Errors marked. Circuits explained. All on your schematic.
Upload your netlist and schematic PDF. Our AI checks every part against its datasheet and returns your PDF with each issue marked on the drawing. No BOM needed.
SHEET 01 · THE PROBLEM
One missed pull-up. One missing ESD diode. One respin.
- Schematic
- Layout
- Fab + assembly
- Bring-up ✕
back to the schematic, and order the boards again
Everything explained, on one screen.
No more datasheet ping-pong
Stop switching between your schematic and datasheets. The datasheet check for every pin is written onto the drawing, next to the pin.
New schematic? Now it’s easy to read.
Complex circuits take hours to understand. Each block is explained on the drawing, so you don’t have to work through it line by line.
SHEET 02 · WHAT YOU GET
Errors we catch. Circuits we explain.
Red marks · errors that cause respins
- Voltage mismatches3.3 V LDO on a 3.0–4.2 V LiPo
- Pin misusebattery sense on ADC2, dead with Wi-Fi on
- Missing ESD & protectionno ESD on USB D+ / D−
- Missing pull-ups & terminationCC1/CC2 floating, no 5.1k Rd
- Insufficient decouplingno 100 nF at the sensor’s VDD
- Configuration errorsGPIO45 strap selects 1.8 V flash
Blue notes · what the circuit does
- What each pin doesU2 PROG sets the charge current
- Signal pathVBAT → R6/R7 divider → U1 ADC
- Key values, calculatedVBAT ÷ 2 · divider draws ≈ 21 µA
- Power treeUSB 5 V → U2 → LiPo → U3 → 3.3 V
SHEET 03 · LIVE DEMO
Try it now on a sample schematic
A sample board, already reviewed by our AI. Read the notes on the drawing, then ask the AI about any part.
USB 5 V input. Goes through C1 (4.7 µF) to the charger’s VDD.
A USB-C source turns on VBUS only after it sees a 5.1 kΩ pull-down (Rd) on CC.
Issue
CC1 and CC2 are floating. The board powers up on a USB-A-to-C cable, but a C-to-C charger or laptop port supplies nothing.
Add 5.1 kΩ from CC1 to GND and from CC2 to GND.
Source: USB Type-C spec, Sink Rd
Board ground.
Supply input, 3.75–6 V, so USB 5 V is in range. C1 (4.7 µF ceramic) meets the recommended input capacitor.
Source: MCP73831 datasheet
Charge status output: low while charging, high when done, high-Z with no battery.
Issue
Not connected. Charging still works, but nobody can tell charging from done.
Suggestion: LED + 470 Ω to VDD, or read it on a spare GPIO.
Source: MCP73831 datasheet, STAT output
Charge output to the cell: constant current, then constant voltage at 4.20 V. C2 (4.7 µF) meets the minimum output capacitance for stability.
Source: MCP73831 datasheet
The resistor from PROG to GND sets the charge current: I = 1000 V ÷ R_PROG.
Issue
R2 = 2.0 kΩ sets 500 mA. That charges the 200 mAh cell at 2.5C, while small LiPo cells are usually rated for 1C. Expect heat, faster wear and a safety risk.
Change R2 to 5.1 kΩ (≈196 mA, 1C) or 10 kΩ (100 mA, 0.5C).
Source: MCP73831 datasheet, charge current
Ground. Tie it to a wide copper pour; the charger sheds its heat here.
Fed straight from the LiPo cell (VBAT). C2 (4.7 µF) doubles as the 1 µF input capacitor if placed close.
Issue
To hold 3.3 V, VIN must stay above 3.3 V plus dropout (250 mV typ at 600 mA). A LiPo runs down to 3.0 V, so below about 3.5 V the rail sags and Wi-Fi bursts cause brownout resets. A large part of the battery goes unused.
Use a buck-boost regulator (e.g. TPS63001), or set brownout and low-battery cutoff near 3.5 V in firmware.
Source: AP2112 datasheet, dropout voltage
Tied to VIN, so the regulator is always on. VIN stays above the 1.5 V EN threshold.
+3V3 output. C3 (1 µF ceramic) meets the minimum output capacitance for stability.
Source: AP2112 datasheet
Ground.
The WROOM-1 module has the ESP32-S3, flash, crystal, Wi-Fi radio and PCB antenna built in, so only power and GPIOs appear on the schematic. 3.0–3.6 V supply. C6 (10 µF) and C7 (0.1 µF) meet Espressif’s 10 µF minimum; their module reference design uses 22 µF. The supply must deliver at least 500 mA; the AP2112K is rated for 600 mA (see U3 VIN).
Source: ESP32-S3-WROOM-1 datasheet; ESP32-S3 hardware design guidelines
Chip enable and reset. R3 (10 kΩ) pulls it up to 3V3.
Issue
No capacitor. Espressif recommends an RC delay (10 kΩ + 1 µF) so EN rises after the supply settles. Without it, the chip can fail to boot on a slow power-up.
Add 1 µF from EN to GND. A reset button can go here too.
Source: ESP32-S3 hardware design guidelines
Strapping pin. The internal pull-up boots from flash; hold SW1 during reset for download mode. Correct.
Strapping pin that sets the flash supply (VDD_SPI) at boot: low = 3.3 V, high = 1.8 V. An internal pull-down holds it low by default.
Issue
R4 pulls it high, so VDD_SPI starts at 1.8 V. The N8 module has 3.3 V flash, so it will not boot.
Remove R4 and let the internal pull-down hold GPIO45 low.
Source: ESP32-S3 datasheet, strapping pins
Native USB (Serial/JTAG), wired straight to J1. You can flash and debug over USB, and the pin choice is correct.
Issue
No ESD protection at the connector, where static discharge lands.
Suggestion: add a low-capacitance USB ESD array (USBLC6-2 class) next to J1.
Source: general ESD practice; ESP32-S3 hardware design guidelines, USB
I²C data to U4 (SHT40, address 0x44). R8 (4.7 kΩ) suits 100 and 400 kHz. Not a strapping pin.
I²C clock. R9 (4.7 kΩ) pull-up. Not a strapping pin.
Reads half of VBAT (2.1 V max) through the R6/R7 100k/100k divider, which draws about 21 µA all the time.
Issue
GPIO14 is an ADC2 channel, and the ESP32-S3 shares ADC2 with its Wi-Fi radio. While Wi-Fi is using it, battery reads can fail with a timeout. The radio and antenna are built into the WROOM-1 module, so they don’t appear on the schematic.
Move the divider to an ADC1 pin (GPIO1–10) and add 0.1 µF from that pin to GND. For low power, switch the divider with a MOSFET and enable it only to measure.
Source: ESP-IDF ADC driver docs; ESP32-S3 hardware design guidelines, ADC
Ground, including the module’s exposed pad.
I²C data, shares the R8 pull-up. Address 0x44 (SHT40-AD1B).
I²C clock, shares the R9 pull-up.
Supply, 1.08–3.6 V. +3V3 is in range.
Issue
No 100 nF decoupling capacitor at the sensor, which the datasheet recommends between VDD and VSS. It can add noise to readings and upset I²C.
Place 100 nF right at U4 pin 3.
Source: SHT4x datasheet
Ground.
I reviewed this sample board: an ESP32-S3 with USB-C charging, a LiPo charger, a 3.3 V LDO and an I²C humidity sensor. I checked all 25 IC pins against their datasheets. 16 are fine and 9 need a fix. Ask me about any of them.
SUGGESTED · FREE
SHEET 04 · HOW IT WORKS
How it works
-
01
Upload
Your netlist and schematic PDF. No BOM needed.
AltiumCadenceKiCadSiemensEagleEasyEDA -
02
Senior-level AI review
An AI trained for circuit review checks each part and net: datasheet limits, pin functions, required external parts and common design pitfalls.
-
03
In-Schematic Report
Findings and circuit explanations are written into your schematic, next to the parts they concern. See the circuit and every error on one screen.
SHEET 05 · UPLOAD
Get your free review
Your netlist, your schematic PDF and an email address. We check the files right away, ask about any part we can't identify, and email you the In-Schematic Report.
First board freeMost boards arrive within 24 hours. Your quote shows the estimate before you start.
SHEET 06 · SECURITY
Your designs stay yours
- Files deleted 12 months after your review, or sooner if you ask
- Your designs are never used to train AI models
- Encrypted in transit and at rest
- You own everything you upload
SHEET 07 · FAQ
Questions
Do I need a BOM?
No. We read part numbers from your netlist and schematic. If we can't identify a part, we ask you for its part number within minutes of upload. You can skip it, and that part is reviewed with estimated values.
Which tools are supported?
Siemens (Xpedition, DxDesigner, PADS Pro and PADS Logic), Cadence (OrCAD, HDL and Concept), Altium, KiCad, Eagle / Fusion Electronics and EasyEDA. Export a netlist and a schematic PDF from your tool; each tool has a short export guide. Using Zuken or something else? Upload your files anyway and we'll get back to you, or request it and we'll prioritise by demand.
How long does it take?
Most boards arrive within 24 hours. Your quote shows the estimate before you start. If we need a part number from you, we ask within a few minutes of upload.
Is it free?
Your first board is free, with no card needed. Reviews stay free until paid checkout opens. After that you pay per board; see Pricing.
What if you can't find a part?
We show you the parts we couldn't identify and ask for their part numbers. If you skip one, it is still reviewed, and the report marks it "Reviewed with estimated values".
How are my files protected?
Reviews are produced by AI. Files are encrypted, kept for 12 months after your review and then deleted (sooner if you ask), and never used to train AI models.
[Eyebrow — waiting for approval]
[Heading — waiting for approval]
[Found issue, one line — customer's words]
[Found issue, one line — customer's words]
[Found issue, one line — customer's words]
From customers who received a CircuitProver review, quoted with permission.
Send your schematic. Get it back red-penned.
Netlist and PDF in, annotated PDF out. Most boards arrive within 24 hours. No BOM needed.
Get your free review