120 MHz Cortex-M4 with 2 MB Flash — what it means for the BOM
The STM32L4S9ZIJ6TR is a 32-bit ARM Cortex-M4 MCU from STMicroelectronics, clocked at 120 MHz with 2 MB of Flash program memory and 640 KB of SRAM. It is part of the STM32L4 series, designed for low-power operation without sacrificing performance — the 120 MHz core and DSP instructions handle real-time control loops, sensor fusion, and audio processing in a single chip. The 112 I/O lines and rich peripheral set (CAN, USB OTG, multiple SPI/I²C/UART, plus an external bus interface) make it suitable for industrial control panels, motor drives, and IoT gateways where a BGA package is acceptable. The -40 to 85 °C temperature grade covers outdoor telecom cabinets and factory-floor enclosures, but not extended automotive under-hood or downhole environments.
Memory and peripheral density
Package and mounting
The 144-UFBGA (10x10 mm) package is a fine-pitch BGA — not hand-solder friendly. It requires a controlled reflow profile and X-ray inspection for void-free joints. The 112 I/O count demands a multi-layer PCB with via-in-pad or microvia routing. Plan for a dedicated ground plane and decoupling capacitor placement per ST's layout guidelines.
Sourcing and lifecycle
The STM32L4S9ZIJ6TR is listed as Active in production — no end-of-life notice or last-time-buy window is in effect. It is sourced through independent distribution and quoted to order against an RFQ; availability and current pricing are confirmed at quote time. For dual-sourcing resilience, ST offers pin-compatible density variants within the STM32L4 series, but no official second-source alternate from another manufacturer is recorded.