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LQFP-48 · STM32F103CBT6
Active32-bit ARM MCU
STM32F103CBT6
STMicroelectronics · LQFP-48 · 32-bit ARM MCU
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Get a competitive quote within 24 hours. Volume discounts available. Shenzhen stock ships in 1-2 business days.
Overview
The STM32F103CBT6 is the 128 KB Flash variant of ST's most popular ARM Cortex-M3 microcontroller, pin-compatible and functionally identical to the STM32F103C8T6 (64 KB Flash) in the same LQFP-48 package. If your C8T6 firmware has grown past 60 KB — adding USB stack, RTOS, file system, DSP libraries, BLE stack or extensive UI logic — the CBT6 is a zero-hardware-change upgrade path: drop the new chip on the same PCB, reflash with the same toolchain, and gain 64 KB of code space.
The core is the ARM Cortex-M3 running at up to 72 MHz with 1.25 DMIPS/MHz, supported by 20 KB SRAM, a nested vectored interrupt controller (NVIC) with 60 maskable channels, and a full DMA controller set. Peripheral integration mirrors C8T6: two 12-bit ADCs at 1 MSPS with 16 total channels, three 16-bit general-purpose timers plus one advanced-control timer with complementary PWM outputs for motor drive, two I²C, two SPI, three USART, one full-speed USB 2.0 device, and one bxCAN 2.0B.
Operating voltage is 2.0 V to 3.6 V, temperature range -40 to +85 °C, package LQFP-48 (7×7 mm, 0.5 mm pitch). Programming is via SWD (serial wire debug) using ST-Link, J-Link or any CMSIS-DAP probe; the built-in ROM bootloader also supports UART, I²C, SPI, CAN and USB DFU.
Counterfeit risk on the F103CBT6 is significant — broker markets are flooded with remarked C8T6 dies (64 KB Flash) sold as CBT6 (128 KB), and with Chinese CKS32F103 clones that share the same markings. Always verify by reading the Flash size register at address 0x1FFFF7E0: genuine CBT6 reads 0x0080 (128 KB). Our authorized ST channel guarantees genuine dies with batch traceability and full C-of-C documentation.
Our Shenzhen stock: LQFP-48 STM32F103CBT6, MOQ 1 tray (250 pcs) or 90 pcs on tape-and-reel for prototyping.
Key Features
- Drop-in upgrade from STM32F103C8T6 — same LQFP-48 pinout
- 128 KB Flash + 20 KB SRAM (2× Flash of C8T6)
- ARM Cortex-M3 @ 72 MHz with full peripheral set
- USB device + bxCAN + 3 USART + 2 SPI + 2 I²C
Typical Applications
- IoT gateways with USB and Ethernet stacks
- Industrial controllers running RTOS and Modbus/CANopen
- 3D-printer and CNC controller boards (Marlin, Grbl)
- Consumer appliances with rich UI logic
- Firmware-heavy designs that outgrew the C8T6 64 KB Flash
Specifications
- Core
- ARM Cortex-M3
- Max Clock
- 72 MHz
- Flash
- 128 KB
- SRAM
- 20 KB
- Supply Voltage
- 2.0 to 3.6 V
- ADC
- 2x 12-bit
- Operating Temperature
- -40 to 85 °C
- Pins
- 48
- RoHS
- Compliant
Procurement Tips
For new designs, evaluate STM32F303CBT6 or STM32G0B1CBT6 — same LQFP-48 footprint, more modern cores (Cortex-M4 with FPU or Cortex-M0+ at 64 MHz), better peripherals, and often lower cost than F103CBT6.
Frequently Asked Questions
Can I use STM32F103CBT6 as a drop-in replacement for C8T6?
Yes — same LQFP-48 pinout, same peripheral map, same voltage range, same debug interface. Your firmware will run unchanged on CBT6; just update the linker script to reflect 128 KB Flash instead of 64 KB. No PCB respin needed.
Is CBT6 counterfeit-prone?
Yes, heavily. Common frauds: remarked C8T6 dies (only 64 KB Flash) sold as CBT6, Chinese CKS32F103 clones with identical markings, and pulled chips from e-waste. Verify by reading Flash size register at 0x1FFFF7E0 — genuine CBT6 reads 0x0080. We X-ray and electrically test every tray.
What's the price difference between C8T6 and CBT6?
In volume (10k+ pcs) the difference is typically $0.10-0.30 — negligible. For prototypes and small batches the gap is larger (~$0.50-1.00) because C8T6 has more competition from clones. Always spec CBT6 for new designs; the insurance is cheap.
Can I program CBT6 with an ST-Link V2?
Yes — any ST-Link V2, V2-1, V3 or J-Link works. Connect SWDIO (pin 46), SWCLK (pin 49), GND, and 3.3 V. Use STM32CubeProgrammer, OpenOCD, or the ST-Link Utility.
Does CBT6 run at 72 MHz from 3.3 V?
Yes, at 2.7-3.6 V supply. Below 2.7 V, maximum frequency drops to 24 MHz per the voltage-frequency scaling table. Always check this when running from a Li-ion cell that sags under load.
MOQ and lead time?
MOQ 1 tray (250 pcs) or 90 pcs on cut tape. ST authorized 8-14 weeks during allocation; Shenzhen stock typically ships same-day for quantities under 5,000 pcs.
Is STM32F103 series EOL?
ST has declared F1 series Active with no announced EOL. However, for new designs ST pushes F3/G0/L4 series. F103 remains fully supported for at least 10 more years under ST's longevity commitment.
Alternatives & Equivalents
STM32F103C8T6
STMicroelectronics
upgrade alternative
STM32F407VGT6
STMicroelectronics
upgrade alternative
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