48 MHz RX core in a 7x7 mm QFN
The R5F51403AGNE#30 is a 32-bit single-core RX microcontroller from the RX140 series, clocked at 48 MHz. It packs 64 KB of flash and 16 KB of RAM into a 48-HWQFN package with a 7x7 mm footprint and an exposed thermal pad. The 48 MHz clock is the ceiling for instruction-fetch cycles from flash; the RX core's single-cycle multiply-accumulate unit keeps real-time control loops deterministic without wait-state jitter at that speed.
Supply, temperature, and board integration
The 48-HWQFN package requires a thermal-via array under the exposed pad to pull heat into the ground plane. The 0.5 mm pitch demands a four-layer board for reliable fan-out of the 39 I/O — two-layer break-out is possible but risks signal-integrity issues on the outer rows.
On-chip peripherals and sensor interface
Eleven 12-bit ADC channels give this part enough analog front-end for a three-phase motor current-sense plus a thermistor or two, all sampled sequentially through the scan list. The DMA controller can shuttle conversion results to RAM without CPU intervention — the core stays free for the control loop. Serial connectivity covers I²C, SCI (UART), and SPI — enough to talk to an external EEPROM, a hall-effect current sensor over SPI, and a Modbus RTU link over SCI simultaneously. The 4 KB of data flash (EEPROM emulation) stores calibration coefficients and fault logs with 100,000 write-cycle endurance.