50 MHz Cortex-M3 with on-chip Ethernet MAC
The LM3S6633-IQC50-A2: Its standout feature is an integrated Ethernet MAC, making it a single-chip solution for industrial gateways, protocol converters, and networked controllers that need a compact BOM without an external PHY interface chip. The 41 GPIOs and peripheral set — including I²C, SPI, UART, and PWM — cover the usual sensor and actuator interface needs in factory automation and building control panels.
Any new design should avoid this MCU unless it is a legacy-support or repair-only situation.
100-LQFP rework considerations
The exposed paddle is absent on this package, so the thermal mass is moderate — a 260°C peak reflow profile per J-STD-020 works, but the part is MSL 3 out of the bag; if the moisture-barrier bag has been open longer than the floor-life window, bake it at 125°C for 24 hours before rework to avoid popcorning.
Ethernet MAC integration — what it buys
The integrated Ethernet MAC with MII/RMII interface lets you connect an external PHY (e.g., a DP83848 or LAN8720) for 10/100 Mbps networking. This saves a separate MAC chip and keeps the board area tight for a two-layer PCB in a control panel. The 50 MHz core has enough headroom to run a lightweight TCP/IP stack (like lwIP) alongside the application code in the 128 KB Flash — budget about 40 KB for the stack, leaving 88 KB for the control logic.