Devices solutions?

Best Regards,
Sunil Shailon