The Texas Instruments LM3S6918-IBZ50-A2T is a 32-bit ARM Cortex-M3 microcontroller from the Stellaris® 6000 series, clocked at 50 MHz. It packs 256 KB of Flash program memory and 64 KB of SRAM, with an integrated Ethernet MAC and a full complement of serial interfaces — I²C, SPI, UART, IrDA, Microwire, and SSI. Eight 10-bit ADC channels and 38 GPIO lines round out the peripheral set. The part is specified over the -40°C to 85°C industrial temperature range and operates from a 2.25 V to 2.75 V supply. It comes in a 108-ball BGA package measuring 10x10 mm, making it a compact choice for networked control applications where board space is tight.
50 MHz Cortex-M3 — what it means for the control loop
At 50 MHz, this core executes single-cycle multiply and hardware divide, which translates to around 50 MIPS throughput. For a typical control loop reading an ADC, running a PID, and updating a PWM output, that leaves headroom for a lightweight TCP/IP stack on the Ethernet port. The 64 KB SRAM is enough to buffer a few Ethernet frames and hold a modest RTOS task list, but you will want to budget memory carefully if you are running a full web server or TLS.
108-BGA package — board design considerations
The 108-ball BGA measures 10x10 mm. The 38 GPIOs are distributed across the ball grid. Supply voltage is 2.25 V to 2.75 V.
Lifecycle status — obsolete, sourced through independent channels
Texas Instruments has marked the LM3S6918-IBZ50-A2T as obsolete. No last-time-buy window remains open. The part is available through independent distribution and surplus channels, sourced and quoted to order against an RFQ. For new designs, consider a current-production Stellaris or Tiva-C series part from TI — the LM3S6918's pin-compatible successors in the same family are the best starting point for a drop-in replacement, though you will need to verify exact peripheral and register compatibility against your firmware.