Cherry Blossom vs Proteus: the best Proteus alternative for PCB design

Proteus Design Suite from Labcenter Electronics combines schematic capture, simulation and PCB layout. Its defining feature is VSM, Virtual System Modelling: you load firmware onto a supported microcontroller on the schematic and co-simulate it inside a mixed-mode SPICE simulation, peripherals included. Labcenter says its PCB products all include an autorouter and basic mixed-mode SPICE simulation. Its education page describes use in schools, colleges and universities, and recent releases added HDI micro-via support and AI-assisted part creation, according to Labcenter's homepage.

Cherry Blossom focuses on getting the board made. You describe the board; an agent writes it as tscircuit code in a cloud sandbox, builds it, and shows the schematic, PCB layout, 3D view and BOM. Footprints come from real part data and a verification gate checks every edit against manufacturing rules. It does not simulate circuits or firmware.

Labcenter sells Proteus in bundles: Enterprise for commercial PCB design, Platinum with everything it sells, or a custom package where you pick the modules. Its pricing page highlights perpetual licensing and links to a configurator and a full commercial price list. The prices did not display in a form we could quote, so check there. There is a demo version, time-limited only in simulation, and separate education pricing.

Pro is $20 a month with 4M AI credits and 600 AI actions a day. Ultra is $140 a month with 32M credits and the frontier models. Usage past the allowance is $5 per 1M credits, only if you turn it on. The AI is included, with no API key and no per-seat licence. See the pricing page.

This is that setup on a circuit that was already known: a load cell front end with an INA333 amplifier and an ADS1232 24-bit ADC, feeding a 7-pin header for whatever microcontroller reads it. An AI agent built it with tscircuit, the open-source engine Cherry Blossom runs on, using the same tscircuit version and the same review tool Cherry Blossom's agent uses, on our own machine. Full routed builds took 44 to 140 seconds. The board has not been fabricated or tested.

The layout work was the kind a Proteus user does by hand. Over three scored rounds the score went from 78 to 84 to 86 out of 100. The agent moved decoupling capacitors to about 2 mm from their pins, put the single 0 Ω tie between analog and digital ground where the 5 V line crosses the split, cut the board from 58 x 34 mm to 58 x 28 mm, and added an ESD diode on the excitation line. An outside review of the circuit then scored it 75, and 87 once six parts were added: a reverse-polarity MOSFET and five test points. The agent placed them without moving any existing part, and the redone layout scored 86. The final build had 0 build errors and 0 DRC errors, and the schematic review found 0 problems on either sheet.

Some things were left for a person. The 5 V line still crosses the ground split, right next to the tie. The review caught that swapped 5 V wires would have put a negative voltage on the regulator's input, which every automatic check had passed; the MOSFET now blocks it, but whether the host header needs ESD parts is still a person's call. The screw terminal's pads and the hand-drawn MOSFET pads were never checked against the makers' drawings. And nothing here runs the firmware that reads the ADC, including the power-down (PDWN) pin toggle the ADS1232 datasheet asks for at power-up. Checking code against the circuit is still what Proteus VSM is for.

• You need to run microcontroller firmware against the circuit before building it.

• You teach embedded systems and want students to debug without hardware.

• You want SPICE simulation and PCB layout in one licence you own outright.