FRAM-based 16-bit MCU for low-power control
Its distinguishing feature is 4 KB of FRAM program memory — non-volatile storage that writes at near-SRAM speed with essentially unlimited endurance, unlike conventional Flash. This makes it a strong fit for applications that log data, update firmware in the field, or need to retain state across power cycles without an external EEPROM. The device integrates 1 KB of SRAM, 30 general-purpose I/O lines, a 14-channel 10-bit ADC, and serial interfaces including I²C, SPI, and UART.
FRAM vs Flash — what it changes for the BOM
The 4 KB FRAM array is byte-addressable and writes at bus speed with no erase cycle, so the firmware can treat it as unified memory for code and data. This simplifies the memory map and reduces the component count on the board. The trade-off is that FRAM density typically tops out lower than Flash — the MSP430FR5721IDA offers 4 KB, which constrains the firmware footprint compared to a Flash MCU with 16 KB or 32 KB. For applications that fit within that limit, the FRAM approach saves a serial memory device and its associated PCB area.
Package and thermal considerations for layout
The device is supplied in a 38-pin TSSOP package (6.10 mm body width) with a 0.5 mm pitch. It is a surface-mount part intended for reflow soldering. The package does not have an exposed thermal pad, so heat dissipation relies on the leadframe and PCB copper. Decoupling with a 0.1 µF ceramic capacitor per supply pin pair is sufficient for this speed grade.