STM32F103CBT6 from STMicroelectronics, in a LQFP-48(7x7). Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	VBAT	power_in	Backup battery supply, 1.8 V to 3.6 V. Powers the RTC, LSE oscillator and backup registers when VDD is off.
2	PC13-TAMPER-RTC	bidirectional	GPIO PC13 with alternate function TAMPER input / RTC calibration output. Supplied through the backup power switch (limited to 3 mA, ≤2 MHz, ≤30 pF).
3	PC14-OSC32_IN	bidirectional	GPIO PC14; alternate function LSE 32.768 kHz oscillator input (OSC32_IN). Backup-domain supply, limited drive when used as GPIO.
4	PC15-OSC32_OUT	bidirectional	GPIO PC15; alternate function LSE 32.768 kHz oscillator output (OSC32_OUT). Backup-domain supply, limited drive when used as GPIO.
5	PD0-OSC_IN	bidirectional	Configured as OSC_IN (HSE crystal input) after reset. Can be remapped as GPIO PD0 (limited to 50 MHz in output).
6	PD1-OSC_OUT	bidirectional	Configured as OSC_OUT (HSE crystal output) after reset. Can be remapped as GPIO PD1 (limited to 50 MHz in output).
7	NRST	bidirectional	Bidirectional device reset (active low). Internal pull-up; asserted by internal reset sources.
8	VSSA	power_in	Analog ground reference for the ADC and analog blocks. Tie to system ground with proper decoupling.
9	VDDA	power_in	Analog supply for the ADC, reset block, PLL and oscillators, 2.0-3.6 V. Must be present whenever VDD is powered.
10	PA0-WKUP	bidirectional	GPIO PA0 with WKUP wake-from-standby input; alt: USART2_CTS, ADC12_IN0, TIM2_CH1_ETR.
11	PA1	bidirectional	GPIO PA1; alt: USART2_RTS, ADC12_IN1, TIM2_CH2.
12	PA2	bidirectional	GPIO PA2; alt: USART2_TX, ADC12_IN2, TIM2_CH3.
13	PA3	bidirectional	GPIO PA3; alt: USART2_RX, ADC12_IN3, TIM2_CH4.
14	PA4	bidirectional	GPIO PA4; alt: SPI1_NSS, USART2_CK, ADC12_IN4.
15	PA5	bidirectional	GPIO PA5; alt: SPI1_SCK, ADC12_IN5.
16	PA6	bidirectional	GPIO PA6; alt: SPI1_MISO, ADC12_IN6, TIM3_CH1, TIM1_BKIN (remap).
17	PA7	bidirectional	GPIO PA7; alt: SPI1_MOSI, ADC12_IN7, TIM3_CH2, TIM1_CH1N (remap).
18	PB0	bidirectional	GPIO PB0; alt: ADC12_IN8, TIM3_CH3, TIM1_CH2N (remap).
19	PB1	bidirectional	GPIO PB1; alt: ADC12_IN9, TIM3_CH4, TIM1_CH3N (remap).
20	PB2	bidirectional	GPIO PB2 (5 V tolerant), doubles as BOOT1 boot-mode select at reset.
21	PB10	bidirectional	GPIO PB10 (5 V tolerant); alt: I2C2_SCL, USART3_TX, TIM2_CH3 (remap).
22	PB11	bidirectional	GPIO PB11 (5 V tolerant); alt: I2C2_SDA, USART3_RX, TIM2_CH4 (remap).
23	VSS_1	power_in	Digital ground return. Tie to system ground.
24	VDD_1	power_in	Digital supply 2.0-3.6 V. Decouple locally with a 100 nF capacitor.
25	PB12	bidirectional	GPIO PB12 (5 V tolerant); alt: SPI2_NSS, I2C2_SMBAl, USART3_CK, TIM1_BKIN (remap).
26	PB13	bidirectional	GPIO PB13 (5 V tolerant); alt: SPI2_SCK, USART3_CTS, TIM1_CH1N (remap).
27	PB14	bidirectional	GPIO PB14 (5 V tolerant); alt: SPI2_MISO, USART3_RTS, TIM1_CH2N (remap).
28	PB15	bidirectional	GPIO PB15 (5 V tolerant); alt: SPI2_MOSI, TIM1_CH3N (remap).
29	PA8	bidirectional	GPIO PA8 (5 V tolerant); alt: USART1_CK, TIM1_CH1, MCO (main clock output).
30	PA9	bidirectional	GPIO PA9 (5 V tolerant); alt: USART1_TX, TIM1_CH2.
31	PA10	bidirectional	GPIO PA10 (5 V tolerant); alt: USART1_RX, TIM1_CH3.
32	PA11	bidirectional	GPIO PA11 (5 V tolerant); alt: USART1_CTS, CANRX, USBDM (USB D-), TIM1_CH4.
33	PA12	bidirectional	GPIO PA12 (5 V tolerant); alt: USART1_RTS, CANTX, USBDP (USB D+), TIM1_ETR.
34	PA13	bidirectional	SWDIO / JTMS after reset (SWD data / JTAG mode select). Usable as GPIO PA13 (5 V tolerant) once debug alternate is disabled.
35	VSS_2	power_in	Digital ground return. Tie to system ground.
36	VDD_2	power_in	Digital supply 2.0-3.6 V. Decouple locally with a 100 nF capacitor.
37	PA14	bidirectional	SWCLK / JTCK after reset (SWD/JTAG clock). Usable as GPIO PA14 (5 V tolerant) once debug alternate is disabled.
38	PA15	bidirectional	JTDI after reset. Alt: TIM2_CH1_ETR, SPI1_NSS (remap); usable as GPIO PA15 (5 V tolerant) once JTAG disabled.
39	PB3	bidirectional	JTDO / TRACESWO after reset. Alt: TIM2_CH2 (remap), SPI1_SCK (remap); usable as GPIO PB3 (5 V tolerant) once JTAG disabled.
40	PB4	bidirectional	NJTRST after reset. Alt: TIM3_CH1 (remap), SPI1_MISO (remap); usable as GPIO PB4 (5 V tolerant) once JTAG disabled.
41	PB5	bidirectional	GPIO PB5 (not 5 V tolerant); alt: I2C1_SMBAl, TIM3_CH2 (remap), SPI1_MOSI (remap).
42	PB6	bidirectional	GPIO PB6 (5 V tolerant); alt: I2C1_SCL, TIM4_CH1, USART1_TX (remap).
43	PB7	bidirectional	GPIO PB7 (5 V tolerant); alt: I2C1_SDA, TIM4_CH2, USART1_RX (remap).
44	BOOT0	input	Boot-mode select input sampled at reset with BOOT1 (PB2). Selects boot from Flash, system memory or SRAM.
45	PB8	bidirectional	GPIO PB8 (5 V tolerant); alt: I2C1_SCL (remap), TIM4_CH3, CANRX (remap).
46	PB9	bidirectional	GPIO PB9 (5 V tolerant); alt: I2C1_SDA (remap), TIM4_CH4, CANTX (remap).
47	VSS_3	power_in	Digital ground return. Tie to system ground.
48	VDD_3	power_in	Digital supply 2.0-3.6 V. Decouple locally with a 100 nF capacitor.

Key specifications

Parameter	Value
Manufacturer	STMicroelectronics
Package	LQFP-48(7x7)
Category	MCU
Pins	48

Ordering variants

Same part, different packaging or reel option.

STM32F103CBT6
STM32F103CBT6CBT7
STM32F103CBT6CBU6
STM32F103CBT6TBU6
STM32F103CBT6RBT6
STM32F103CBT6RBH6
STM32F103CBT6VBT6

CAD (KiCad official)

Symbol: STM32F103CBT6
Footprint: Package_QFP:LQFP-48_7x7mm_P0.5mm
3D model: LQFP-48(7x7) (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`stm32f103cbt6.step`	617 KB	You want the bare part, or you mark your own boards.
`stm32f103cbt6-etched.step`	4.8 MB	You want the part with `STM32F103CBT6` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 1195 faces against 747 in the bare model. It survives export, section views, and rendering in any CAD tool, and it drops straight into KiCad or Fusion with no extra setup.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: STMicroelectronics datasheet (105 pp, sha256 ceab0f159ae79118, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF