108-ball BGA — PCB layout and rework considerations
The LM3S1B21-IBZ80-C5T: Housed in a 108-ball LFBGA (10x10 mm body), this MCU demands a multi-layer PCB for fan-out — the 0.50 mm ball pitch routes out to inner layers on a 4-layer board; two-layer designs will struggle to escape the inner rows without blind vias.
Industrial temperature grade and peripheral set
On-chip peripherals include an 8-channel 10-bit ADC, brown-out detect, DMA, PWM, and a watchdog timer — enough for a sensor-fusion node or a motor-control loop without external ADC or supervisor ICs. Connectivity covers EBI/EMI, I²C, SPI, SSI, UART/USART, IrDA, LIN, and Microwire — the EBI/EMI interface allows glueless connection to external SRAM or NOR flash if the on-chip 256 KB is insufficient.
No pin-compatible direct replacement exists from TI — any functional substitute requires a board spin and firmware port.