C8051F921-G-GM

Overview

The C8051F921-G-GM is a mixed-signal microcontroller from the Silicon Labs C8051F92x series, featuring a high-speed 8051 core operating at up to 25 MHz. It integrates 32 kB of in-system programmable Flash memory and 4352 bytes of internal data RAM. The device supports a supply voltage range of 0.9 V to 3.6 V, accommodating single-cell (0.9–1.8 V) and dual-cell (1.8–3.6 V) battery applications through an integrated DC-DC converter and LDO regulator. Key analog peripherals include a 10-bit SAR ADC with up to 300 ksps throughput, two comparators, and a built-in temperature sensor. Digital interfaces comprise hardware SMBus, dual SPI ports, and a UART.

Feature Summary

• Integrated DC-DC converter enables efficient operation in single-cell battery modes down to 0.9 V.
• High-speed pipelined 8051 core delivers up to 25 MIPS throughput at 25 MHz clock speeds.
• On-chip debug circuitry facilitates full-speed, non-intrusive in-system debugging without external emulators.
• Flexible clocking architecture includes precision internal oscillators and a low-power SmaRTClock for real-time functions.

Applications

• Battery-powered portable medical equipment
• Industrial control systems requiring low-voltage operation
• Smart metering and utility monitoring devices
• Wireless sensor nodes and IoT endpoints

Procurement Notes

Verify that the specific suffix matches the required package and temperature grade. Confirm the part status as this series may be designated Not Recommended for New Designs. Ensure compatibility with existing firmware due to potential architectural differences in newer silicon generations. Check for any recent Product Change Notices regarding assembly or labeling updates before finalizing procurement orders.

Selection Notes

Select this component when system design requires robust analog performance alongside a mature 8051 instruction set. The integrated DC-DC converter makes it suitable for applications demanding extended battery life from single-cell sources. Consider the available I/O count and peripheral set against project requirements. Evaluate the trade-off between the legacy 8051 core and modern alternatives if new development is planned.

Part Context

This MCU belongs to the C8051F9xx family, which emphasizes ultra-low power consumption and high integration. The F92x variant specifically offers 32 kB of Flash, distinguishing it from the 64 kB F93x counterpart. The series is characterized by its ability to operate across a wide voltage range, making it distinct from standard 3.3 V or 5 V only microcontrollers in the broader embedded market.

Replacement Considerations

Silicon Labs recommends EFM8BB31F64G-QFN32 as a replacement for this part number. Verify pinout compatibility and software migration efforts when transitioning to the EFM8 Busy Bee series.