EFR32BG22 vs WBZ451

EFR32BG22 vs WBZ451: Silicon Labs vs Microchip BLE SoC Comparison

Overview

The EFR32BG22 from Silicon Labs and the WBZ451 from Microchip Technology represent two distinct philosophies for a low-cost, BLE-capable wireless SoC. The EFR32BG22 is positioned as a premium-tier, security-focused BLE SoC with Secure Vault and excellent power optimization. The WBZ451 is Microchip's entry into the multiprotocol wireless SoC space, designed to bring BLE and Zigbee connectivity to the large base of PIC and AVR embedded developers who are already familiar with Microchip's MPLAB X ecosystem.

The EFR32BG22 uses an ARM Cortex-M33 running up to 38.4 MHz, supports BLE 5.2, and is available in a compact 4×4 mm QFN32 package. Its 352 KB Flash is oriented toward sensor and peripheral profiles. Silicon Labs' Simplicity Studio provides a well-documented SDK with pre-built Bluetooth SIG profiles, reference applications, and network analyzer tools.

The WBZ451 is also based on an ARM Cortex-M4F (with FPU) running up to 64 MHz, offering notably higher compute performance than the BG22's M33 at 38 MHz. It integrates 1 MB of Flash and 128 KB of RAM, supporting both BLE 5.2 and Zigbee 3.0. Microchip's MPLAB Harmony 3 framework and its familiar MPLAB X IDE lower the learning curve for PIC/AVR developers. The WBZ451 is priced aggressively, making it attractive for cost-sensitive production volumes in home automation, lighting, and appliance control.

Key Differences

• CPU: EFR32BG22 uses Cortex-M33 at 38.4 MHz; WBZ451 uses Cortex-M4F at 64 MHz — WBZ451 has significantly higher compute throughput and an FPU.
• Memory: BG22 has 352 KB Flash / 32 KB RAM; WBZ451 has 1 MB Flash / 128 KB RAM — WBZ451 offers substantially more storage for complex firmware.
• Protocols: WBZ451 supports BLE 5.2 and Zigbee 3.0 concurrently; EFR32BG22 is BLE-only.
• Security: EFR32BG22 includes Secure Vault Mid with hardware root of trust, PUF-based key storage, and device attestation; WBZ451 provides standard hardware AES but lacks equivalent key lifecycle management.
• Ecosystem: WBZ451 targets Microchip MPLAB X / Harmony 3 developers; EFR32BG22 uses Simplicity Studio / Gecko SDK.
• Power: EFR32BG22 achieves approximately 1.0 µA in deep sleep (EM2); WBZ451's deep sleep is in the 1–3 µA range — BG22 has a modest power advantage for coin-cell designs.
• Cost: WBZ451 is positioned at the lower end of the price spectrum; BG22 commands a premium for Secure Vault and package density.

Use Cases

EFR32BG22 is ideal for: - BLE-only applications requiring hardware security certification (medical, industrial) - Compact wearables and disposable patches where 4×4 mm package and coin-cell life are critical - High-volume designs where BLE profile simplicity enables minimal firmware footprint

WBZ451 is ideal for: - Smart home devices requiring Zigbee + BLE coexistence (Zigbee mesh with BLE provisioning) - Designs developed by teams with existing Microchip/PIC expertise seeking minimal toolchain transition - Cost-sensitive, high-volume IoT products where 1 MB Flash enables richer firmware without OTA bank constraints - Applications needing FPU performance for floating-point sensor fusion or control algorithms

Verdict

Choose the EFR32BG22 when security (Secure Vault), ultra-low sleep current, and compact packaging are the top requirements for a BLE-only application. Choose the WBZ451 when your team lives in the Microchip ecosystem, when Zigbee coexistence is needed, or when higher compute performance and more Flash are required at a lower price point.