SF32LB52x¶

Overview¶

SF32LB52x is SiFli's cost-optimized MCU family for entry-level smart wearables, compact graphical HMIs, Bluetooth peripherals, and other space-constrained AIoT products that still need integrated display, audio, storage, and wireless capability.

At the platform level, the family combines a 240MHz Arm Cortex-M33 STAR-MC1 application core with a dedicated 24MHz low-power Bluetooth controller core, enabling the chip to run a responsive UI and application stack while keeping Bluetooth connectivity and always-on workloads separate.

For product planning, the important distinction is that SF32LB52 is split into two supply-oriented subfamilies:

• SF32LB520/3/5/7: lithium-ion battery-powered variants with an integrated charger path
• SF32LB52B/D/E/G/J: external-supply variants, where 52B/E/G/J target standard 3.3V systems and 52D targets a special 1.8V ultra-low-power rail

These groups are not interchangeable at the board level. The battery-powered and external-supply families are not pin compatible with each other, and the 1.8V 52D variant is also electrically distinct from the 3.3V 52B/E/G/J group even where package alignment looks similar.

Applications¶

SF32LB52x is recommended for Bluetooth-centric products where cost, integration, and battery life are the primary design considerations, including:

• Entry-level smartwatches and fitness bands
• Bluetooth modules and wireless adapters
• Bluetooth audio accessories
• Smart sensors and wearable devices
• Electronic shelf labels and smart badges
• Portable label printers
• eBike and eScooter displays
• Basic LVGL-based HMI devices

Development Resources¶

Features and Specs¶

Compute and Memory¶

• Arm Cortex-M33 STAR-MC1 application core up to 240MHz, with DSP and MPU
• Dedicated Arm Cortex-M33 STAR-MC1 Bluetooth controller core at 24MHz
• 32 KB instruction cache + 16 KB data cache
• 512 KB application SRAM plus 64 KB Bluetooth-controller SRAM
• Variant-dependent co-packaged memory options ranging from 1MB QSPI-NOR to 16MB OPI-PSRAM

Graphics and Audio¶

• ePicasso 2.0 Lite 2D/2.5D graphics accelerator
• eZip 2.0 hardware decoder for lossless graphics compression
• Dedicated LCD controller supporting SPI/DSPI/QSPI, including e-paper SPI, plus 8080-8bit
• 1x 24-bit Audio ADC with 109 dB SNR
• 1x 24-bit Audio DAC with 99 dB SNR

Wireless Connectivity¶

• Dual-mode BT/BLE, BT6.3 certified
• Maximum transmit power:
  • 17 dBm for BLE and BT/BR
  • 13 dBm for BT/EDR2 and BT/EDR3
• Sensitivity: -100 dBm @ BLE/1Mbps
• Dedicated Arm Cortex-M33 STAR-MC1 Bluetooth-controller core with 64 KB SRAM @ 24MHz
• Ultra-low sleep current around 2 µA for always-on wearable designs

Security¶

• AES/HASH/CRC hardware accelerators
• TRNG
• PSA Level 1 Certified

Peripherals and I/Os¶

• 3x UART
• 4x I2C
• 2x SPI
• 1x USB2.0 FS
• 1x I2S
• 1x PDM
• 1x SD3.0/SDIO3.0/eMMC
• 1x 12-bit general-purpose ADC
• Temperature sensor
• RTC and watchdog timers
• 44 or 45 GPIOs depending on variant family

Power Supply¶

• Battery-powered group: SF32LB520/3/5/7 — powered directly from a single-cell Li-ion/Li-Po battery and intended for designs that use the integrated charging-oriented power architecture.

• External-supply 3.3V group: SF32LB52B/E/G/J — intended for regulated external-supply systems and pin compatible with one another.

• External-supply 1.8V group: SF32LB52D — intended for special ultra-low-power 1.8V designs and not electrically interchangeable with the 3.3V parts.

The battery-powered and external-supply groups are independent silicon configurations and are not pin compatible across those supply families.

Family Variants¶

The practical part-selection split is:

• SF32LB520/3/5/7: lithium-ion battery-powered group, pin compatible within the group
• SF32LB52B/E/G/J: standard 3.3V external-supply group, pin compatible within the group
• SF32LB52D: special 1.8V external-supply variant for ultra-low-power scenarios

If you are migrating between memory tiers, the nearest content-correspondence map is:

• 520 ↔ 52B
• 523 ↔ 52E, with 52D as the 1.8V counterpart
• 525 ↔ 52G
• 527 ↔ 52J

Integration Path¶

Use this sequence to turn an SF32LB52x shortlist into a validated design:

1. Prove the firmware path. Start with the SiFli SDK getting-started guide, then use the SiFli SDK workflow and examples to validate the required peripherals and Bluetooth behavior.
2. Choose the integration vehicle. Evaluate SF32LB52-MOD-1 when a ready-integrated RF module suits the product; otherwise select the closest SF32LB52 development board for early firmware and peripheral validation.
3. Design and review the hardware. Use the local hardware design guide and hardware design checklist before releasing the schematic or layout. Confirm the correct supply-family baseline: 520/3/5/7, 52B/E/G/J, or 52D.
4. Verify the authoritative source. Check the applicable datasheet and SiFli [hardware design guide for 520/3/5/7] or [hardware design guide for 52B/D/E/G/J] against the exact orderable part and package.

Related Products¶

Module¶

SF32LB52-MOD-1 packages the SF32LB525UC6 chip, its RF matching network, and 8MB in-package OPI-PSRAM in the standard configuration, creating a certified, ready-to-integrate 27.9 × 18.0 × 3.1mm module for projects that want SF32LB52-class capability without owning chip-level RF layout and certification.

Development Kits¶

• SF32LB52-DevKit-LCD is the main display-oriented bring-up board for the SF32LB52 module ecosystem, with QSPI and MCU/8080 LCD connectivity.
• SF32LB52-DevKit-Core-3p3 is the compact external-supply core board for quick firmware, GPIO, and low-power bring-up on 52B/J-class parts.
• SF32LB52-DevKit-Nano is the smallest 52-series dev board, useful when the target product is size constrained.
• SF32LB52-DevKit-ULP is the low-power-oriented board path for battery-focused evaluation and compact product experiments.

Reference Products¶

Typical SF32LB52 designs include entry-level smartwatches, fitness bands, Bluetooth accessories, compact graphical controls, electronic shelf labels, smart badges, portable label printers, and cost-sensitive eBike or eScooter displays.