STM32F103CBT6
Brand: ST
The STM32F103CBT6 belongs to ST's STM32F1 Performance Line — the series that defined the ARM Cortex-M3 ecosystem in the maker, hobbyist, and professional drone communities. Its combination of 72 MHz processing, extensive communication peripherals, hardware PWM for motor control, and industrial temperature range makes it the natural choice for flight controllers spanning micro whoops to professional mapping UAVs.
With 128 KB Flash — double that of the ubiquitous C8T6 — the STM32F103CBT6 provides generous headroom for Betaflight builds incorporating OSD fonts, detailed Blackbox logging, soft-serial ports, and LED strip control without hitting the firmware size ceiling. The LQFP-48 package brings 37 GPIO to the table for expanded sensor and actuator connectivity.
Product Specifications
STM32F103CBT6 — ARM Cortex-M3 MCU for Drone Flight Controllers by STMicroelectronics
The STM32F103CBT6 is STMicroelectronics' medium-density mainstream line 32-bit ARM Cortex-M3 microcontroller, running at 72 MHz with 128 KB Flash and 20 KB SRAM. Packaged in a LQFP-48, it serves as the flight controller brain for open-source drone firmware — Betaflight, Cleanflight, iNav, and ArduPilot — across board designs from micro AIO whoops to full-size professional mapping UAVs. With 2× 12-bit (10 channels), 7-channel, and a comprehensive set of communication interfaces (USART, SPI, I²C, CAN, USB), it delivers a complete sensor-fusion and motor-control pipeline for the global drone ecosystem.
Part Number Decoded — Field by Field
| Field | Value | Meaning |
|---|---|---|
| STM32 | Product Family | STMicroelectronics 32-bit ARM-based MCU |
| F | Core Type | Foundation — general-purpose mainstream series (ARM Cortex-M3) |
| 103 | Sub-Family | Performance Line — 72 MHz, motor control capable, USB & CAN available |
| C | Pin Count | 48 pins (LQFP-48) |
| B | Flash Size | 128 KB |
| T | Package | LQFP (Low-profile Quad Flat Package) |
| 6 | Temperature Range | −40°C to +85°C (industrial) |
Quick Specifications
| Parameter | Value |
|---|---|
| Manufacturer | STMicroelectronics |
| Part Number | STM32F103CBT6 |
| Core | ARM Cortex-M3 |
| Max Clock | 72 MHz |
| Flash | 128 KB |
| SRAM | 20 KB |
| Package | LQFP-48 |
| Supply Voltage | 2.0V – 3.6V |
| Operating Temperature | −40°C to +85°C |
| GPIO | 37 |
| ADC | 2× 12-bit (10 channels) |
| Timers | 3× 16-bit GP, 1× 16-bit advanced (PWM), 2× watchdog, 1× SysTick |
| Communication | 3× USART, 2× SPI (18 Mbit/s), 2× I²C, 1× CAN 2.0B, 1× USB 2.0 Full Speed |
| DMA | 7-channel |
| Debug | SWD + JTAG |
Product Overview
The STM32F103CBT6 belongs to ST's STM32F1 Performance Line — the series that defined the ARM Cortex-M3 ecosystem in the maker, hobbyist, and professional drone communities. Its combination of 72 MHz processing, extensive communication peripherals, hardware PWM for motor control, and industrial temperature range makes it the natural choice for flight controllers spanning micro whoops to professional mapping UAVs.
With 128 KB Flash — double that of the ubiquitous C8T6 — the STM32F103CBT6 provides generous headroom for Betaflight builds incorporating OSD fonts, detailed Blackbox logging, soft-serial ports, and LED strip control without hitting the firmware size ceiling. The LQFP-48 package brings 37 GPIO to the table for expanded sensor and actuator connectivity.
Key Features & Benefits
72 MHz ARM Cortex-M3 — 48-Pin Flight Controller Powerhouse
At 72 MHz with single-cycle multiply and hardware divide, the Cortex-M3 core delivers deterministic real-time control for drone flight stabilization. It sustains a 4 kHz gyroscope update rate with PID loops running on 4–6 motor axes — the practical performance ceiling for SPI-gyro-based flight controllers in the F103 class, without overclocking or migrating to F4 silicon.
128 KB Flash + 20 KB SRAM — Double the Flash of the C8T6
With 128 KB Flash, the STM32F103CBT6 doubles the code space of the standard 64 KB F103 variants. This is the practical minimum for Betaflight builds with OSD, Blackbox logging, LED strip control, and soft-serial — all enabled simultaneously without hitting the linker limit.
Industrial Temperature −40°C to +85°C — Outdoor-Ready
The temperature suffix guarantees operation from −40°C to +85°C — essential for drones flying in cold high-altitude environments, agricultural UAVs operating in extreme heat, and industrial inspection platforms where reliability across thermal cycles is non-negotiable.
7-channel — Offloads IMU and Serial Transfers
The 7-channel offloads SPI gyro/accelerometer reads, USART telemetry streaming (CRSF, SmartPort, MSP), and I²C barometer/magnetometer polling from the CPU — freeing core cycles for the PID control loop and enabling lower-latency flight characteristics.
Advanced Timer with 6 Hardware PWM Channels — Quadcopter to Hexacopter
One 16-bit advanced-control timer with complementary outputs and dead-time insertion drives up to 6 independent PWM channels — directly supporting quadcopter (4 motors), hexacopter (6 motors), and servo-driven tricopter configurations using protocols from standard PWM through Oneshot125, Multishot, and DShot (bit-banged).
USB 2.0 Full Speed + CAN 2.0B — One Cable for Config, One Bus for Expansion
The on-chip USB 2.0 Full Speed peripheral eliminates external USB-UART ICs (e.g., CP2102, CH340G), reducing BOM cost and board complexity. The CAN 2.0B interface enables integration with UAVCAN/DroneCAN peripherals (GPS modules, airspeed sensors, ESC telemetry nodes) for modular, future-proof drone architectures.
Target Applications
Entry-Level Drone Flight Controllers
The STM32F103CBT6 powers compact Betaflight and Cleanflight flight controllers in the 48-pin format, ideal for 2″–5″ micro quads, toothpick drones, and AIO (all-in-one) FC/ESC boards where PCB real estate is at a premium. With 128 KB Flash and 20 KB SRAM, it runs optimized Betaflight 3.x/4.0.x F3 targets with gyro loop rates up to 4 kHz using SPI-attached MPU6000/ICM-20602 IMUs.
ArduPilot Minimal / Accessory Processor
The STM32F103CBT6 can run lightweight ArduPilot builds (ChibiOS) with carefully pruned feature sets — viable for basic fixed-wing stabilization, simple waypoint navigation, or as a dedicated sensor-fusion coprocessor feeding pre-processed attitude data to a companion computer over USART.
Sensor Hub & Companion Processor
As a dedicated sensor-fusion node, the STM32F103CBT6 offloads IMU (MPU6000/ICM-20602), barometer (BMP280/MS5611), magnetometer (QMC5883L), and GPS (UBlox NEO-M8) processing from a host application processor (Raspberry Pi, Jetson Nano, or STM32H7). It streams pre-filtered attitude quaternions and altitude data via USART or SPI at configurable rates up to 1 kHz.
Robotics Motor Controllers
The advanced PWM timer with up to 6 channels drives BLDC/ESC motor protocols (PWM, Oneshot125, Multishot, DShot) for small ground robots, gimbals, and pan-tilt systems. The CAN 2.0B interface enables integration into distributed robotic architectures.
Educational & Maker Platforms
Variants like the STM32F103CBT6 power the 'Blue Pill' ecosystem of ARM development boards — one of the most widely cloned and taught MCU platforms globally. Supported by Arduino (STM32duino), PlatformIO, STM32CubeIDE, and MicroPython, it is the default choice for university embedded systems courses, hackathons, and open-source IoT prototypes.
Industrial Sensor & Actuator Nodes
In industrial environments, the STM32F103CBT6 serves as a low-cost Modbus RTU (RS-485) or CANopen slave node, bridging analog sensors (4–20 mA, 0–10V) and digital actuators to PLCs and SCADA systems. The −40°C to +85°C temperature range and 2.0V–3.6V supply suit unregulated industrial power rails.
F103 Series Variant Comparison
| Feature | STM32F103CBT6 | STM32F103RCT6 | STM32F103VCT6 | STM32F103VET6 |
|---|---|---|---|---|
| Package | LQFP-48 | LQFP-64 | LQFP-100 | LQFP-100 |
| Flash | 128 KB | 256 KB | 256 KB | 512 KB |
| SRAM | 20 KB | 48 KB | 48 KB | 64 KB |
| GPIO | 37 | 51 | 80 | 80 |
| USART | 3 | 3 | 5 | 5 |
| SPI | 2 | 3 | 3 | 3 |
| FPU | No (Cortex-M3 — no hardware FPU) | |||
| Best For | Betaflight, more Flash headroom | ArduPilot fixed-wing, iNav, Betaflight | Complex drone & industrial, iNav | Complex drone & industrial, iNav |
STM32F103 vs Competing Entry-Level Flight Controller MCUs
| Feature | STM32F103CBT6 (ST) | GD32F103C8T6 (GigaDevice) | AT32F403AC8T6 (Artery) | APM32F103C8T6 (Geehy) |
|---|---|---|---|---|
| Core | ARM Cortex-M3 @ 72 MHz | ARM Cortex-M3 @ 108 MHz | ARM Cortex-M4F @ 240 MHz | ARM Cortex-M3 @ 96 MHz |
| Flash / SRAM | 128 KB / 20 KB | 64 KB / 20 KB | 64 KB / 96 KB | 64 KB / 20 KB |
| Package | LQFP-48 | LQFP-48 | LQFP-48 | LQFP-48 |
| FPU | No | No | Yes (single-precision) | No |
| Betaflight Support | F3 target (up to BF 4.0.x) | Unofficial (F3 port) | No (M4F arch diff) | No |
| Availability (Q3 2026) | Stable, 8–12 week lead | Good (domestic China) | Good | Good |
Frequently Asked Questions
What is the difference between STM32F103CBT6 and STM32F103C8T6?
The CBT6 has 128 KB Flash while the C8T6 has 64 KB Flash. SRAM (20 KB), LQFP-48 pinout, and all peripherals are identical. If your Betaflight/ArduPilot build needs more code space for logging, OSD fonts, or additional flight features, choose the CBT6. Standard builds run fine on the C8T6.
How do I flash firmware to the STM32F103CBT6?
Flash via Betaflight Configurator (or STM32CubeProgrammer) over USB DFU: (1) Assert BOOT0 high (connect to 3.3V or press BOOT button if present). (2) Connect USB — the MCU enters the ROM serial bootloader. (3) In Betaflight Configurator select "STM32F103" as target, load the .hex firmware, click "Flash Firmware." After flashing, return BOOT0 to GND and reconnect USB for normal COM-port operation. For production, SWD (ST-Link/V2) is faster and does not require BOOT0 manipulation.
Can the STM32F103CBT6 run Betaflight 4.4+?
No. Betaflight dropped official F3 target support after BF 4.0.x. The STM32F103 (Cortex-M3) is classified as an F3 target. For Betaflight 4.4+, an STM32F405/F411/F722/F745/H743 (F4 or F7 target) is required. The STM32F103CBT6 remains viable for legacy Betaflight 3.x/4.0.x builds and for Cleanflight/iNav F3 targets with feature limitations.
Is the STM32F103CBT6 affected by semiconductor shortages in 2026?
As of mid-2026, STM32F103 supply has normalized significantly versus the 2021–2023 crisis. Lead times are 8–12 weeks, and spot-market availability through Asia-based distributors is good. However, volume pricing remains elevated above pre-shortage levels. SUPERB Automation maintains relationships with multiple authorized and independent channels to secure competitive pricing and consistent delivery.
What is the minimum order quantity (MOQ) for the STM32F103CBT6?
Contact SUPERB Automation for a tailored quote. We support quantities from prototype tray (1–10 pcs) to full production volumes. Send your target quantity and delivery timeline — we provide competitive pricing with full traceability and batch-level QA documentation.
Ordering Information
| Orderable Part Number | Package | Packaging | Temperature |
|---|---|---|---|
| STM32F103CBT6 | LQFP-48 | Tray (250 pcs/tray) | −40°C to +85°C |
| STM32F103CBT6TR | LQFP-48 | Tape & Reel (2,400 pcs/reel) | −40°C to +85°C |
Design Resources
Datasheet: STM32F103x8/xB — Complete datasheet with pin definitions, electrical characteristics (I/O DC/AC parameters, current consumption, timing), and package mechanical drawings.
Reference Manual (RM0008): STM32F1xx advanced ARM-based 32-bit MCUs — Full register-level documentation covering all peripherals (GPIO, timers, ADC, USART, SPI, I²C, CAN, USB, DMA, RCC, PWR).
Betaflight GitHub:
betaflight/betaflight— Open-source flight controller firmware with STM32F103 (F3) target support (up to BF 4.0.x).STM32CubeIDE: Free ST development environment with STM32CubeMX graphical pinout/clock configurator and built-in GCC toolchain.
AN2586 Application Note: Getting started with STM32F10xxx hardware development — hardware design guidelines, PCB layout recommendations, and oscillator/decoupling requirements.
Request a Quote
SUPERB Automation supplies genuine STMicroelectronics STM32F103CBT6 MCUs with full traceability and batch-level QA documentation. Whether you need a single tray for prototype drone FC builds or pallet-level volumes for production, we source through verified channels with competitive lead times. Contact us with your target quantity, delivery date, and any special packaging or marking requirements — we'll respond with a detailed quotation within 24 hours.