Hey guys I'm trying to learn how to design PCB's. This is a design that I recently did for a servo module. What should I improve on?

Hi everyone!

I am building a CR Box, inspired by many designs on the r/crboxes subreddit.

This is my first ESP32-based design. I did the layout on 2 layers because I haven't used many components, and the highest intended signal frequency is the 25 kHz fan PWM (apart from the buck converter). I have tried my best to keep the bottom GND plane as intact as possible.

The fans are divided into two groups, A and B, to control the speed of the two fan groups separately. The ESP32 controls two MOSFETs using PWM, and each MOSFET is connected to the PWM pins of five fans. I added these 2 little MOSFETs to protect the ESP32 pins because, as far as I understand, the fans have an internal pull-up on their PWM pins, which can be as high as 5.25V. I added a "smart mode" switch, which, when OFF, lets me control the fans manually using the potentiometer. When the switch is ON, the controller will receive data from an air quality sensor and adjust the speed based on that. In addition, I connected each tachometer pin to the ESP32 to monitor the RPM of each fan and detect if one stops spinning.

For the power supply, the input voltage is 12 V. I added a P-channel MOSFET for reverse-polarity protection and a buck converter to step down the 12 V to 3.3 V to power the ESP32.

I designed the controller to support up to 10 fans. Each fan I am planning to use draws up to 0.35 A, giving 3.5 A in total. So I used a copper pour for the 12 V rail and wide traces towards the fan headers.

The PCB will be mechanically supported by the switch, potentiometer, and four M3 screws.

I’ve attached 3D renders of the board, the schematics, and the complete PCB layout.

I'd really appreciate any comments or advice on the design. I'm especially interested in feedback on how I control the fan speeds using PWM. Does the overall layout look okay? Are there any other issues or things you would change before I manufacture the PCB?

Thank you! 😊

System Architecture Overview

This schematic details an externally powered USB-C hub featuring DisplayPort Alternate Mode, dual USB-A downstream ports, and Gigabit Ethernet capability. The design is bound by a strict operational constraint: the hub must be powered externally and must not deliver power to the host device (phone) under any circumstances.

Functional Subsystems

1. USB-C Interface and DisplayPort Alt-Mode

• Protocol & Switching Control: USB-C Power Delivery (PD) and Alternate Mode negotiation are handled by the LDR6023SS controller. High-speed signal routing for DisplayPort Alt-Mode is multiplexed via the HD3SS460 switch.
• Power Isolation Topology: To enforce strict isolation, the host phone's VBUS line (usbc_VBUS) powers only the LDR6023SS. There is no electrical path connecting the hub's main power rails back to the phone's VBUS line, eliminating any possibility of back-powering the host.

1. Downstream Connectivity and Hub Expansion

• USB-A Ports: The TUSB8044ARGCR hub controller expands the upstream data connection into downstream interfaces, managing two physical USB-A 3.1 Gen 1 ports.
• Gigabit Ethernet: One of the downstream USB 3.1 channels from the TUSB8044A interfaces directly with a LAN7800 USB 3.1-to-Ethernet bridge to provide a dedicated 1Gbps network connection.

1. Power Generation

• External Power Supply: Except for the host-powered LDR6023SS, all internal subsystems (including the 3.3V, 2.5V, 1.2V, and 1.1V rails) are derived strictly from an external power block
• mux- HD3SS460- https://www.ti.com/lit/ds/symlink/hd3ss460.pdf?ts=1793132125218&ref_url=https%253A%252F%252Fwww.google.com%252F
• PD_negotiator- LDR6023ss- http://usbtech.net/upload/portal/20210129/713dd1a429631eed99f86d1b3961ad7d.pdf
• usb_hub- TUSB8044ARGCR- https://www.ti.com/lit/ds/symlink/tusb8044a.pdf?ts=1793125680672&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTUSB8044A
• ethernet- LAN7800/Y9X- https://ww1.microchip.com/downloads/aemDocuments/documents/UNG/ProductDocuments/DataSheets/LAN7800-Data-Sheet-DS00001992.pdf

I am trying to get my toes in the water of PCB design, and came up with this board to connect two TMC5240s to an STM32F7 to drive stepper motors. Board is simple for now, but will eventually have other versions with the drivers and stm on board.

Hi everyone, I've built an MPPT for a college project. The control and PWM signals are managed by an STM32G474 on another board. Please share your thoughts and advice—I'd like to improve it :)

Hello there!

Hi, my name is Jose Ramirez and I'm a Computer Engineering student, and this is my first PCB ever (the real first one is a FPC to male PIN adapter for a joystick) and It's also my bachelor's thesis.

Why? Because the PSP was the console of my childhood, and building my own take on it is my way of paying tribute to it. (Yes I know that it will have 2 joysticks and it will look more like the PSVita 😅 ).

I have almost no electronics background, so a lot of what I've learned this 2.5 months I have been working in this project the way has been with AI as a tutor, and some YT videos. I used it to understand datasheets, develop and review the schematics, and to understand how to route and the reason of the position of every component. Even though I have been using AI to understand the project everything has been developed by hand, no AI automation has been used for developing this project, doing it this way I think that has lead me to gain more knowledge.

I want to know every possible mistake and every standard practice I haven't followed. I want to improve every detail, no matter how small.

Components

- MCU: ESP32-S3-DevKit.

- Display:BT817Q graphics controller with a flash memory (16MBytes) and a 12 MHz crystal. It controls the 800×480 RGB panel through a 40-pin FPC, and the capacitive touch through a 6-pin FPC

- ESP32 ↔ BT817: QSPI, ≤ 30 MHz.

- BT817 ↔ flash: 60 MHz.

- Backlight: DIO5661 boost, constant current, ~60 mA at ~21 V.

- Power: USB-C (J10), 5 V only, with 5.1 k CC pull-downs and USBLC6-2 ESD protection (U2). 5 V feeds an LMR51430 buck (1.1 MHz version, 2.2 µH) for the 3.3 V rail.

- Input: MCP23017(0x20) over I²C for 14 buttons, plus two analog joysticks on FPCs directly connected to the ESP32 ADC.

- Audio: PAM8302A class-D amplifier with a ferrite and a output filter, speaker on a JST PH connector.

Board info

- KiCad [10.0.6]. 4 layers: F.Cu signals / In1 solid GND / In2 solid 3.3 V / B.Cu signals.

- DRC: 0 errors, 0 unconnected. Four items are excluded on purpose:

- 2 "unconnected" items on U2: flow-through routing as in ST's datasheet (pins 1–6 and 3–4 are joined inside the chip)

- ERC: 0 errors. 4 excluded warnings.

Is this prototype able to work if I sent it to fab?

- Github repo: https://github.com/ocxpke/ocx

Thanks a lot for taking the time, any comment will be appreciated! :D

Hey everyone, I'd love a schematic review before I start the layout.

I am designing a little logger for diagnosing car engines for a class. An accelerometer board goes on the engine to pick up vibration, and a spark detection board goes on an ignition coil to check that it's firing (kind of like a coil-on-plug tester). Both connect to the main ESP32 board with wires, so it's 3 separate PCBs.

Main board (ESP32-WROOM-32E):
- USB-C with a CP2102N for programming
- Single-cell Li-ion with a BQ24072 charger and MAX17260 fuel gauge
- AP7361C 3.3V regulator with an external on/off switch
- Optional connector for a NEO-7M GPS module

I've used this same ESP32 + CP2102N auto-reset setup before, but auto flashing never worked. I had to hold the BOOT button every time I wanted to upload code. If anyone can spot why, that'd be awesome.

Accelerometer board:
- KX134 (±64g) over SPI

Spark detection board:
- Pickup wire to RC filter, TVS and clamp diodes to 74HC14 Schmitt trigger to ESP32

Any feedback is welcome, thanks!

hello everyone, I’ve made my own Arduino, what do you guys think of my work? I’m very open to your criticism on what I should revise or change. I’m honing my skills so it would really be helpful to know what you have to say.

I have a bad position where I would be running two parts into each other. Soldered from opposite sides of the board, can not be moved.

On 1, that's a little offset of the annular ring up from the slotted hole. Leaving .4mm copper to copper. Not ideal.

On 2, that's a big push. This breaks a lot of design rules, but, I wouldn't care if during mfg this wasn't plated exactly all around because it's going to make connection on the three side for sure.

On 3, that's extreme on purpose. No design rule checker will like this... But I'm not sure what would happen at a JLCPCB or PCBWay. If there is a reason to do this sometimes. I wouldn't even care if the lower tail of that hole is plated if the three sides were mostly.

This is just signal level current, and all I need is the connection. No force, no heat, no vibration. I just wouldn't want weird issues because of a failed plating operation. Is it possible to do this?

This is my first pcb, a rocket fligth computer. I used a 4 layer layout with Signal-GND-Power-Signal stack. I poured gnd to the top and bottom layer and stitched gnd vias. The mosfet and the terminal block for the ejection charge will be on the second board. Is this board ready for manufacturing?

Note: It's Flight* lmao, sorry for the typo

A few questions I have about copper pours, beware I don't have any traditional education in this field, basically learning by doing. These questions assume a 4-layer board with SIG-GND-PWR-SIG stackup and effects on RF are also important.

Can I use copper pours basically as a replacement for traces where there is enough space, are there any downsides besides of course when dealing with impedance matching? Copper pours use the maximal area given to them while respecting clearance and whatnot, so it can have lower resistance than a specific trace, though that can result in them having "wavy" borders.

Similar question, are there any downsides to connecting a bunch of GND pins (resistors and/or caps for example) together using a copper pour while still giving each of them a close via to the GND plane i.e. a small GND plane on the top layer connected to the actual GND plane using vias? Or is it best to connect them individually to their vias using traces?

What about connecting multiple pins together with both a pour and traces?

This is my attempt at creating a rocket flight computer. This is built around the STM32F405. The mosfet will be on another board as well as the terminal block for the ejection charge. The telemetry module will also be on another board. The stm32 will communicate with the second board through the esp32 c3 super mini rx and tx.

Hello, this is my first PCB i've designed on my own and wanted to get some feedback on it and see if anyone has any advice. The board will be used on a race car to connect to the CAN bus from the ECU and using the ESP32 i will program logic to turn on certain LEDs based on the engine's RPM. A bit more specific info on it:

• it's going to be used in automotive application, in harsh racing conditions (vibration, heat, moisture, etc.)
• The 12V input is the automotive 12V power wire and it grounds to the chassis ground at the end of the harness
• The CAN network it connects to doesn't terminate at the board, but close to it
• The LDOs i chose were somewhat random but regulate to the 5v and 3.3v needed for the CAN transceiver and ESP32 respectively
• I'm planning on programing the ESP 32 w/ a separate dev kit board that I've made in one of my PCB design classes
• The LEDs are being powered directly by digital IO pins on the arduino, this feels wrong but I didn't wana add a bunch of transistors for them

If anyone has advice on how to make the board not 4 layers I'd appreciate that, I'd love to be able to save the money but wasn't sure how to make it happen without making a bigger board or having lots of extra vias.

I'm also looking for any advice with the routing/trace width selection & design given the automotive application, should I be worried about anything with the starter motor noise on the circuit, etc.

Any advice or tips to help me improve would be greatly appreciated. Thanks!

This is the driver board for a BLDC air purifier fan to handle motor control as well as ARGB (maybe WS2812b or equivalent). This board screws directly behind the motor I am using, hence the integrated encoder. I intend to make another board that plugs on top with an esp32 and a display so I can do some smart home integration next time.

Driver: DRV8316C

MCU: STM32G431

Input voltage: 12V

Motor max. current: <2A at max speed based on testing

ARGB max. current: <1A (will control number of LEDs accordingly).

I know running close loop FOC for a fan motor is crazy overkill, but I can't find any suitable DC motors to drive the 200mm fan. Most ESCs for bldcs are also overspecced and overpriced for this application. Also because I already have some of these bldc motors just lying around.

I used a bunch of mlccs near the driver power input mainly to avoid tall components. The original design had an electrolytic for more bulk capacitance, but it interfered with the board ontop.

I also tried to cramp everything on the top layer since I am reflow soldering this myself on a hotplate. The bottom few passives could be done with a heatgun, and the ic just using an iron.

This is my first time designing a carrier board. I have included the following:

• RJ45 connector (without Ethernet functionality)
• USB-C port for power delivery (USB PD)
• USB-A 3.0 port
• Two MIPI CSI camera ports

Thank you!

Hi guys, I'm a beginner in pcb. Kindly review this and suggest changes. This is a DC to AC Inverter circuit

Hey all,

I designed this keyboard PCB and was looking for any tips on how I could improve it, or if it will serve my purposes as it sits.

It is meant to be an nRF52840 (via an MDBT50Q-1MV2) powered Bluetooth and USB enabled keyboard with a built in I2C trackpad, featuring an onboard battery and charging circuit. I also intend to run ZMK on it.

This is my first PCB that I ever intend to get manufactured, so I would appreciate any feedback you have. The link to the GitHub repo for this keyboard is here within the Keyboard-PCB directory.

Thank you guys all so much in advance!

I’m designing a PDB for a drone and would appreciate some feedback before taking the layout further.

The design uses:

• A 14S battery input, up to 58.8V fully charged
• Two LM70660 buck converters targeting 5V and 12V at 6A each
• An INA228 with an Eaton 100µΩ, 15W shunt for battery monitoring
• An I²C power connection for Battery Monitoring
• A four-layer PCB

The battery distribution target is 200A continuous, with roughly 240A peaks for a few seconds. This is a design target, not a tested rating.

I’ve included the schematic, individual copper layers and 3D views.

I’m particularly looking for feedback on the buck converter placement/routing, ground return paths, shunt Kelvin connections and high-current copper paths. Any obvious mistakes or things you’d change?

The scenario is this: you are doing an outdoor solar project (including the panel, a battery up to 12V, a MCU and the load), normally during prototyping trying to hook up all the sensors needed can be a bit of a hassle and disorganized. Or you want to know the other parts of your project work right while you test / design one part eg a BMS or charger or MCU or even a load. That's kind of the idea behind this board.

This is also a personal project for me, through which I get better at electronics and PCB design.

Features:

• Can measure voltage and current (get power, energy and possibly charge and discharge rate from that) for MCU, load, battery, solar
• Can measure lux levels
• Can keep time with onboard RTC
• Had onboard slot for micro SD card for storing data (optional)
• Max 1A 5V or 3.3V for MCU
• Load is getting voltage straight from battery basically (goes through an INA236 for measurement first) so variable voltage but 2A max
• Max 24V battery
• Max 3A (subject to change) about 24V max solar panel 
• Can measure temp, humidity, pressure through BME280

Main parts used:

• XT60 connectors for solar and battery input and output (I have input and output so you can connect the battery and solar panel(s) to an external charger
• MP5042GJ-P (for limiting current to 2A, it goes to max 28V and is connected to the main load output from the battery)
• LMR36510ADDAR (buck converter to 5.5V, 1A. This feeds into the regs for the 5Vand 3.3V MCU outputs)
• AP2115M-3.3TRG1 (LDO going down from 5.5V to 3.3V, max 1A for a 3.3V MCU)
• MAX38903BATB+T (LDO going down from 5.5V to 5V, max 1A for a 5V MCU)
• 4 INA236 (for current and voltage measurements for load, MCU [have to choose if you're using 3.3V or 5v], battery, solar)
• BME280 (for surrounding temp, humidity, pressure sensor)
• VEML7700-TT (for surrounding lux sensor)
• MCP7940M-I_SN (RTC for keeping time like when you're logging data and want time stamps)
• SD card holder (in this case, it's a BXCONN TF-CARD-9P for now)
• Fuses for the solar and battery (ANR-7.5)

Operation:

You plug in the solar, battery. The MCU outputs that are 1A max, power the MCUs. There are also terminals (5V or 3.3V) for the VCC of the sensors. If you have a 5V MCU, connect 3.3V 1A output to 3.3V VCC then that powers the 3.3V sensors and you can connect to I2C and SPI like normal. If you have 3.3V MCU, put jumper on J6 since all 5V sensors can be powered by 3.3V. Use I2C and SPI lines as normal.

Connect the load. Insert SD card if you want and ofc, you'd have programmed the MCU.

Ok, so schematics (I used multiple pages and global labels so hopefully, this isn't too bad):

2A load limiter:

Buck converter to 5.5V, max 1A:

3.3V MCU output:

5V MCU output:

INA236's:

SD Card:

RTC:

BME280:

VEML7700:

I2C, SPI lines:

Schematics:

The PCB:

4-layer board going SIG --> GND --> GND --> SIG

I know this likely not the most optimal layout, I'm not too experienced but this the first version, I'm really just wanting it to work first then I can reiterate, optimize etc?

The groups of vias around (none are smaller than 0.3mm via hole and 0.6mm via diameter) are GND for thermal relief

Thank you all. I appreciate any feedback.

Hey everyone, this is part 2 of my fuel pump / fuel level / speed sensor CAN node for my old BMW E30. First of all thanks alot for all the feedback on the first post, specially to u/GuidancePCB, u/mariushm and u/saltyboi6704, you guys made me rethink a bunch of stuff and the board is way better now.

Quick recap: board goes under the rear seats (inside the cabin), drives the fuel pump (~12A) with a BTS7004 high side switch, reads the stock fuel sender and the diff VR speed sensor and sends everything over CAN to the other nodes im planning (around 8). Personal use only, no homologation. The car has a battery cut off switch so the nodes are dead when its parked, and I left load dump out of scope on purpose (i know, i know).

What I changed:

• Input protection: the TVS was after the reverse polarity diode, so a negative spike would land straight on the SS16 (only 60V). Now its a bidirectional SMBJ26CA before the diode, and the diode is a SS110 (100V) for extra margin.
• BTS7004 supply: someone pointed me to load dump/negative pulses and after reading the infineon datasheet properly i realised the BTS VS had no TVS at all (they show a ~33V TVS on VS in the app circuit). Added a unidirectional SMBJ24A right at VBAT next to the switch. R_GND (47R) is now 0805.
• Buck input caps: you were right, 10uF X5R 1206 at 14V is way less than 10uF. Now its 100uF electrolytic (damping) + 2x 10uF X7R 1206 + 2x 220nF, and the small ones sit right at each VIN/PGND pin pair. I also redrew them next to the buck in the schematic, it was confusing before, sorry about that.
• Kept the LMR36015 instead of the LMR43610-Q1 / RTQ2104. Both look nice but they top out at 36V and the TVS clamps around 42V, so i’d be at the limit. The 60V part gives headroom, and JLC assembles it so the QFN isnt a problem for me.
• CAN: removed the common mode choke. Kept a single 120R with a jumper because i dont know yet which nodes will be at the bus ends, and split termination with one jumper leaves the bus unbalanced when its open. The resistor is 1206 now in case CANH gets shorted to 12V.
• Clock: swapped the 8MHz crystal for a 3.3V CMOS oscillator into PF0 (HSE bypass). Turns out the crystal i picked had 250 ohm ESR and the gain margin was pretty bad, so thanks for that one.
• VREF: didnt use the internal VREFBUF. The fuel sender reading is ratiometric (I read both ends of the 150R reference resistor) and the reference node sits around 3.0V, so the 2.9V max internal ref would clip it. The 3V3 noise cancels in the ratio anyway.
• Schematic: FB is wired directly and PG uses a proper net label now.
• Bulk caps near every IC: didnt do this one. Its a small 62x72mm board, the 3x22uF buck output caps are only a few cm away and each IC has its decoupling per datasheet.
• 4 layers: Top / solid GND / signals / Bottom. Pump and power pours on the outer layers, buck hot loop, clock and CANH/CANL on top. Added a lot of GND stitching vias, VBAT vias next to the BTS pad and 0.5mm copper to edge.
• Added 3 debug LEDs (run / rx / tx)

Updated schematic and PCB attached. Any feedback is welcome, specially on the layout. Thanks again!

This message has been translated and corrected by an AI from Spanish to English. Neither the schematic nor the PCB was designed or built by an AI. I want to avoid any comments about the use of AI because the only use I’ve made of it—aside from the translation for this platform—is to compare different components and datasheet entries so that it could point out the differences between them.

Thank you very much for your advice to the users mentioned, as well as to future users and those not mentioned.

Hello, I've designed this circuit board that will sit next to my heating vents and open and close them to better control the temperature in each room, built around an ESP32-H2-MINI-1U. The temperature of the vents means that regular Li Ion batteries may degrade, so I've gone for an LiFePO4 cell instead.

I've done my best to follow each chip's circuitry, but let me know if I've messed up

ESP32 H2 MINI 1

MCP73123/223

TPS613222ADBZ

I'm planning on using a hot plate, along with a stencil and solder paste to solder the surface mount components. This will be my first time doing this, so any advice is appreciated.

Hello, I wanted the kicad for the breakout board of pcm1808 that I bought online.

I could not find the project online, decided to re-create it for learning.

I used a multimeter to check what is connected to what, now I would like some feedback on what I came up with.

1. How does my layout look on the pcb? Do I have too many gnd vias or not enough?

In the doc, they recommend that I put vias underneath the pcm1808 as well as around it a bit.

My traces width is .2mm, I wont go over 10-20mA current. Looking for feedback to become more professional.

1. Does the sch look ok? Looking for feedback to become more professional here as well.

2. vref just goes to a few capacitors then to ground, does this make sense?

3. I noticed on Reddit someone had an issue with the board they bought. They mentioned that one of capacitor was incorrect. I had no issues with my board I bought online, but I did notice the resistor going to LIN and RIN are 10k, which is much higher than the one recommend in the ti doc. Which I believe they also used the wrong capacitor for it. I went with what the doc said: (1 kΩ and 1000 pF). Is that a correct assumption?

Reddit post titles talking about the same findings: warning_about_fake_pcm1808_adc_chips_on_modules and pcm1808_modules_from_china_the_drama_continues

1. In the doc, they recommend having grnd plane between clck signals. I have small islands with ground vias in between, is that enough? Some of the clck signals just have a gnd plane underneath, is that enough?

2. My top and bottom layer are both net ground zones, is that ok?

3. Does my bom look ok? (attached)

If you search for ti pcm1808, the section "9 Power Supply Recommendations" has all the info about vref, RIN, LIN, etc.

Just trying to get better at this, thank you in advance!

my first ever pcb desing and i would love to know if i do anything mayor incorrectly?

It recieves 12v in and the buck converter steps it down to 5v for the xiao esp32-c6.

the esp32 is controlling 6 fans en reads 2 onewire ds20b18 sensors.

i wil be adding mounting holes later when i implemented al fixes

Please let me know if there is anymore info required.

Hi, I've designed a board that monitors temperature, humidity and absolute pressure and displays the data on an E-Ink display. The board is powered by a Li-Po battery which can be charged through an on-board charger circuit.

The heart of the system is the STM32L422KBT6 MCU which communicates with the SHT40 temperature and humidity sensor and the LPS25HBTR pressure sensor. I've chosen E2271KS0C1 E-Ink display whose control circuitry has been designed according to the datasheet.

Li-Po battery (pouch style) will probably have 1500mAh capacity (not yet decided). The BQ29700 IC is used for battery protection, while the BQ25185 IC is used for charging and power path circuitry. Resistors R17 and R18 form a voltage divider for lowering the battery voltage, which can then be sampled with MCU ADC (battery voltage monitoring). Transistors Q2 and Q5 are used, so the divider current can be cut off when not used. Battery voltage or 5V USB-C voltage when charging is then stepped down to 3V with an LDO.

Should i make a 4 layer board instead? Are there any obvious mistakes that I'm missing?

Any feedback would be greatly appreciated.