50 MHz Cortex-M3 with integrated Ethernet — what it means for the BOM
The LM3S6911-IQC50-A2T: The 64 KB RAM is the number to watch: after the TCP/IP stack, Ethernet buffers, and RTOS kernel footprint, the remaining heap for the application is typically 20–30 KB — enough for a lightweight web server or Modbus TCP gateway, but tight for a full TLS handshake without external RAM. This saves roughly 30–40 mm² of board area and about $1.50–$2.00 in BOM cost at volume, though the PHY's power consumption (typically 150–200 mW active) must be budgeted in the system thermal envelope.
The 100-LQFP package (14x14 mm, 0.5 mm pitch) is hand-solderable and inspectable — no X-ray needed. A 4-layer PCB with a solid ground plane under the QFP is sufficient for signal integrity on the Ethernet differential pairs.
Lifecycle and sourcing posture
The base product number LM3S6911 covers multiple temperature and package variants. If the -IQC50-A2T suffix (industrial temp, 50 MHz, tape-and-reel) is the specific BOM line, the tray-pack version (LM3S6911-IQC50-A2) is the drop-in alternative for hand-assembly or low-volume builds — same die, same electricals, different shipping media.