nRF52840 vs EFR32BG22

nRF52840 vs EFR32BG22: Nordic's BLE+Thread Flagship vs Silicon Labs' Secure Vault BLE 5.3 SoC

The nRF52840 and EFR32BG22 are two respected professional BLE SoCs that differentiate in complementary directions. Silicon Labs' EFR32BG22 uses a modern Cortex-M33 core with Secure Vault hardware security, achieving lower sleep current in a small 3×3 mm package. Nordic's nRF52840 offers significantly more RAM, USB, 802.15.4 multi-protocol support, and a larger community ecosystem.

Overview

nRF52840 (Nordic Semiconductor) — 64 MHz Arm Cortex-M4F, 1 MB Flash, 256 KB RAM, BLE 5.0 + 802.15.4, USB 2.0. The highest-volume professional BLE SoC, with an extensive Zephyr RTOS ecosystem and pre-certified module availability across all major regulatory zones.

EFR32BG22 (Silicon Labs) — 76.8 MHz Arm Cortex-M33, 512 KB Flash, 32 KB RAM, BLE 5.3 with all PHYs including Coded and 2M. Secure Vault Mid: a dedicated hardware security subsystem providing a Physically Unclonable Function (PUF) for key storage, immutable secure boot, runtime anti-tamper detection, and FIPS 140-2 Level 3-equivalent AES/ECC/SHA acceleration. Particularly favored in smart metering, door locks, and credential storage applications where certified hardware security justifies BOM cost.

Key Differences

• RAM: nRF52840 has 256 KB vs EFR32BG22's 32 KB — an 8× difference that fundamentally limits application complexity on the BG22 to simple BLE sensors and beacons. nRF52840 runs full Zephyr RTOS with BLE stack, sensor drivers, and OTA logic simultaneously within this RAM.
• Secure Vault: EFR32BG22's Secure Vault Mid provides hardware PUF-based key generation (keys never leave secure memory), immutable secure boot with key revocation, runtime active anti-tamper monitoring, and FIPS 140-2 Level 3-equivalent cryptography — beyond nRF52840's CryptoCell-310. For applications requiring certified key isolation, the BG22 eliminates a separate secure element IC.
• BLE version: EFR32BG22 supports BLE 5.3 including Advertising">Direction Finding (AoA/AoD), extended advertising, and Connection Subrating; nRF52840 supports BLE 5.0. For Direction Finding RTLS tags, the BG22 is ahead.
• Sleep current: EFR32BG22 achieves approximately 1.0 µA in EM2 deep sleep; nRF52840 approximately 1.5 µA — BG22 has a modest but measurable advantage for coin-cell designs.
• Flash: nRF52840 has 1 MB vs BG22's 512 KB — meaningful for applications with dual-bank OTA and large BLE plus application codebases.
• USB: nRF52840 has USB 2.0 FS; EFR32BG22 does not.
• 802.15.4: nRF52840 supports Thread and Zigbee; EFR32BG22 is BLE-only.
• Package size: EFR32BG22 is available in 3×3 mm QFN; nRF52840 is smallest in 7×7 mm (or via module). For size-constrained applications where 32 KB RAM is sufficient, BG22 fits tighter spaces.

Use Cases

When nRF52840 Excels

• Multi-protocol smart home sensors and gateways running BLE + Thread or Zigbee concurrently on one chip.
• Complex RTOS-based wearables where 256 KB RAM accommodates Zephyr, BLE stack, sensor fusion, display management, and OTA simultaneously.
• USB HID and CDC devices requiring wired plus wireless connectivity without an external USB-to-UART bridge.
• Designs where community ecosystem depth matters: Nordic's Zephyr contributions, open-source BLE profiles, and extensive online resources reduce development time.

When EFR32BG22 Excels

• Door locks and physical access control where Secure Vault's hardware key protection eliminates the need for an external secure element and provides verifiable anti-tamper resistance.
• Smart energy metering where FIPS 140-2 Level 3-equivalent cryptography is a regulatory requirement for metering key storage.
• BLE 5.3 Direction Finding RTLS tags in tiny 3×3 mm packages where 32 KB RAM is sufficient for simple tag firmware.
• Medical credential storage devices requiring certified cryptographic hardware isolation without dual-core complexity.

Verdict

The EFR32BG22 makes its strongest case when Secure Vault certified hardware security is a design requirement — it removes the need for an external secure element and provides FIPS-equivalent key isolation. The nRF52840 wins decisively on RAM (8×), USB, 802.15.4, Flash, and ecosystem maturity. For any application needing RTOS complexity, multi-protocol networking, or USB, the nRF52840's memory headroom is non-negotiable. For security-critical BLE-only sensors and access control devices in small packages, the EFR32BG22 is a compelling specialist choice.