120 MHz Cortex-M4 with 1 MB Flash — what it means for the design
The STM32L4R9ZGT6 is a 32-bit ARM Cortex-M4 microcontroller from STMicroelectronics, clocked at 120 MHz with 1 MB of Flash and 640 KB of SRAM. It sits in the STM32L4R series, ST's ultra-low-power line aimed at applications where active processing and standby current both matter — think battery-operated instrumentation, portable medical devices, or an HMI panel that needs to stay responsive while sipping power. The 112 I/O in a 144-LQFP package give it enough pinout for a parallel LCD interface plus a sensor array and a CANbus gateway without multiplexing.
Memory and peripheral budget
1 MB of Flash is enough for a moderate GUI stack with a real-time OS kernel and application code. The 640 KB SRAM handles frame buffers for a small TFT display without external memory. On the connectivity side, the part carries CANbus, USB OTG, and an external bus interface (EBI/EMI) for expanding memory or attaching an FPGA. The 16-channel 12-bit ADC and dual 12-bit DAC cover analog front-end tasks like battery monitoring or sensor conditioning.
Supply range and temperature grade
The supply range from 1.71 V to 3.6 V lets this MCU run directly from two alkaline cells or a single Li-ion cell without a boost converter. The -40°C to 85°C industrial temperature grade covers outdoor telecom enclosures and factory-floor controllers. Brown-out detect and POR are integrated, so external supervisory circuits are optional.
Lifecycle and sourcing posture
The STM32L4R9ZGT6 is classified as end-of-life (EOL) by the manufacturer. For existing BOM lines, this part is sourced through independent distribution channels and quoted to order against an RFQ.