STMicroelectronics STM32F091CBT6

Overview

STM32F091CBT6 from STMicroelectronics is a 32-bit ARM® Cortex®-M0 microcontroller with 128 KB Flash, 32 KB SRAM (with hardware parity), and integrated CAN 2.0B interface - designed for real-time industrial control, motor drive supervision, and smart sensor nodes operating from 2.0–3.6 V supply. It delivers 48 MHz CPU performance, features dual 12-bit DAC channels, a 12-bit 1 µs ADC (16-channel), and supports capacitive touch sensing across up to 24 channels.

For engineers reviewing the STM32F091CBT6 datasheet, STM32F091CBT6 pinout, STM32F091CBT6 application, or STM32F091CBT6 equivalent, key selection considerations include its 48-pin LQFP package with 39 I/Os (including 5V-tolerant pins), embedded RTC with calendar and alarm, advanced-control timer (TIM1) for 6-channel PWM, and SWD debug support - all critical for deterministic firmware deployment in resource-constrained embedded systems.

Technical Context

The STM32F091CBT6 implements a single-cycle ARM Cortex-M0 core with Thumb-2 instruction set, tightly coupled to a 32 KB SRAM with hardware parity checking and 128 KB Flash supporting read-while-write and 100k write/erase cycles. Its clock system integrates multiple oscillators: 4–32 MHz HSE, 32 kHz LSE for RTC, 8 MHz HSI with x6 PLL, and a factory-trimmed 48 MHz HSI48 oscillator enabling USB-free device enumeration.

Peripheral integration includes two I²C interfaces (one Fast Mode Plus at 1 Mbit/s), eight USARTs (three with ISO7816/LIN/IrDA), two SPI/I²S modules (18 Mbit/s), a CAN 2.0B controller, and a dedicated touch-sensing controller (TSC) with spread-spectrum modulation - all mapped to GPIOs via programmable alternate function registers and supported by a 12-channel DMA controller with memory-to-memory transfers.

Key Specifications

Pinout & Package

LQFP48 (7 × 7 mm, 0.5 mm pitch) package with exposed thermal pad - optimized for compact PCB layouts and moderate power dissipation (<200 mW typical active mode).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microcontroller applications.

Compared with STM32F091CBT6, STM32F072CBT6 trades CAN for USB and drops touch sensing, while STM32F098C8T6 sacrifices CAN and half the Flash for USB OTG - making STM32F091CBT6 uniquely balanced for CAN+touch+RTC applications in space-constrained LQFP48 designs.

Availability

STM32F091CBT6 is available at Aetrix Electronics and suitable for industrial motor control, smart energy metering, human-machine interface (HMI), and automotive body control modules requiring stable component supply across extended temperature ranges (–40°C to +85°C).

Supply support for STM32F091CBT6 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, specializing in microcontrollers, power management, sensors, and automotive ICs - with over 40 years of embedded systems expertise.

The STM32F0 series targets cost-sensitive, ultra-low-power applications requiring high integration and industrial-grade reliability - specifically engineered for appliance control, industrial automation, and smart metering where Flash size, peripheral mix, and package footprint are critical constraints.

FAQ

Does STM32F091CBT6 support USB device functionality?

No. The STM32F091CBT6 does not integrate a USB transceiver or USB controller. While some STM32F09x variants (e.g., STM32F072, STM32F098) include USB 2.0 Full-Speed device or OTG, the STM32F091CBT6 omits USB entirely to prioritize CAN, TSC, and enhanced analog capabilities - confirmed in Section 3.20 (CAN) and absence of USB-related registers in RM0091 reference manual.

What is the maximum operating frequency of the internal HSI48 oscillator?

The internal HSI48 oscillator operates at a nominal 48 MHz with automatic trimming based on external synchronization (e.g., USB SOF or LSE pulses), maintaining ±0.25% accuracy over temperature and voltage - enabling precise USB-free device enumeration and clocking of high-speed peripherals like SPI and USART without external crystals.

How many I/O pins are 5V-tolerant on the LQFP48 package?

39 GPIO pins are available in the LQFP48 package, of which 22 are 5V-tolerant: PA0–PA7, PB0–PB1, and PC13–PC15. This is explicitly defined in Table 13 (pin definitions) and Section 3.7 (GPIOs) of the datasheet - allowing direct interfacing with 5 V sensors, displays, or logic without external level-shifting circuitry.

Is the RTC battery-backed in STM32F091CBT6?

Yes. The RTC and 40-byte backup register block retain state during main power loss using an external VBAT supply (1.8–3.6 V), supported by an internal diode-OR circuit that automatically switches between VDD and VBAT - enabling calendar timekeeping and non-volatile parameter storage even when system power is removed, as detailed in Section 3.15 and Figure 14 of the datasheet.