80 MHz Cortex-M3 — throughput and memory budget
The LM3S5951-IBZ80-C3T runs an ARM Cortex-M3 core at 80 MHz — this is the instruction throughput ceiling for control loops, protocol stacks, and real-time data processing. The 256 KB on-chip flash and 64 KB SRAM provide the code and data space for a moderate-complexity firmware image; a typical HAL plus RTOS footprint leaves roughly 40–50 KB SRAM for application buffers and stacks. The core operates from a 1.08–1.32 V supply rail — a narrow window that demands a regulated source. A 1.2 V LDO with ±2 % accuracy keeps the core inside spec across load steps. The 16-channel 10-bit ADC samples analog inputs at up to 1 Msps; the conversion clock and sample time are configurable per channel.
Connectivity and peripheral set for industrial interfaces
This MCU integrates CAN, USB OTG, I²C, SPI, SSI, UART/USART, IrDA, LIN, Microwire, and QEI — a connectivity suite that targets industrial gateways, motor-control feedback paths, and multi-protocol sensor hubs. The 67 general-purpose I/O lines map to the 108-ball BGA footprint; the ball-out groups the high-speed serial interfaces on the package periphery to simplify PCB fan-out. On-chip peripherals include a brown-out reset, power-on reset, DMA controller, I²S audio interface, PWM timers, and a watchdog timer. The internal oscillator eliminates an external crystal for applications that tolerate ±1 % accuracy over temperature; for USB operation a 12 MHz external crystal is still recommended.
Obsolete — sourcing reality for BOM continuity
Texas Instruments has classified the LM3S5951-IBZ80-C3T as obsolete. The Stellaris family (Cortex-M3S 5000 series) has been phased out; no pin-compatible drop-in replacement exists from TI or a second-source vendor. Procurement must source this part through independent distribution and surplus inventory channels. The 108-ball BGA package (10×10 mm) is moisture-sensitive; bake and reball procedures follow the MSL label on each reel.
The 108-ball BGA (10×10 mm, 0.80 mm ball pitch) routes on a 4-layer board with via-in-pad or microvia fan-out under the centre balls. The core supply (1.08–1.32 V) and I/O supply (3.3 V typical) each need a dedicated power plane; the decoupling capacitor array sits within 5 mm of the BGA perimeter. The -40 to 85 °C industrial temperature grade covers factory-floor and outdoor enclosure environments without active cooling.