Roles they hire for
- Wireless stack engineer (Zigbee, Thread, Matter, BLE)
- Low-power IoT firmware engineer
What they emphasise
- Zigbee, Thread, Matter and BLE SoCs
- Ultra-low-power IoT
- Hardware security
Brush up on
MatterThreadEnergy profilingEM2 and EM4 sleep modesSecure boot
How the rounds usually run
A typical silicon vendor loop for embedded roles. Companies vary by team and seniority.
Online assessment or screen
- C output prediction, pointers and bit manipulation
- Digital logic and OS basics
- For experienced hires, often a recruiter and hiring-manager screen instead
Example: What does this print: an unsigned char set to 200 plus 100, printed as an integer?
Technical 1: C and embedded fundamentals
- Pointers, volatile, const, alignment and endianness
- Interrupts, stacks and memory layout
- Live C coding on bit fields, ring buffers or string handling
Example: Implement a lock-free single-producer, single-consumer ring buffer.
Technical 2: Drivers and architecture
- Designing a peripheral driver and its API
- DMA, caches and interrupt priorities
- RTOS internals and debugging stories
Example: Design a SPI driver that supports blocking, interrupt and DMA modes behind one API.
Technical 3 or hiring manager: system design and projects
- Deep dive into a past project and your design choices
- System-level trade-offs: power, memory, performance
- Sometimes a short presentation on a project
Example: Walk through the hardest bug you've fixed, and what you changed in the process afterwards.
HR and behavioural
- Motivation, teamwork and conflict
- Relocation, notice period and compensation
Example: Tell me about a time you disagreed with a design decision.
Practice questions
Original questions written for Silicon Labs's focus areas, not leaked ones.
- Explain how a Matter device joins a network, step by step.
- A sleepy end device misses messages. How do polling and parent buffering interact?
- Design a power budget for a battery door sensor that reports every hour.
- How do you secure firmware updates across a mesh network?
- What makes Thread routing different from a star network?
Your prep playlist
Design rounds to practise
Themes are inferred from Silicon Labs's public product lines.
Take an AI mock round styled on Silicon Labs, with follow-ups that probe what you missed.
Start a mock round