Prototyping vs. Production-Ready Electrical Engineering

Let's break it down with a case study: a wearable AI pendant built around the ESP32-S3. It packs a microphone array, a LiPo battery with USB-C power, and a PCB antenna into a compact, power-efficient design. How would a design intended for a few prototypes differ from one built for mass production? More importantly, how can a designer transition from one to the other?

System Architecture: Modular Prototyping vs. Integrated Design

A design for prototyping is likely to start with an ESP32 development board, stacking breakout modules for power, audio, and sensors, and wiring everything together on a protoboard. This modular approach speeds up development, allowing rapid iteration and debugging. However, the result is often bulkier and less optimized for power efficiency and performance.

• Uses off-the-shelf breakout boards for rapid prototyping.
• Trades compactness and efficiency for ease of modification and debugging.

A production-ready design follows a different path. It begins with a block diagram, mapping out power distribution, signal paths, and communication protocols. Instead of separate breakout boards, all functions are integrated into a single custom PCB. This minimizes component count, optimizes trace routing, and ensures better signal integrity, ultimately leading to a leaner, more reliable system.

• Custom PCB design consolidates components for better power efficiency.
• Optimized signal paths reduce EMI and improve overall system stability.

How to Transition: To move from a prototype to a production-ready design, start by identifying frequently used breakout board components and replace them with equivalent ICs that can be integrated directly onto the PCB. Use search tools like Digikey’s filter or Copilot to narrow the search and check the reference design or application note in each datasheet you are evaluating. Use the prototype to refine the design before committing to a custom layout.

Power Management: Simplicity vs. Efficiency

A prototype design might use an AMS1117 linear regulator because it’s easy to wire up and doesn’t require extra components. A generic charging module is typically added, setting up a functional but inefficient system that dissipates excess energy as heat.

• Simple and quick to implement but inefficient in power usage.
• Lacks control over charging parameters, potentially reducing battery lifespan.

A production-ready design optimizes every power stage. The MCP73832T charging IC is chosen with a charge current precisely set based on the battery’s capacity. A MOSFET-based power switch ensures seamless transitions between USB and battery power, while a carefully selected low-dropout regulator (LDO) or buck converter maximizes efficiency, extending battery life and reducing thermal issues.

• Implements precise power regulation to optimize efficiency and heat dissipation.
• Ensures safe charging and switching between power sources for longevity.

How to Transition: Instead of relying on modular solutions, select integrated power management ICs suited for your voltage and current requirements. Optimize power paths by minimizing unnecessary regulators and designing efficient layouts to reduce power loss.

RF Design: Plug-and-Play vs. Precision Engineering

A prototype design may rely on the ESP32’s built-in PCB antenna, which works for initial development but can suffer from signal degradation due to poor placement and interference.

• Uses pre-certified ESP32 modules for convenience but may suffer from interference.
• May not account for optimal PCB placement, leading to reduced wireless range.

A production-ready design requires careful RF planning. The ground plane is optimized, and impedance-controlled traces ensure signal integrity. A matching network is tuned to improve impedance matching, reducing signal reflection and maximizing transmission efficiency.

• Ensures impedance matching and optimal antenna placement for improved RF performance.
• Carefully routes traces to reduce signal loss and unwanted interference.

How to Transition: Follow manufacturer guidelines for PCB antenna placement and matching networks. There are many resources and simulation software's to ensure accurate design like Ansys. Use impedance-controlled stack-ups in your PCB layout to ensure signal stability and range.

Audio Subsystem: Direct Connection vs. Signal Conditioning

A prototype might connect MEMS microphones directly to the ESP32-S3’s ADC, which works but is susceptible to noise. Single-ended connections can pick up unwanted interference, degrading signal quality.

• Directly connects microphones to the ADC for simplicity.
• May introduce noise and signal distortion due to lack of differential routing.

A production-ready design accounts for signal integrity. Differential microphone routing reduces noise, and DC-blocking capacitors are selected to fine-tune frequency response. Impedance-matched traces ensure reliable signal transmission, while an external ADC is used for higher fidelity audio.

• Uses differential routing to improve noise rejection and signal clarity.
• Carefully selects ADC components for optimal performance and power consumption.

How to Transition: If audio quality is a key requirement, incorporate differential microphone routing and external ADCs early in the design. Use simulation tools to validate signal integrity before committing to the layout. Always check the frequency response characteristics of the ADC and Microphone.

PCB Layout: Knowing When to Use AI Auto-Layout

PCB design benefits from automation, but knowing when and how to use AI Auto-Layout is key. A prototype design might rely on auto-routing for the entire board, allowing for quick prototyping and iteration. This speeds up development but may introduce unnecessary vias, tangled traces, and potential EMI issues.

• Uses AI auto-routing for full board layouts, enabling fast iteration.
• Optimizes for speed and convenience over signal integrity in early prototypes.

A production-ready design takes a hybrid approach. High-speed, sensitive signals, and power traces are manually routed to ensure signal integrity. Once these critical traces are placed, AI Auto-Layout handles the remaining connections, reducing design time while maintaining quality.

• Manually routes high-speed signals and power traces to optimize EMI performance.
• Uses AI Auto-Layout strategically to accelerate workflow without sacrificing design quality.

How to Transition: Start by routing critical signals manually, especially high-speed traces and power connections. Use AI Auto-Layout for non-critical traces, ensuring design efficiency without compromising quality.

The Takeaway: Shared Principles, Different Constraints

Prototyping and production-ready designs share the same fundamental principles: understanding tradeoffs, optimizing efficiency, and refining designs. A prototype prioritizes flexibility and quick iteration, while a production design optimizes for manufacturability, longevity, and performance.

Neither approach is inherently better; they serve different purposes. The best designers learn from both worlds. Those developing prototypes can incorporate creative design methodologies, while those working toward production can embrace the structured and precision of integrated design.

At the end of the day, electrical engineering isn’t about rigidly following a set of rules—it’s about making smart, defensible decisions based on the constraints at hand. Whether you're building a quick prototype or refining a production-ready device, the key is knowing the why behind every choice.

Want to see a full breakdown of this project? Check out the complete design walkthrough!