STMicroelectronics STM8L151G3U3

Overview

STM8L151G3U3 from STMicroelectronics is an 8-bit ultra-low-power microcontroller featuring 8 KB Flash, 256-byte data EEPROM with ECC, RTC with ±0.5 ppm digital calibration, 12-bit ADC (1 Msps, 28 channels), two ultra-low-power comparators, and up to 41 I/Os in a 28-pin UFQFPN package. It operates from 1.65–3.6 V across –40 to +85 °C and targets battery-powered sensor nodes and portable medical devices requiring sub-μA Halt-mode current.

For engineers reviewing the STM8L151G3U3 datasheet, STM8L151G3U3 pinout, STM8L151G3U3 application, or STM8L151G3U3 equivalent, key selection criteria include verified Halt-mode current (300 nA typical), RTC accuracy under LSE clocking, capacitive touch channel count (up to 20), SWIM debug interface compatibility, and BOR threshold programmability across five levels.

Technical Context

The STM8L151G3U3 implements a Harvard-architecture STM8 core with 3-stage pipeline, delivering 16 CISC MIPS at 16 MHz. Its power management includes five distinct low-power modes-Wait, Low-power Run, Low-power Wait, Active-halt with RTC, and Halt-with 5 µs wakeup from Halt and 50 nA I/O leakage per pin.

Clock architecture integrates dual crystal oscillators (32 kHz LSE, 1–16 MHz HSE), factory-trimmed 16 MHz RC, and 38 kHz low-consumption RC, all protected by a clock security system. The RTC supports BCD calendar, alarm interrupt, auto-wakeup, and LSE security monitoring.

Key Specifications

Pinout & Package

STM8L151G3U3 is housed in a 28-pin UFQFPN (4 × 4 mm, 0.5 mm pitch) package with exposed thermal pad. This compact, lead-free, ECOPACK-compliant package supports high-density PCB layouts and efficient thermal dissipation in space-constrained designs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-low-power 8-bit microcontroller applications.

Compared with STM8L051F3P6, the STM8L151G3U3 adds RTC, EEPROM, and touch support at modest cost premium; versus STM32L011K4U6, it trades 32-bit compute headroom for superior analog integration and lower system-level BOM count in touch-and-sense applications.

Availability

STM8L151G3U3 is available at Aetrix Electronics and suitable for smart utility metering, portable medical sensors, industrial wireless sensor nodes, and home appliance control panels requiring stable component supply across extended product lifecycles.

Supply support for STM8L151G3U3 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, sensors, and analog products for industrial, automotive, and consumer markets.

The STM8L ultra-low-power MCU family targets battery-operated and energy-harvesting applications demanding sub-microamp sleep currents, integrated RTC, and rich analog peripherals-all within an 8-bit architecture optimized for deterministic real-time control.

FAQ

What is the minimum supply voltage for reliable operation with BOR enabled?

The STM8L151G3U3 requires a minimum supply voltage of 1.8 V when the Brown-out Reset (BOR) is enabled. BOR offers five selectable thresholds (1.65 V to 2.5 V), and operation below the selected threshold triggers a reset. At 1.8 V, all peripherals-including ADC, RTC, and comparators-function within datasheet specifications.

Does the device support capacitive touch sensing without external components?

Yes. The STM8L151G3U3 integrates a dedicated Capacitive Sensing Ground (CSG) peripheral supporting up to 20 channels. It uses charge-transfer measurement with built-in current sources and timing logic, enabling touchkey, proximity, linear, and rotary sensing without external resistors, op-amps, or dedicated touch ICs.

Can the RTC maintain accuracy when powered solely by a backup battery?

Yes. When VDD is absent, the RTC continues operating from the VBAT pin using an external coin-cell or supercapacitor. With LSE crystal (32.768 kHz) and digital calibration enabled, the RTC achieves ±0.5 ppm accuracy-equivalent to less than 16 seconds deviation per year-under stable temperature conditions.

Is SWIM debugging supported in all low-power modes?

SWIM debugging is fully functional in Run, Wait, and Low-power Run modes. In Low-power Wait, Active-halt, and Halt modes, SWIM remains accessible only if the debug session was initiated before entering the mode; it cannot wake the device from Halt. For production firmware, SWIM can be disabled via option bytes to prevent unauthorized access.