STM32L151RCT6 - 32MHz Cortex-M3, 256KB Flash MCU | STMicroelectronics
MPN: STM32L151RCT6 β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.2 | $6.20 |
| 10 | $5.55 | $55.50 |
| 100 | $4.85 | $485.00 |
| 500 | $4.3 | $2,150.00 |
| 1,000 | $3.85 | $3,850.00 |
STM32L151RCT6 Overview
An ultra-low-power MCU is a microcontroller engineered to minimize energy per operation and standby consumption, sitting within the broader hierarchy of ARM Cortex-M-based microcontrollers under the power-management-optimized IC family. The STM32L1 series uses STMicroelectronics proprietary ultra-low-leakage process technology with autonomous dynamic voltage scaling, allowing the core to run from a scaled supply without external regulation complexity.
Key features include 256 KB Flash and 32 KB of ECC-enabled RAM, a 32 MHz Cortex-M3 core, USB FS device support, and 3x integrated op-amps that offload analog signal conditioning from external components. The device operates from a 1.65 V to 3.6 V supply and offers multiple low-power modes down to a low-leakage standby state, making it suited for energy-scavenging and coin-cell products.
Technically, the autonomous dynamic voltage scaling regulator adjusts core voltage to the operating frequency, cutting dynamic power while preserving wake-up latency. The five low-power modes (Sleep, Low-power Run, Low-power Sleep, Stop, Standby) let designers trade wake-up time against current draw precisely.
Typical applications include battery-powered metering, portable medical monitoring, and industrial sensor nodes using USB connectivity for configuration and data upload.
A key design consideration: in Stop and Standby modes the low-speed oscillator domain remains critical for RTC-based wake-up, so layout and clock tree configuration deserve early attention.
This page synthesizes distributor pricing, drop-in alternatives, pinout, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for STM32L151RCT6 β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
STM32L151RCT6A
β Drop-Inπ Reference alternative (not in catalog)
STM32L152RCT6A
β Drop-Inπ Reference alternative (not in catalog)
STM32L151RBT6A
β Drop-Inπ Reference alternative (not in catalog)
STM32L151R8T6
β Drop-Inπ Reference alternative (not in catalog)
STM32L151RCT6 Maximum Ratings & Electrical Characteristics
| Core | ARM Cortex-M3 32-bit |
| Maximum CPU Frequency | 32 MHz |
| Flash Memory | 256 KB |
| RAM | 32 KB |
| Supply Voltage Range | 1.65 V to 3.6 V |
| USB | USB 2.0 full-speed device |
| Analog Peripherals | 3x op-amp |
| Low-Power Modes | 5 (Sleep, Low-power Run, Low-power Sleep, Stop, Standby) |
| Process Technology | Ultra-low-leakage with autonomous dynamic voltage scaling |
| Package | 64-LQFP (10x10 mm) |
| Mounting Type | Surface Mount |
| Series | STM32L1 (Ultra-low-power) |
| Instruction Set | ARMv7-M (Thumb-2) |
| RoHS Status | Compliant |
| Data Connectors | USB (device mode) |
STM32L151RCT6 Pin Configuration
| Pin 1 | VBAT β Backup battery supply for RTC and backup registers |
| Pin 2 | PC13 β GPIO port C, pin 13 / TAMPER-RTC |
| Pin 3 | PC14 β GPIO port C, pin 14 / OSC32_IN |
| Pin 4 | PC15 β GPIO port C, pin 15 / OSC32_OUT |
| Pin 5 | PH0 β Oscillator input / OSC_IN |
| Pin 6 | PH1 β Oscillator output / OSC_OUT |
| Pin 7 | NRST β System reset (active low) |
| Pin 8 | PC0 β GPIO port C, pin 0 / ADC input |
| Pin 9 | PC1 β GPIO port C, pin 1 / ADC input |
| Pin 10 | PC2 β GPIO port C, pin 2 / ADC input |
| Pin 11 | PC3 β GPIO port C, pin 3 / ADC input |
| Pin 12 | VSSA β Analog ground |
| Pin 13 | VDDA β Analog power supply |
| Pin 14 | PA0 β GPIO port A, pin 0 / WKUP / ADC |
| Pin 15 | PA1 β GPIO port A, pin 1 / ADC |
| Pin 16 | PA2 β GPIO port A, pin 2 / USART2_TX / ADC |
| Pin 17 | PA3 β GPIO port A, pin 3 / USART2_RX / ADC |
| Pin 18 | VDD β Digital power supply |
| Pin 19 | PA4 β GPIO port A, pin 4 / SPI1_NSS / DAC / ADC |
| Pin 20 | PA5 β GPIO port A, pin 5 / SPI1_SCK / DAC / ADC |
| Pin 21 | PA6 β GPIO port A, pin 6 / SPI1_MISO / ADC |
| Pin 22 | PA7 β GPIO port A, pin 7 / SPI1_MOSI / ADC |
| Pin 23 | PC4 β GPIO port C, pin 4 / ADC |
| Pin 24 | PC5 β GPIO port C, pin 5 / ADC |
| Pin 25 | PB0 β GPIO port B, pin 0 / ADC |
| Pin 26 | PB1 β GPIO port B, pin 1 / ADC |
| Pin 27 | PB2 β GPIO port B, pin 2 / BOOT1 |
| Pin 28 | PB10 β GPIO port B, pin 10 / I2C2_SCL / USART3_TX |
| Pin 29 | PB11 β GPIO port B, pin 11 / I2C2_SDA / USART3_RX |
| Pin 30 | VSS β Digital ground |
| Pin 31 | VDD β Digital power supply |
| Pin 32 | PB12 β GPIO port B, pin 12 / SPI2_NSS |
| Pin 33 | PB13 β GPIO port B, pin 13 / SPI2_SCK |
| Pin 34 | PB14 β GPIO port B, pin 14 / SPI2_MISO |
| Pin 35 | PB15 β GPIO port B, pin 15 / SPI2_MOSI |
| Pin 36 | PC6 β GPIO port C, pin 6 |
| Pin 37 | PC7 β GPIO port C, pin 7 |
| Pin 38 | PC8 β GPIO port C, pin 8 |
| Pin 39 | PC9 β GPIO port C, pin 9 |
| Pin 40 | PA8 β GPIO port A, pin 8 / USART1_CK / MCO |
| Pin 41 | PA9 β GPIO port A, pin 9 / USART1_TX / VBUS sensing |
| Pin 42 | PA10 β GPIO port A, pin 10 / USART1_RX |
| Pin 43 | PA11 β GPIO port A, pin 11 / USB_DM |
| Pin 44 | PA12 β GPIO port A, pin 12 / USB_DP |
| Pin 45 | PA13 β GPIO port A, pin 13 / SWDIO |
| Pin 46 | VSS β Digital ground |
| Pin 47 | VDD β Digital power supply |
| Pin 48 | PA14 β GPIO port A, pin 14 / SWCLK |
| Pin 49 | PA15 β GPIO port A, pin 15 / SPI1_NSS / JTDI |
| Pin 50 | PC10 β GPIO port C, pin 10 |
| Pin 51 | PC11 β GPIO port C, pin 11 |
| Pin 52 | PC12 β GPIO port C, pin 12 |
| Pin 53 | PD2 β GPIO port D, pin 2 / USART3_RX |
| Pin 54 | PB3 β GPIO port B, pin 3 / SPI1_SCK / JTDO |
| Pin 55 | PB4 β GPIO port B, pin 4 / SPI1_MISO / NJTRST |
| Pin 56 | PB5 β GPIO port B, pin 5 / SPI1_MOSI |
| Pin 57 | PB6 β GPIO port B, pin 6 / I2C1_SCL / USART1_TX |
| Pin 58 | PB7 β GPIO port B, pin 7 / I2C1_SDA / USART1_RX |
| Pin 59 | BOOT0 β Boot mode selection |
| Pin 60 | PB8 β GPIO port B, pin 8 / I2C1_SCL |
| Pin 61 | PB9 β GPIO port B, pin 9 / I2C1_SDA |
| Pin 62 | VSS β Digital ground |
| Pin 63 | VDD β Digital power supply |
| Pin 64 | NC β Not connected (per datasheet) |
Typical Applications
STM32L151RCT6 is suitable for 6 applications: Smart Energy Metering, Portable Medical Monitoring, Industrial Sensor Nodes, USB Data Loggers and Dongles, Remote Controls and Consumer Devices, IoT Sensor Endpoints.
Smart Energy Metering
The STM32L151RCT6 fits electricity, water, and gas metering because its ultra-low-leakage process and five low-power modes minimize battery drain over a 10+ year service life, while the 256 KB Flash stores metrology firmware, calibration tables, and logging buffers without external memory. The three integrated op-amps amplify shunt or CT sensor signals on-chip, reducing BOM cost and quiescent current versus external amplifiers. In typical designs the MCU spends most time in Stop mode with RTC wake-up, sampling sensors periodically; USB FS enables in-field configuration via optical or wired service tools. The 1.65-3.6 V supply range tolerates lithium thionyl chloride cells directly.
Recommended
Portable Medical Monitoring
Wearable and portable medical devices benefit from the STM32L151RCT6's 32 MHz Cortex-M3 performance for digital filtering and its ultra-low-power profile for multi-day battery operation between charges. The 32 KB RAM buffers ECG or SpO2 waveform data, while the on-chip op-amps condition bio-potential or optical sensor front-ends with minimal noise-adding circuitry. USB full-speed allows charging cradles to double as data-upload links to clinician software. According to the STMicroelectronics product page, autonomous dynamic voltage scaling keeps active-mode efficiency high, so burst-processing workloads do not penalize average battery life the way fixed-voltage-core MCUs do.
Recommended
Industrial Sensor Nodes
Factory and process sensor nodes use the STM32L151RCT6 to acquire analog signals (via its three op-amps and ADC), process them locally on the 32 MHz Cortex-M3, and report over wired buses; USB FS doubles as a commissioning interface during installation. The five low-power modes allow duty-cycled acquisition from energy-harvesting or long-life battery supplies, and the 1.65-3.6 V range suits 3.3 V and 3.6 V industrial rails. With 256 KB Flash, nodes store compensation curves and logging data on-device. The 64-pin LQFP provides enough GPIO for multi-sensor input and relay or 4-20 mA transmitter control outputs.
Recommended
USB Data Loggers and Dongles
The integrated USB 2.0 full-speed device controller makes the STM32L151RCT6 a natural fit for battery-powered loggers and USB dongles that must also run standalone. The 48 MHz USB clock is derived from the internal PLL, simplifying the clock tree, and ST's USB device library provides CDC/HID/MSC classes. The 256 KB Flash supports USB DFU in-field firmware updates alongside the application. In typical logger designs the MCU sleeps in Stop mode, wakes on RTC or sensor interrupt, records to RAM or SPI Flash, and enumerates only when plugged in - USB session presence is managed via the VBUS sensing path on the PA9 alternate function.
Recommended
Remote Controls and Consumer Devices
Consumer products with years of shelf life - remote controls, thermostats, fitness accessories - leverage the STM32L151RCT6's standby leakage performance. The ultra-low-leakage process keeps Standby current in the sub-uA region so a coin cell survives typical product lifetimes. The 32 MHz core handles capacitive-touch scanning, IR protocols, and Bluetooth-module management, while 256 KB Flash leaves room for OTA-capable firmware. The 1.65-3.6 V range covers single lithium CR2032 and 2x alkaline stacks. The three op-amps can implement touch-signal conditioning or sensor front-ends, trimming BOM in high-volume consumer designs.
Recommended
IoT Sensor Endpoints
Battery-powered IoT endpoints pair the STM32L151RCT6 with sub-GHz or 2.4 GHz radio modules; the MCU handles sensor acquisition (on-chip op-amps conditioning analog outputs), protocol stacks, and security routines while radios sleep. Five low-power modes let firmware shut the core between report intervals, and dynamic voltage scaling keeps active bursts efficient. The 32 KB RAM accommodates TLS session buffers, and 256 KB Flash leaves margin for bootloader plus radio firmware-update logic. The 64-pin LQFP-64 (10x10 mm) provides sufficient GPIO for SPI/I2C radio, sensor, and power-management circuitry within a compact endpoint footprint.
Recommended
Recommended Products Summary
Engineering reference data for STM32L151RCT6 β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | STM32L151RCT6A | STM32L152RCT6A | STM32L151RBT6A | STM32L151R8T6 |
|---|---|---|---|---|---|
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics |
| Package | 64-LQFP (10x10 mm) | 64-LQFP (10x10 mm) - same | 64-LQFP (10x10 mm) - same | 64-LQFP (10x10 mm) - same | 64-LQFP (10x10 mm) - same |
| Core / Frequency | Cortex-M3, 32 MHz | Cortex-M3, 32 MHz | Cortex-M3, 32 MHz | Cortex-M3, 32 MHz | Cortex-M3, 32 MHz |
| Flash Memory | 256 KB | 256 KB | 256 KB | 128 KB | 64 KB |
| USB | USB FS device | USB FS device | USB FS device | USB FS device | USB FS device |
| Op-amps | 3x | 3x | 3x | 3x | 3x |
| LCD Controller | No | No | Yes (8x40 segments) | No | No |
| Drop-in Compatibility | Reference | Full drop-in (same die family) | Pin-compatible, LCD-enabled firmware differs | Pin-compatible, Flash-limited | Pin-compatible, Flash-limited |
| Lifecycle Status | Active | Active | Active | Active | Active |
Key Differentiators
- On-chip 3x op-amps eliminate external analog front-end (vs STM32L151RBT6A)
- Larger Flash than pin-compatible cost-downs (vs STM32L151R8T6)
- No LCD controller vs L152 variant (vs STM32L152RCT6A)
Design Notes
Connect VDDA to a clean filtered supply (ferrite bead plus 100 nF and 1 uF capacitors) even if digital VDD is already clean - the on-chip op-amps and ADC reference this rail, and digital noise on VDDA directly degrades analog accuracy. VBAT should be tied to VDD through a 3.3 V domain or to a coin cell if RTC retention through battery removal is required. Estimated: a coin-cell CR2032 (~220 mAh) powering a design sleeping at 2 uA and active 10 mA for 2% duty averages roughly 0.22 mA, yielding around 1 year of runtime.
Place 100 nF decoupling capacitors within 2 mm of each VDD/VSS pin pair; the LQFP-64 has four VDD/VDDA pairs that all require local decoupling. Keep the USB DM/DP pair (PA11/PA12) as a 90-ohm differential pair routed away from the 32.768 kHz crystal and the HSE oscillator. Ground the NRST pin with a 100 nF capacitor close to pin 7 for reliable power-on reset. Use BOOT0 with a pulldown (10k) to guarantee execution from Flash at reset.
USB operation requires the internal voltage regulator enabled and the 48 MHz USB clock from the PLL - entering Stop mode kills the USB session, so applications must disconnect from the bus before deep sleep and re-enumerate on wake. PC14/PC15 and PH0/PH1 are low-drive pins with limited sink capability when used as GPIO. Flash endurance is limited for frequent parameter writes; use the EEPROM-like emulation or external FRAM for high-cycle logging. Verify the silicon revision (RCT6 vs RCT6A errata) against the ST Errata Sheet during development.
Compliance Information
RoHS compliant per STMicroelectronics product data; T6 suffix denotes RoHS-compliant package. REACH and halogen-free status not stated in provided data.
