80 MHz ARM Cortex-M3 with USB OTG and dual CAN — what this part was designed for
The LM3S5791-IQC80-C0T: It was built for applications that need a mix of USB OTG connectivity, dual CANbus, LINbus, and a 16-channel 10-bit ADC — typical in industrial gateways, automotive body controllers, and building-automation panels where one chip handles both the control loop and the communication stack.
Any remaining stock in the channel is last-time-buy or surplus inventory. No guarantee of ongoing supply exists, so a pin-compatible drop-in would need evaluation for a redesign.
100-LQFP — rework and footprint notes
The exposed pad is not present on LQFP — all thermal dissipation goes through the leads, so keep the copper pour under the part solid and use via stitching to the ground plane. Will it survive the hot air? Yes, at 260 °C peak with a preheat to 150 °C — just don't dwell more than 10 seconds on any one side.
Supply and temperature grade
Core supply is 1.08 V to 1.32 V — a narrow window that needs a clean regulated rail, not a direct battery feed.