The LM3S6100-IBZ25-A2T is a 32-bit ARM Cortex-M3 microcontroller from the Stellaris® 6000 series, built around a 25 MHz core with 64 KB of Flash and 16 KB of RAM. The part also carries UART, SPI, SSI, and IrDA interfaces, plus a PWM unit and watchdog timer, so it can handle local sensor readout and actuation alongside the network stack. Rated for -40 to 85 °C and supplied at 2.25 V to 2.75 V, it suits factory-floor cabinets, outdoor telecom shelters, and other environments where extended temperature and a single low-voltage rail are the norm. The 108-ball BGA package (10x10 mm) means the board needs a reflow profile and via-in-pad capability — this is not a hand-solderable part.
Texas Instruments has marked the LM3S6100-IBZ25-A2T as obsolete. For an existing design that already qualifies this MCU, the only sourcing path is the independent surplus and broker channel. If you are qualifying a new build, the Stellaris family has been superseded by TI's Tiva C Series and later Cortex-M4F parts. Those are not pin-compatible, so a board respin is required. For a legacy BOM line that must stay on this exact footprint, the broker channel is the realistic option.
The 25 MHz Cortex-M3 runs a lightweight TCP/IP stack alongside a control loop polling sensors over SPI or UART.