STM32L071K8U6 - 32MHz Cortex-M0+ 64KB Flash Ultra-Low-Power MCU | STMicroelectronics
MPN: STM32L071K8U6 ✓ ActiveSTM32L071K8U6 Overview
An ultra-low-power microcontroller is a class of MCU designed to minimize average energy consumption rather than just peak performance. The STM32L0 access line combines the Arm Cortex-M0+ core with multiple low-power sleep and stop modes, so a battery-powered design can spend most of its life at microamp current and wake to full 32 MHz operation only when work is required. In the standard electronics hierarchy, an MCU such as this sits below the microprocessor class and above embedded controllers: it integrates CPU core, Flash, SRAM, ADC, timers, and communication peripherals on a single die.
Key features of the STM32L071K8U6 include a 32 MHz Cortex-M0+ core with a 64 KB Flash program memory and an SRAM of the same low-power access-line class, a 12-bit successive-approximation ADC, low-power sleep and stop modes for duty-cycled operation, and an extremely small 5 x 5 mm footprint that saves board area in wearables and sensor nodes. The exposed pad under the UFQFPN package provides a low-resistance thermal path, which matters when the device runs continuously at 32 MHz.
Technically, the part belongs to the STM32L071xx family, whose design centers on fast wake-up times and low current draw in every non-active mode. Because the Cortex-M0+ architecture is a compact 32-bit RISC core, the same firmware that handles simple control loops also supports moderate protocol stacks over the on-chip USART, SPI, and I2C peripherals. The 5 x 5 mm land pattern, with 0.5 mm pitch pads, is dense enough for compact modules but requires careful PCB layout planning and fine-pitch assembly capability.
Typical applications include battery-operated sensor nodes, water and gas meters, industrial IoT endpoint devices, portable health monitoring accessories, energy-harvesting monitors, and smart-home peripherals where the combination of small size, low standby current, and a 12-bit ADC is more valuable than raw processing power.
When designing around this MCU, follow the manufacturer's recommended decoupling network with a 100 nF ceramic capacitor on each supply rail close to the pins, use the exposed pad as a ground plane connection, and route the NRST pin with a short, low-capacitance path. Confirm flash endurance and write-cycle requirements for logging applications, and keep the supply rail within the specified voltage range during brownout transitions to avoid unintended resets.
This page consolidates manufacturer specifications, drop-in replacement options, and practical design guidance for engineers evaluating the STM32L071K8U6, going beyond what a distributor catalog listing or a bare datasheet link provides.
Drop-in alternatives for STM32L071K8U6 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with STM32L071K8U6 (same form factor and footprint) — differing in Package, Flash Memory, Product Type, ADC Resolution, Architecture.
STM32L071K8T6
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
STM32L051K8T6
✅ Drop-In ⚠️ Specs UnverifiedContact for price
View Datasheet →STM32L071CZU6
✅ Drop-In ⚠️ Specs UnverifiedContact for price
View Datasheet →STM32L071KZ6U6
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
STM8L152K6U6
✅ Drop-In ⚠️ Specs UnverifiedContact for price
View Datasheet →STM32L071K8U6 Maximum Ratings & Electrical Characteristics
| Core | Arm Cortex-M0+ 32-bit RISC |
| Maximum CPU Frequency | 32 MHz |
| Flash Memory | 64 KB (64K x 8) |
| Package | 32-pin UFQFPN (5 x 5 mm) |
| ADC Resolution | 12 bit |
| Supply Voltage | 2.5 V / 3.3 V |
| Operating Temperature | -40 °C to +85 °C |
| Core Family | STM32L0 access line |
| Low-Power Modes | Sleep and stop low-power modes |
| Mounting Type | Surface Mount |
| Exposed Pad | Yes, thermal/ground pad |
| Shipping Format | Tray |
| Automotive Grade (AEC-Q100) | Not applicable (industrial/consumer access line) |
STM32L071K8U6 Pin Configuration
| Pin 1 | VBAT — Backup supply input |
| Pin 2 | PC14-OSC32_IN — General-purpose I/O or external 32.768 kHz oscillator input |
| Pin 3 | PC15-OSC32_OUT — General-purpose I/O or external 32.768 kHz oscillator output |
| Pin 4 | NRST — Active-low system reset input |
| Pin 5 | VSSA — Analog ground / VREF- connection |
| Pin 6 | VDDA — Analog supply / VREF+ connection |
| Pin 7 | PA0 — General-purpose I/O, ADC input, wake-up capable |
| Pin 8 | PA1 — General-purpose I/O, ADC input |
| Pin 9 | PA2 — General-purpose I/O, ADC input |
| Pin 10 | PA3 — General-purpose I/O, ADC input |
| Pin 11 | PA4 — General-purpose I/O, ADC input |
| Pin 12 | PA5 — General-purpose I/O, ADC input |
| Pin 13 | PA6 — General-purpose I/O, ADC input |
| Pin 14 | PA7 — General-purpose I/O, ADC input |
| Pin 15 | PB0 — General-purpose I/O, ADC input |
| Pin 16 | PB1 — General-purpose I/O, ADC input |
| Pin 17 | VSS — Digital ground |
| Pin 18 | VDD — Digital supply input |
| Pin 19 | PA9 — General-purpose I/O / USART or timer alternate function |
| Pin 20 | PA10 — General-purpose I/O / USART or timer alternate function |
| Pin 21 | PA11 — General-purpose I/O / USB or timer alternate function |
| Pin 22 | PA12 — General-purpose I/O / USB or SPI alternate function |
| Pin 23 | PA13 — SWDIO debug and programming data line |
| Pin 24 | PA14 — SWCLK debug and programming clock line |
| Pin 25 | PA15 — General-purpose I/O, timer or SPI alternate function |
| Pin 26 | PB3 — General-purpose I/O / timer or SPI alternate function |
| Pin 27 | PB4 — General-purpose I/O / timer or SPI alternate function |
| Pin 28 | PB5 — General-purpose I/O / timer or SPI alternate function |
| Pin 29 | PB6 — General-purpose I/O / I2C or USART alternate function |
| Pin 30 | PB7 — General-purpose I/O / I2C or USART alternate function |
| Pin 31 | VSS — Digital ground |
| Pin 32 | VDD — Digital supply input |
Typical Applications
STM32L071K8U6 is suitable for 6 applications: Battery-Powered Wireless Sensor Nodes, Smart Water and Gas Metering, Industrial IoT Endpoints and Condition Monitoring, Portable Health and Wellness Wearables, Smart Home and Building Peripheral Nodes, Energy Metering and Power Monitoring.
Battery-Powered Wireless Sensor Nodes
The STM32L071K8U6 suits compact wireless sensor nodes because the 32 MHz Arm Cortex-M0+ core handles low-rate radio control and sensor polling while the ultra-low-power sleep and stop modes keep average consumption low. Its 64 KB of Flash is ample for a protocol stack plus application logic, and the 12-bit ADC digitizes resistive, thermistor, or ratiometric sensors directly. Placing the device in a 5 x 5 mm UFQFPN package frees board area for the radio and battery in a wearable or remote-monitoring form factor. Note that the part is intended for 2.5 V or 3.3 V rails, so a cell plus low-dropout regulator topology should be sized accordingly.
Recommended
Smart Water and Gas Metering
Utility meters benefit from the STM32L071K8U6's combination of a 12-bit ADC and long-lived low-power operation, since a slow-moving flow or pressure sensor only needs periodic sampling. The Cortex-M0+ core is sufficient for pulse counting, tamper detection, and periodic wireless reporting, while the -40 °C to +85 °C range covers typical meter enclosure temperatures. The 32-pin UFQFPN 5 x 5 mm footprint allows the meter board to fit behind a small display and battery compartment. Firmware can be sized against the 64 KB Flash budget; for larger protocol or data-buffer needs, the same footprint family offers higher Flash-density options.
Recommended
Industrial IoT Endpoints and Condition Monitoring
Condition-monitoring endpoints use the STM32L071K8U6 to sample vibration or temperature sensors and report anomalies over a serial or wireless link. The 12-bit ADC with the low-power mode set lets the device run for years on a primary cell, while the 32 MHz Cortex-M0+ core handles filtering and threshold logic that would otherwise need a larger MCU. Its small UFQFPN land pattern suits retrofits into tight DIN-rail or equipment-mounted enclosures. For designs needing more GPIO or faster sampling, the same STM32L0 family in the same 32-pin outline offers higher-density variants, so PCB layout work is reused across the platform.
Recommended
Portable Health and Wellness Wearables
In wearable wellness devices, the STM32L071K8U6 provides enough processing for activity tracking and gesture sensing while keeping board area under a few square centimeters. Its 12-bit ADC supports direct front-end interfacing to optical or resistive sensor channels, and the low-power stop mode allows a wrist device to run for weeks between charges. The 5 x 5 mm package also keeps the design compatible with the small form factors demanded by wearables, and the 2.5 V and 3.3 V supply options simplify matching to coin-cell and lithium-polymer regulators. Compliance with the -40 °C to +85 °C range covers most consumer and clinical-room environments.
Recommended
Smart Home and Building Peripheral Nodes
Smart-home peripherals such as occupancy sensors, light controls, and thermostats typically need a low-cost microcontroller that can sit on a low-power rail and wake on demand. The STM32L071K8U6 handles the on/off logic, timer-based scheduling, and serial connectivity in a 32-pin 5 x 5 mm package, while its sleep and stop modes limit standby draw in a wall-switch or sensor form factor. The Cortex-M0+ ecosystem also keeps the software toolchain simple. Where a mains-adjacent design requires reinforced isolation on the communication side, add an appropriate isolated transceiver rather than relying on the MCU's own I/O protection.
Recommended
Energy Metering and Power Monitoring
The STM32L071K8U6 is appropriate for power-monitoring modules that measure current and voltage through a resistive divider and shunt. Its 12-bit ADC resolves the sensed waveform samples, and the Cortex-M0+ core can run the calculation, calibration, and reporting task, while low-power modes reduce consumption between measurement windows. The 32-pin UFQFPN package keeps the sensing board compact enough to fit behind a DIN rail meter front panel, and the -40 °C to +85 °C rating covers the thermal environment inside most meters. For three-phase designs that need simultaneous sampling, pair it with an external multi-channel ADC such as an MCP3428.
Recommended
Recommended Products Summary
Engineering reference data for STM32L071K8U6 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | STM32L071K8T6 | STM32L051K8T6 | STM32L071CZU6 | STM32L071KZ6U6 | STM8L152K6U6 |
|---|---|---|---|---|---|---|
| Package | 32-pin UFQFPN (5 x 5 mm) | 32-pin UFQFPN (5 x 5 mm) - same | 32-pin UFQFPN (5 x 5 mm) - same | 32-pin UFQFPN (5 x 5 mm) - same | 32-pin UFQFPN (5 x 5 mm) - same | 32-pin UFQFPN (5 x 5 mm) - same |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics |
| CPU Core | Arm Cortex-M0+ 32-bit | Arm Cortex-M0+ 32-bit | Arm Cortex-M0+ 32-bit | Arm Cortex-M0+ 32-bit | Arm Cortex-M0+ 32-bit | 8-bit STM8 core (different register map) |
| Maximum Frequency | 32 MHz | 32 MHz | 32 MHz | 32 MHz | 32 MHz | 32 MHz |
| Flash Memory | 64 KB (64K x 8) | 64 KB (64K x 8) | 64 KB (64K x 8) | 128 KB (+100%) | 256 KB (+300%) | 64 KB |
| ADC Resolution | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit |
| Operating Temperature | -40 °C to +85 °C | -40 °C to +105 °C | -40 °C to +105 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C |
| Supply Voltage | 2.5 V / 3.3 V | 2.5 V / 3.3 V | 2.5 V / 3.3 V | 2.5 V / 3.3 V | 2.5 V / 3.3 V | 2.5 V / 3.3 V |
| Low-Power Positioning | Ultra-low-power STM32L0 access line | Ultra-low-power STM32L0 access line | Ultra-low-power STM32L0 access line | Ultra-low-power STM32L0 access line | Ultra-low-power STM32L0 access line | Ultra-low-power STM8L line |
| Firmware Portability | Cortex-M0+ toolchain, STM32L0 peripheral set | Identical, same die | Cortex-M0+ toolchain, minor peripheral differences | Identical core, larger memory map | Identical core, larger memory map | Requires firmware rewrite (8-bit core) |
Key Differentiators
- Same-package second source without code changes (vs STM32L071K8T6)
- Full 64 KB of Flash in the smallest footprint of the family options (vs STM32L071KZ6U6)
- 12-bit ADC and Cortex-M0+ in a 5 x 5 mm package for analog sensing (vs STM8L152K6U6)
- Cost-optimized 32 MHz MCU with the same pinout as higher-Flash siblings (vs STM32L071CZU6)
Design Notes
The 32-pin UFQFPN uses 0.5 mm pitch pads on a 5 x 5 mm body, so a designed land pattern with 0.5 mm pitch and 0.3 mm pad width is required for reliable paste printing and reflow. Place the exposed pad as a thermal and ground connection with a dense via array into the internal ground plane; do not treat the pad as optional, because it carries both heat and the return path for the supply reference. Validate the assembly process early, since fine-pitch QFN parts are sensitive to placement alignment and solder-paste volume.
Apply a 100 nF ceramic decoupling capacitor at every supply pin, placed on the same board side and as close to the pad as the layout rules allow, and add 1 uF to 4.7 uF of bulk capacitance near the supply entry point. Estimated budget for a duty-cycled sensor node: with a 3.3 V rail, a 10 uA average current and 2000 hours of operation, the battery must supply roughly 66 mAh, so quiescent current in the dominant sleep state dominates run time. Confirm the actual sleep-mode current figure in the manufacturer datasheet for your chosen clock configuration.
Keep the SWD debug interface (PA13 SWDIO and PA14 SWCLK) accessible and route it away from noisy switching nodes, because an unpopulated or difficult-to-access debug port delays production bring-up. Maintain a short, low-capacitance NRST trace with a pull-up network placed close to the pin, and avoid routing any high-current or switching return path beneath the analog supply pins VSSA and VDDA. Separate the analog ground reference path from digital return currents so the 12-bit ADC retains useful accuracy at low signal levels.
Two frequent mistakes are underestimating the Flash budget and ignoring brownout behaviour. Firmware with a bootloader, a protocol stack and OTA update handling can exceed 64 KB, so measure the linked image size before committing to the K8U6 and consider a 128 KB variant in the same footprint if the margin is thin. Second, ensure the supply rail stays inside the specified 2.5 V and 3.3 V operating range during input transients; a supply dip that falls below the brownout threshold causes resets that look like firmware faults during field testing.
Compliance Information
The STM32L071K8U6 is an industrial/consumer access-line part and is not AEC-Q100 qualified; RoHS, REACH, lead-free and halogen-free statements were not present in the manufacturer or distributor listings reviewed, so they are reported as unknown rather than assumed.