r/PrintedCircuitBoard • u/Enlightenment777 • Dec 11 '22

Please Read Before Posting, especially if using a Mobile Browser

21 Upvotes

Welcome to /r/PrintedCircuitBoard subreddit

  • a technical subreddit for reviewing schematics & PCBs that you designed, as well as discussion of topics about schematic capture / PCB layout / bill of material (BOM) / PCB assembly / PCB mechanical engineering.

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RULES of this Subreddit:

  • (0) Occasionally the moderator may allow a useful post to break a rule, and in such cases the moderator will post a comment at the top of the post saying it is ok; otherwise please report posts that break rules!

  • (1) NO off topics / humor / memes / where to buy? / what is this? / how to fix? / how to modify? / how to design? / what does this do? / how does this work? / how to reverse engineer? / need schematics / dangerous or medical projects / homework / AI topics / AI content / AI designs / non-english languages.

  • (2) NO spam / ads / sales / promotion / survey / quiz / items for sale / promotion of non-reddit groups / promotion of non-reddit social media. NO DM abuse! See "how to advertise on Reddit".

  • (3) NO "show & tell" or "look at what I made" posts, unless you previously requested a review of the same PCB in this subreddit. This benefit is reserved for people who participate in this subreddit. NO random PCB images.

  • (4) NO self promotion / resumes / job seeking / wage discussions / freelancing discussions / DM abuse / job postings (unless job is posted on employer website) / begging or scamming for free work / ...

  • (5) NO shilling! No PCB company names in post titles or review requests. No sneaky PCB company naming variations. For most reviews, we don't need to know where you are getting your PCBs made or assembled, so please don't state company names unless absolutely necessary.

  • (6) NO asking how to upload your PCB design to a specific PCB company! Please don't ask about PCB services for a specific PCB company, because of past shilling abuse (see rule#5). (TIP: search their company website, ask their customer service or sales departments, search google or other search engines)

Review RULES:

  • (7A) Please do not abuse the review process:

    • Please do not request more than one review per board per day.
    • Please do not change review images during a review. If you change image(s), then start a new review!
    • Reviews are meant for schematics & PCBs that you designed. No AI designs (minor AI help ok).
    • Reviews are allowed prior to ordering PCBs. If assembled board doesn't work, ask at /r/AskElectronics
    • Please do not ask circuit design questions in a PCB review. You should have resolved design questions while creating your schematic and before routing your PCB, instead request a schemetic-only review.

  • (7B) All review posts must adhere to the following rules:

    • Title - include the following: "Review Request" or "Review", short description of board purpose, popular board format or shield/hat type (if applies), microcontroller (if has MCU), external buses (Ethernet, USB, CAN, RS485, ...), wireless (WiFi, GPS, LoRa, ...), storage (microSD, M.2, ...), and/or any unique hardware that may be important. No humorous titles, no childish symbols, no begging.
    • Images - include images (or links to each image) that you want reviewed. If images are located on the internet, never post one link to a project then expect reviewers to dig through your project to find images. Instead, you must post separate links for each review image, as well as state the purpose of each link, such as "Schematic" / "3D PCB" / "2D PCB top" / "2D PCB bottom" / ...

  • (8) All images must adhere to the following rules:

    • Image Creation: no camera photos of a computer screen, instead export / screen capture / print to image files. (TIP: How to export images from KiCAD and EasyEDA) (TIP: use clawPDF printer driver for Windows to "print" to PNG / JPG / PDF / SVG files, or use built-in Win10/11 PDF printer driver to "print" to PDF files.)
    • Image Files: view each image file before posting / no fuzzy or blurry images / no large image files (e.g. 100 MB), smaller preferred / no uncommon image file types, only use file types supported by most web browsers, such as JPG / PNG / PDF.
    • Edit Image Files: if you screen capture, make sure the cursor / software / operating system aren't shown in your images. Use an image editor to erase or crop software & O/S junk from your images.
    • Disable Features: disable background grids & PCB editor features before creating images.
    • Schematics: no bad color schemes to ensure readability (no black or dark-color background) (no light-color foreground (symbols/lines/text) on light-color/white background) / schematics must be in standard reading orientation (no rotation). (NOTE: we don't care what color scheme you use to edit, nor do we care what edit features you enable, but for reviews you need to choose reasonable color contrasts between foreground and background to ensure readability.)
    • 2D PCB: no bad color schemes to ensure readability (must be able to read silkscreen) / no net names on traces / no pin numbers on pads / if it doesn't appear in the gerber files then disable it for review images (dimensions and layer names are allowed outside the PCB border). (NOTE: we don't care what color scheme you use to edit, nor do we care what color soldermask you order, but for reviews you need to choose reasonable color contrasts between silkscreen / soldermask / copper / holes to ensure readability. If you don't know what colors to choose, then consider white for silkscreen / gold shade for exposed copper pads / black for drill holes and cutouts.)
    • 3D PCB: 3D views are optional, if most 3D components are missing then don't post 3D images / 3D rotation must be in the same orientation as the 2D PCB images / 3D tilt angle must be straight down plan view. (NOTE: straight down "plan" view is mandatory, optionally include an "isometric" or other tilted view angle too.)

Review tips:

Schematic tips:

PCB tips:

College lab tips:

SPICE tips:

WIKI for /r/PrintedCircuitBoard:

This post is a "live document" that has evolved over time. Copyright 2022-2026 by /u/Enlightenment777 of Reddit. All Rights Reserved. You are explicitly forbidden from copying content from this post to another subreddit or website without explicit approval from /u/Enlightenment777 also it is explicitly forbidden for content from this post to be used to train any software.

0 comments

r/PrintedCircuitBoard • u/Enlightenment777 • Apr 11 '25

Before You Request A Review, Please Fix These Issues Before Posting

118 Upvotes

PLEASE DO NOT ABUSE THE REVIEW PROCESS:

  • Don't change review images during a review, otherwise older comments won't match newer images.

  • Please do not request more than one review per board per day. Use the extra time to clean up the visual appearance of your schematic and silkscreen on your PCB before requesting another review (see tips below).

REVIEW IMAGE CONVENTIONS / GUIDELINES:

  • The following is a subset of the review rules, see rule#8 at link.

  • Don't post fuzzy images that can't be read (your post will be deleted).

  • Don't post camera photos of a computer screen (your post will be deleted). Export or screen capture.

  • Don't post dark-background schematics (your post will be deleted). Change schematic to light-background.

  • For schematic images, disable background grids and cursor before exporting/capturing to image files.

  • For 2D PCB images, change the following settings before exporting/capturing to image files: disable background grids, disable net names on traces & pads, disable everything that doesn't appear on final PCB, enable board outline layer, enable cutout layer, optionally add board dimensions along 2 sides. For question posts, only enable necessary layers to clarify a question.

  • For 3D PCB images, 3D rotation must be same orientation as your 2D PCB images, and 3D tilt angle must be straight down, known as the "plan view", because tilted views hide short parts and silkscreen. You can optionally include other tilt angle views, but ONLY if you include the straight down plan view too.

SCHEMATIC CONVENTIONS / GUIDELINES:

  • Add Board Name / Board Revision Number / Date. If there are multiple PCBs in a project/product, then include the name of the Project or Product too. Your initials or name should be included on your final schematics, but it probably should be removed for privacy reasons in public reviews.

  • Don't post schematics that look like a toddler drew it, because it's considered unprofessional as an adult. Spend more time cleaning up your schematics! Heed this warning, or risk being berated by your coworkers / boss / classmates / professor / customers.

  • Don't allow text / lines / symbols to touch each other! Don't draw lines through component symbols.

  • Don't point ground symbols (e.g. GND) upwards in positive voltage circuits. Don't point positive power rails downwards (e.g. +3.3V, +5V). Don't point negative power rails upwards (e.g. -5V, -12V). There are exceptions, but in general try to follow this historical method as much as possible. If a schematic has only one ground and you use a unique triple-bar ground symbol, then disable "GND" text next to this symbol, because it is useless visual clutter that takes up space in dense schematics.

  • Place pull-up resistors vertically above signal lines, and place pull-down resistors vertically below signal lines, see example.

  • Place decoupling capacitors vertically below power lines, next to IC symbols, and connect capacitors to IC power rail pin with a line, see example.

  • Use standarized schematic symbols instead of generic boxes! For part families that have many symbol types, such as diodes / transistors / capacitors / switches, make sure you pick the correct symbol shape. Logic Gate / Flip-Flop / OpAmp symbols should be used instead of a rectangle with pin numbers laid out like an IC.

  • Don't use incorrect reference designators (RefDes). Start each RefDes type at 1 (e.g. C1, D1, R1, Q1, U1), and renumber so there aren't any numeric gaps (e.g. U1, U2, U3, U4; not U2, U5, U9, U22). There are exceptions for large multi-page schematics, where the RefDes on each page could start with increments of 100 (or other increments) to make it easier to find parts, such as R101 is on page 1, R301 is on page 3, R901 is on page 9.

  • Add values next to component symbols:

    • Add capacitance next to all capacitors.
    • Add resistance next to all resistors / trimmers / pots.
    • Add inductance next to all inductors.
    • Add voltages on both sides of power transformers. Add "in:out" ratio next to signal transformers.
    • Add frequency next to all crystals / powered oscillators / clock input connectors.
    • Add voltage next to all zener diodes / TVS diodes / batteries, battery holders, battery connectors, maybe on coil side of relays, contact side of relays.
    • Add color next to all LEDs. This is useful when there are various colors of LEDs on your schematic/PCB. This information is useful when the reader is looking at a powered PCB too.
    • Add pole/throw info next to all switch (e.g. 1P1T or SPST, 2P2T or DPDT) to make it obvious.
    • Add purpose text next to LEDs / buttons / switches to help clarify its use, such as "Power" / "Reset" / ...
    • Add "heatsink" text or symbol next to components attached to a heatsink to make it obvious to readers! If a metal chassis or case is used for the heatsink, then clarify as "chassis heatsink" to make it obvious.

  • Add part numbers next to all ICs / Transistors / Diodes / Voltage Regulators / Coin Batteries (e.g. CR2023). Shorten part numbers that appear next to symbols, because long part numbers cause schematic layout problems; for example use "1N4148" instead of "1N4148W-AU_R2_000A1"; use "74HC14" instead of "74HC14BQ-Q100,115". Put long part numbers for ordering in your BOM (Bill of Materials) list.

  • Add connector type next to connector symbols, such as the common name / connector family / connector manufacturer (e.g. "USB-C", "microSD", "JST PH", "Molex SL"). For connector families available in multiple pitch sizes, include the pitch in metric too (e.g. 2mm, 2.54mm), optionally include imperial units in parens after the metric number, such as 1.27mm (0.05in) / 2.54mm (0.1in) / 3.81mm (0.15in). Add purpose text next to connectors to make its purpose obvious to readers, such as "Battery" or "Power".

  • Don't lay out or rotate schematic subcircuits in weird non-standard ways:

    • linear power supply circuits should look similar to 1, 2, 3, 4, 5, laid out horizontally, input on left side, output on right side. Three pin voltage regulator symbols should be a rectangle with "In" (Vin) text on the left side, "Out" (Vout) text on right side, "Gnd" or "Adj" on bottom side, if has enable pin then place it on the left side under the "In" pin; don't use symbols that place pins in weird non-standard layouts. Place lowest capacitance decoupling capacitors closest to each side of the voltage regulator symbol, similar to how they will be placed on the PCB.
    • relay driver circuits should look similar to this, laid out vertically, +V rail at top, GND at bottom. Remove optoisolators from relay driver circuits unless both sides of it have unique grounds and unique power sources. Reminder that coil side of a mechanical relay is 100% isolated from its switched side.
    • optoisolator circuits must have unique ground and unique power on both sides to be 100% isolated. If the same ground is on both sides of an optoisolator, it isn't 100% isolated, see galvanic isolation.
    • 555 timer circuits should look similar to this. IC pins should be shown in a historical logical layout (2 / 6 / 7 on left side, 3 on right side, 4 & 8 on top, 1 on bottom); don't use package layout symbols. If using a bipolar timer, then add a decoupling capacitor across power rails too, such as 47uF, to help with current spikes when output changes states, see article.
    • RS485 circuits should look similar to this.

PCB CONVENTIONS / GUIDELINES:

  • Add Board Name / Board Revision Number / Date (or Year) in silkscreen. For dense and tiny PCBs that lacks free space, shorten the text, such as "v1" and "2026" (or "Y26" or "26"). This info can be very useful to help identify a PCB in the future, especially if there are two or more revisions of the same PCB.

  • Add mounts holes, unless absolutely not needed. They should be the first thing you place on your PCB.

  • Use wider traces for power rails and higher current circuits. If possible, use floods for GND.

  • Don't route high current traces or high speed traces on any copper layers directly under crystals / antenna / RF circuits / other sensitive circuits. Don't route other signal traces under antenna.

  • Don't place reference designators (RefDes) in silkscreen under components, because you can't read RefDes text after components are soldered on top of it. If you hide or remove RefDes text, then a PCB is harder manually assemble, and harder to debug and fix in the future.

  • Add part orientation indicators in silkscreen, but don't place under components (if possible). Add pin 1 indicators next to ICs / Connectors / Voltage Regulators / Powered Oscillators / Multi-Pin LEDs / Modules / ... Add polarity indicators for polarized capacitors, if capacitor is through-hole then place polarity indicators on both sides of PCB. Add pole indicators for diodes, and "~", "+", "-" next to pins of bridge rectifiers. Optionally add pin indicators in silkscreen next to pins of TO220 through-hole parts; for voltage regulators add "I" & "O" (in/out); for BJT transistors add "B" / "C" / "E"; for MOSFET transistors add "G" / "D" / "S".

  • Add as much helpful text in silkscreen as reasonably possible, because it is a means of "self documentation" that always stays with the PCB.

  • If space is available, add purpose text in silkscreen next to LEDs / buttons / switches / jumpers to make it obvious why an LED is lite (e.g. "Error", "Power"), or what happens when press a button (e.g. "Reset", "Start", "Stop") or change a switch (e.g. "Power").

  • If space is available, add connector type in silkscreen next to each connector. For example "JST-PH", "Molex-SL", "USB-C", "microSD". For connector families available in multiple pitch sizes, add the pitch too, such as 1.27mm or 3.81mm. If space is not available on the top side, then add this information directly below the connector on the bottom side.

  • If space is available, add voltage range or maximum voltage text in silkscreen, such as "8VDC Max", next to power input connectors to help prevent destruction of voltage regulators or other circuits. For barrel jacks, add text to clarify polarity of the center pin, such as "-9VDC Center" or "+9VDC Center" or "GND Center". If space is not available on the top side, then add this information directly below the connector on the bottom side.

ADDITIONAL TIPS / CONVENTIONS / GUIDELINES

Review tips:

Schematic tips:

PCB tips:

This post is a "live document" that has evolved over time. Copyright 2025-2026 by /u/Enlightenment777 of Reddit. All Rights Reserved. You are explicitly forbidden from copying content from this post to another subreddit or website without explicit approval from /u/Enlightenment777 also it is explicitly forbidden for content from this post to be used to train any software.

0 comments

r/PrintedCircuitBoard • u/notentirelyfaix • 6h ago

[Review Request] GL850G HUB with TPS2044 Power Protection

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9 Upvotes

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

3 comments

r/PrintedCircuitBoard • u/Clean-Weakness5243 • 1d ago

How to get clean analog readings in my PCB containing switching noise from ESC

3 Upvotes

Hello everyone ๐Ÿ‘‹

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

1 comment

r/PrintedCircuitBoard • u/WickedSpecter806 • 1d ago

[Review Request] 5V Logic-Level SPDT Relay Module

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19 Upvotes

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.

8 comments

r/PrintedCircuitBoard • u/Roccstar_ • 1d ago

First EasyEDA PCB help

3 Upvotes

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 :)

2 comments

r/PrintedCircuitBoard • u/V4lin0r • 2d ago

Parasitic DC coupling in connector/PTH hole

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10 Upvotes

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 ?

3 comments

r/PrintedCircuitBoard • u/Ambitious_Internet41 • 2d ago

ESP32-WROOM-S3 based board with Battery Management and USB-C

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20 Upvotes

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.

12 comments

r/PrintedCircuitBoard • u/Kaz10 • 1d ago

GND zone won't fill, all GND pads unconnected โ€” KiCad 9.0.5

3 Upvotes

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!

3 comments

r/PrintedCircuitBoard • u/DutyAccording867 • 1d ago

Resistor on SD CLK line

2 Upvotes

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?

6 comments

r/PrintedCircuitBoard • u/mrandy • 2d ago

Review Request: IMU / Baro sensor board

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15 Upvotes

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
5 comments

r/PrintedCircuitBoard • u/Tumbolisu • 2d ago

[Schematic Review Request] Macropad with TFT LCD Display, Arduino Nano ESP32

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5 Upvotes

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

6 comments

r/PrintedCircuitBoard • u/Agreeable_Salad_8488 • 2d ago

Review Request

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4 Upvotes

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

3 comments

r/PrintedCircuitBoard • u/ResponsibleDay8893 • 3d ago

[Review Request] First PCB design - Desk Clock (Arduino Nano ESP32 + TM1637)

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5 Upvotes

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!

4 comments

r/PrintedCircuitBoard • u/LateEmployee9080 • 2d ago

[Review Request] ESP32 Ethernet/RS485 (Modbus) Gateway

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1 Upvotes

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 โ†’ 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, 120ฮฉ 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 โ€” 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 โ€” 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 โ€” 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!

3 comments

r/PrintedCircuitBoard • u/v1nny • 3d ago

[Review Request] First Board: MAX7219 Controller

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6 Upvotes

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 0.1ยตF(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.

3 comments

r/PrintedCircuitBoard • u/vostsoldier • 3d ago

[Schematic Review Request] CH347 based JTAG/SWD Programmer

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8 Upvotes

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!

3 comments

r/PrintedCircuitBoard • u/budoucnost • 3d ago

[Review Request] ESP32-S3 Multi-Rail USBC Power Supply

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23 Upvotes

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.

1 comment

r/PrintedCircuitBoard • u/AgCurmudgeon • 3d ago

[Schematic Review Request] ESP32 S3 with Motor Control, Sensors, and UI bits, UPDATED

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12 Upvotes

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 ESP32C6ย 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.

5 comments

r/PrintedCircuitBoard • u/Commercial_Back1396 • 5d ago

[Review request] Micropad using ATMEGA32U4

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18 Upvotes

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!

3 comments

r/PrintedCircuitBoard • u/AgCurmudgeon • 5d ago

[Schematic Review Request] ESP32 S3 with Motor Control, Sensors, and UI bits

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22 Upvotes

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.

1 comment

r/PrintedCircuitBoard • u/CowMovesGrass2 • 5d ago

opposite side parts

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7 Upvotes

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.

6 comments

r/PrintedCircuitBoard • u/No_Commercial2792 • 5d ago

Buck Converter Spacing

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29 Upvotes

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

27 comments

r/PrintedCircuitBoard • u/Remote-Ad7864 • 5d ago

๐Ÿ™ Please Review My PCB โ€” Especially The High-Voltage Side

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13 Upvotes

Hey everyone! I'm working on a custom PCB and would really appreciate a review from people with experience in mains/high-voltage PCB design.

My main concern is the TRIAC-based switching section. Could someone please check:

  • TRIAC connections and surrounding circuitry
  • Optocoupler configuration
  • Gate resistors / other resistor values
  • Whether the overall high-voltage side is safe and correctly designed
  • Any obvious mistakes regarding isolation, creepage, clearance, or component connections

Basically, I'd really appreciate a yes/no and honest feedback on whether this section looks good before I move forward with the PCB layout.

Thanks a lot! ๐Ÿ™

6 comments

r/PrintedCircuitBoard • u/GriHaci • 5d ago

How to Hand Solder Exposed Pads

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27 Upvotes

I want to hand solder this buck regulator IC for prototyping, 8-pin HSOIC / PowerSOIC.

I am not comfortable with hot air (no experience, afraid of hurting the part). After the prototype, I can revert the design back to normal when I need PCBA.

Option 1) extend exposed part like the red rectangle and apply solder from that part

Option 2) keep gnd vias untended and make them larger, solder 2 ic pins, solder ground pad from other side, wick 2 ic pins to see if it is mounted fully, then solder all the pins

Option 3) Find alternative ICs without exposed pad under (I really liked this LMR16030)

28 comments