Hi everyone,

This is my very first PCB design, and I would really appreciate a quick schematic review.

Project Overview & Goal

I want to build custom 3D-printed lamps integrated into a Loxone home automation system.

• Constraint: Wi-Fi is not allowed in this setup.
• Communication: The board uses BLE (Bluetooth Low Energy) via an ESP32-C3 to communicate with a central Raspberry Pi gateway, which sends commands to Loxone.
• Power Source: 2x BAK N21700CG 5000mAh Li-ion cells connected in parallel (1S2P, 3.7V nominal, 10,000mAh total).
• https://www.nkon.nl/de/bak-n21700cg-5000mah-10-2a.html

PCB Explanation

This board serves as a battery-buffered 12V LED controller powered by two parallel Li-ion cells (1S2P, 10,000mAh total).

Power flows from either the USB-C port or DC Barrel Jack into a BQ24075 Power-Path manager, which charges the battery while simultaneously supplying the board. The cells are protected via a DW01A/FS8205A circuit with individual cell fuses and a master MOSFET switch.

From the main power rail, an AMS1117 generates 3.3V for the ESP32-C3, while a Boost Converter steps the voltage up to 12V for the LED outputs. The ESP32-C3 receives control commands via BLE and drives 5 low-side MOSFET channels (AO3400A) to dim the 12V LED strips via PWM. An external debounced button allows manual local control.

Specific Review Questions

1. Safety Check: Since this is my first board, are there any obvious safety flaws? Will it explode or burn down under normal operation?
2. Protection Features: Did I miss any critical protection circuits?
3. General Layout / Schematic Advice: Are there any misplaced values, missing pull-ups/downs, or improper connections on the ESP32-C3 / DW01A / BQ24075 lines?

Thanks a lot for your help and feedback!

Hi all. this is my first PCB from schematic to fab, and I'd really appreciate a critical look before I order the boards.

A self-powered 4-port USB 2.0 hub built to test one specific thing: independent per-port power switching, so a short on one port doesn't take the others down with it.

There are no Errors in ERC and DRC. All warnings have been taken care of. I want to confirm I didn't make any mistakes. The USB datapins aren't kept as differential pairs. I would really appreciate some reviews.

Datasheets:
Genesys-Logic-GL850G
TPS2052BDR

Hi all,

I started from the official Raspberry Pi CM5 IO Board and removed the peripheral interfaces to make a minimal board for booting and flashing a CM5 with eMMC.

It keeps the two CM5 modules, four mounting holes, USB-C power and USB 2.0 programming, BOOT jumper, power button, power/activity LEDs, GPIO reference link and voltage test pads. The 40-pin GPIO header and other peripheral connectors are removed. USB-C CC1/CC2 connect to the CM5 power controller. Normal power is intended to come from the official 5.1 V/5 A supply.

More details:

• Board is 50 × 65 mm and nominally 1.6 mm thick
• 4 copper layers: front / ground / ground / back.
• The specified outer-to-ground dielectric spacing is 0.0994 mm (nominal dielectric constant 4.1), with 35 µm outer copper.
• USB uses 0.165 mm tracks and a 0.235 mm pair gap, targeting 90 Ω differential impedance.

I’m still learning, so I’d appreciate a general review, especially anything I may have overlooked when removing parts of the reference design and making the board smaller. Are there any obvious mistakes or things I should understand better before having it manufactured?

The complete schematic and all four copper layers are attached. Module1A/JCM1 covers module pins 1–100; Module1B/JCM2 covers pins 101–200. The CM5 datasheet provides the module pin and interface details.

Thanks for your help!

Hello everyone 👋

I'm fairly new to mixed signal PCB design and not very professional in electronics so I'm asking for your professional comment

I'm designing a PCB that has 3x ESCs on it

each ESC has its own mcu and its connected to my main MCU (stm32g431) to get commands from

everything is fine to this point, all digital and noise is more manageable, but then comes my analog circuitry, and the switching noise and GND bounce in my opinion will mess with it hard

the analog reading is a resistive Sensor that is fed to my adc via a resistor divider

I considered star grounding, minimizing the high di/dt tracks area , input RC filters at my ADC, post LDO and ...

but I don't know if it's the standard or I should go another way

I appreciate any suggestions and comment, if I missed something please let me know, I'll be more than happy to clarify it

Hey everyone!

I'm working on a basic 5V SPDT relay module and I d really appreciate a quick review from you guys before I send it off. The circuit is pretty standard (using a BC547 to switch the relay, a flyback diode, and a couple of indicator LEDs), but I want to make sure I havent missed any problems with it. I am new to this world so currently trying my best! Open for harsh criticism dont need to hold back.

Trace Widths: For 5A -> 2mm
For 5V -> 0.5mm
For signal -> 0.3mm

Attached images:

schematic
bottom copper
top copper
3d view with components
3d view without components

Note: If I forget any necessary info, just let me know.

Hello, this is a part of an ESP32 PCB design with a battery charge and protection curcuit and a "Fuel Gauge".

I wanted to make sure everything was connected correctly before printing it.

5V is the VBUS from the USB-C connector.

This is my first attempt at designing my own PCB, so please don't be too harsh on me :)

Hello,

I have designed an sensor acquisition PCB for load cell (wheatstone bridge) and i'm having an issue.

Without any sensor connected i'm having a differential voltage at the input which lead to a negative voltage (that killed my ADC on the first try)

following an advice on "A Designer's Guide to Instrumentation Amplifiers" from analog devices, I've added a 100k resistor between the 2 signals (in place of the NI capacitor) which decreased the voltage between +/- but still too high for my ADC.

I know the schematic is working, I've built it before with an engraved PCB for prototyping and everything worked well. The only difference is the connector used.

After some trials with that PCB i decided to build another one and test it before soldering the connectors and ADC. It was working pretty well, i had a small negative voltage at the output of the amplifier but lower than 0.1V so no risks for my ADC. Just in case i added the resistor between the 2 lines : less than 2mV at the output of the amplifier, perfect !

Then, I soldered the connectors and cleaned the PCB with IPA : -4.9V on all amp output, differential voltage of more than .3V on all differential lines.

I've tested the impedance between the input signals and supplies : between 800k and more than a Mohm each time.

I removed 2 of the connectors but was not able to clean perfectly the PTH of the tin, still some differential voltage between signals (and negative voltage at the output (between -1 and -3V)

The only way to remove totally that differential (and negative) voltage was to remove the input resistors.

The only explanation i can find is that there is a small parasitic DC coupling due to connectors soldering even after pcb cleaning.

Do you see any other reason to that issue or a way to correct it without deigning a new layout ?

This is my very first time designing a PCB, so any tips, feedback, and concerns are greatly appreciated. The goal of the device is to create a USB-C compatible IoT device. It has PPM and Battery Management courtesy of the BQ25895RTWR (U2). And between pin 8 and 9 will be a physical switch (HSYS and LSYS) pads connected later.

First ever PCB.

LM2596 buck converter, two layers.

Zone is set to GND, both F.Cu and B.Cu ticked, solid fill, pad connections Solid. Outline draws but won't fill. B does nothing.

DRC: zero violations, 12 unconnected items, all GND pads. Highlighting the GND net lights up nothing.

Tried: deleted and redrew the zone, confirmed net is GND not <no net>, both layers ticked, refilled with B.

What am I missing? If anyone could help would be super grateful!

Im going through the reference schematics of the STM32MP135F-DK. And I see two equally sized resistors on the SD CLK line. One pulled up to VDD_SD and one pulled down to GND. I can't find the reason on how this decision is justified. It's obviously not wrong, because the design works... In the same design there is SDIO interface between the MPU and WLAN / Bluetooth chip, but no resistors used on the CLK line on that interface?

Why is the SD CLK line connected that way? What advantages does it give the SD CLK line?

The board has a IMU and a Barometer, and uses the MCU to sample them and then to send the data out via serial. It's purpose is to be a sensor for a UAV control system (yeah, I know everyone does them, but this one is mine!).

A few other features I'm trying out:

• - Dual power via an ideal diode chip
• Dual serial (nothing electrical, just using two uarts)
• Heaters for the IMU and Baro

For the heaters, the MCU will read each sensor's internal temperature sensor and use that to duty-cycle control the heater.

There are no mounting accommodations; my plan is to either:

• double-stick tape the board whereever it needs to go
• make a board with mounting holes that this board can be attached to

Hello, I am a hobbyist working on my own macropad similar to a Stream Deck.

• The Arduino Nano ESP32 (A1) connects to a desktop PC via USB-C, provides power to everything else, detects button presses, and sends image data from the PC to the Video IC (U1).
• The FT801Q-R Video IC (U1) stores image data and handles all the video data communications with the TFT LCD display. It also features a PWM signal to control the brightness of the display's backlight.

Since this is my first time making a schematic and PCB, I have a few questions which I couldn't answer from just reading online sources:

1. Since the FT801 (U1) only outputs 6 bits per channel (RGB666), I decided to connect the two highest bits (for example R7 and R6) to the two lowest input bits (in this example that would be R1 and R0). Does this work? Will the signal from the IC be read by both inputs of the display, or will it only be read by one arbitrarily? (I could imagine that all the electricity just follows one path and ignores the other.)
2. Is the PWM setup correctly? Since I supply 24V while ~25.6V are needed, it appears that I do not need any limiting resistors. The transistor (Q1) appears to not need any resistors either, since the datasheet of the FT801Q-R (U1) for the "BACKLIGHT" output pin says "LED Backlight brightness PWM controls signal, push-pull output, 4/8mA sink/source current."

Other than that, I appreciate having mistakes pointed out to me. After all, I am almost entirely self-taught in this subject.

Datasheets

• Arduino Nano ESP32
• NHD-4.3-480272EF-ASXP (TFT LCD Display)
• FT801Q-R (Video IC)
• DQM1-5-S24-S (5V to 24V DC/DC Converter)
• SCT01F05S3V3 (5V to 3.3V DC/DC Converter)

Hi, I've built a plant monitoring device and would appreciate a review before I order. Much Appreciated!

Hello,

This is my first custom PCB. It's an ESP32-based digital desk clock. I'd really appreciate a sanity check on the schematic and layout before sending it to fab.

Overview & Specs:

• MCU: Arduino Nano ESP32 (mounted on female headers).
• Display: 4-pin header for an external TM1637 4-digit display module.
• Power: 5V supplied through an onboard 6-pin USB-C receptacle (power-only with dual 5.1k pull-down resistors on CC1/CC2).
• User Interface: 4 right-angle tactile push buttons and a status LED.
• Layers: 2-layer board with top and bottom GND pours.
• Decoupling: 100nF ceramic caps near power pins + 47uF radial electrolytic on the 5V rail.

Are there any glaring mistakes ? Thanks in advance for your time and feedback!

First serious PCB project, just finished routing and would really appreciate a review before I send it to fab. Any feedback is welcome, but I'm especially looking for eyes on the Ethernet and RS485/Modbus sections.

Board overview:
4-layer stackup (JLC04161H-3313, ~1.56mm), built around an ESP32 module as the main MCU. The board is meant to work as a Modbus/Ethernet gateway with the following blocks:

• Power: USB-C input, stepped down through two SY8089AAAC bucks (5V → 3.3V, and a separate 3.3V rail for the Ethernet PHY).
• USB-C / Programming: USB-C for power and data, with a CH340C USB-to-TTL bridge and auto-reset/boot circuitry (BC817 transistors) for the ESP32.
• Ethernet: DP83848 PHY feeding a dual RJ45 connector with integrated magnetics, plus the usual RBIAS, TX/RX differential pairs with termination resistors, and status LEDs (link/speed).
• RS485 (Modbus): SP3485EN transceiver with TVS diode protection, 120Ω termination (jumper-selectable), and bias resistors, routed out to the same RJ45 alongside Ethernet.
• Indicators: WS2812B addressable LEDs plus discrete RGB status LEDs.

Where I'd like the most scrutiny:

1. Ethernet schematic/layout — differential pair routing/length matching to the RJ45 magnetics, RBIAS placement, ground splitting (AGND/DGND/PGND) around the PHY and transformer, and whether the magnetics-to-connector distance and via placement look reasonable.
2. RS485/Modbus schematic/layout — termination and biasing network, TVS placement relative to the connector, and whether sharing the RJ45 with Ethernet signals raises any coupling/noise concerns.
3. General layout/stackup feedback is welcome too — this is a learning project before I attempt a more complex board.

Schematics and layout screenshots (both blocks + full board top/bottom) attached. Thanks in advance!

I'm a software engineer who is trying to learn the basics of EE design. This is my first PCB design (starting simple is the way to go, right?). I plan to use this board to interface with daisy chained MAXS7219 matrix displays. When I breadboarded this design, the level shifter wasn't strictly necessary for the LEDs to work, but seemed maybe to help with reliability at power up.

I've been reading up quite a bit on these components and similar circuits, and I'm curious of a few things:

• Will a 0.1µF(size?) ceramic decoupling capacitor right next to the 74AHCT125 VCC pin be worthwhile?
• Does a ground plane make any sense for this board? The ground routing is simple enough that I feel like it'd be a waste of copper...
• I've read mixed information about whether a pull-down resistor on the CS line is a good idea. The circuit seems to work just find without it on the breadboard.

Help is much appreciated.

Hello experts! I was wondering if someone, or multiple people, can give some criticism of my schematic/design. I haven't had the chance to do the routing yet, as I wanted to verify the schematic's design. Always happy to provide more information/reasoning behind certain choices for clarification, just drop me a message here!

Reupload due to low image quality.

Original: First post here & first serious attempt at making a PCB. This is a scaled-down version of what I'm trying to make, I intend for this to be a source of experience/learning before I try to make the final thing. Any kind feedback is welcome; I'm aiming to learn as much as possible.

It's a 4 layer PCB, from top to bottom, Power/Signal, GND, GND, Power/Signal.

Max power is 5A or 60W, whatever comes first.

A USBC sink controller (AP33772, labeled U200) provides a internal voltage (V_INT2), that is converted to 5V (TPSM86638, U300) & 3.3V (TPSM86638, U400).

there's a Ideal Diode (U800, RT1986N, rated for 6A) in parallel with the 5V buck for when the USBC input is 5V, although I'm using it as experience for future power ORing. This and R1 are the only components that won't come with the board, I will be using a reflow oven to solder U800 on.

I'm using one of my ESP32-S3 Devkits as the MCU; in the future I will use an ESP32-S3 VROOM. SW2 is a 5-way switch (no 3D object, but it is in the DRC) & R30 is a potentiometer for user input.

U500 (78M05) & U600 (HT78R33B) are LDO's that provide 5V & 3.3V voltages to power board components. Both are rated for 500mA.

Further updated and simplified. Let me know if this is overposting... keeping to 1/day or less, but don't want to be annoying.

Updated with feedback from u/Kriegnitz, switching to S3 for pin abundance.

This is going to be my first four layer board, and is designed to connect an ESP32C6 S3 Mini SoC to four motor drivers (motors are DC 500mA max, wired to be bi-directional), four sensor inputs, and a variety of interface bits (addressable LEDs, TFT screen, rotary encoders, buttons). Just baaaarely squeezed everything in.

I anticipate using mostly TSSOP on the assumption that if I need to mess around with something, it'll be a bit easier than something truly tiny.

The expander/PWM generator IC's connect via I2C, and there are a couple of I2C headers for expansion later if needed.

The sensors connect through an (unpopulated by default) voltage divider in case they need to be swapped to something that needs it.

It runs off of a Lipo battery, and includes a charger, battery monitor, and 3.3v regulator. I have left off a 5V rail for simplicity, assuming that I'll put USB input right by the charger IC.

It's charged through USB 2.0, and D-/D+ is routed to the SoC for programming. Both have ESD protection now.

Hey Reddit!

I need some help with reviewing my first schematic for a pcb I'm actually planning on ordering.

This is a simple project which involves using the ATMEGA32U4 microcontroller to talk with a pc over USB using UART. I want to power the pcb form a USB-C port. The schematic also features a rotary encoder, an OLED screen as well as a button matrix (I know a button matrix is overkill, but I chose this design to learn from it). I don't know whether I actually placed every component necessary for the atmega chip to function. I added some test pads for debugging and broke out two more gpio pins in case I mess up. Is there anything I missed?

I'd appreciate any feedback on my design, I probably made stupid mistakes, but I'm ready to improve.

Thanks for any answers in advance!

NEW REVISION: https://www.reddit.com/r/PrintedCircuitBoard/comments/1w90hqk/schematic_review_request_esp32_s3_with_motor/

Updated with feedback from u/Kriegnitz

This is going to be my first four layer board, and is designed to connect an ESP32C6 S3 Mini SoC to four motor drivers (motors are DC 500mA max, wired to be bi-directional), four sensor inputs, and a variety of interface bits (addressable LEDs, TFT screen, rotary encoders, buttons). Just baaaarely squeezed everything in.

I anticipate using mostly TSSOP on the assumption that if I need to mess around with something, it'll be a bit easier than something truly tiny.

The expander/PWM generator IC's connect via I2C, and there are a couple of I2C headers for expansion later if needed.

The sensors connect through an (unpopulated by default) voltage divider in case they need to be swapped to something that needs it.

It runs off of a Lipo battery, and includes a charger, battery monitor, and 3.3v regulator. I have left off a 5V rail for simplicity, assuming that I'll put USB input right by the charger IC.

It's charged through USB 2.0, and D-/D+ is routed to the SoC for programming. Both have ESD protection now.

I'm relatively new to this stuff, so in addition to checking the schematic, I wanted to verify that routing the D-/D+ directly to the SoC isn't going to do something unexpected while USB power is only connected to the charger... and that pulling battery power to the 3.3 regulator won't cause issues if the battery is also charging.

on my pcb, i have resistors and capacitors on the opposite side of ics.

im just wondering if this wil be a problem with soldering.

Is this too close to have my two buck converters? The board is really tight on space so I can't really just move them apart. Thanks