If the NEC B58944 dissipates 20W and RθJC is 2°C/W, the case will be 40°C above the junction. You need a heatsink with thermal resistance (RθSA) low enough to keep Tc < max rating.
Look through the Renesas electronics archive using the base part number.
NEC D43256BGU-70Y (often labelled as B58944 on the board). Function: Fast CMOS Static RAM (SRAM). Capacity: 256 K-bits (32 KiloBytes). Package: SOP-28 / TSOP-28 (Surface Mount). Access Time: 70 ns (indicated by -70Y). Usage: Automotive Engine Computer Boards (ECU). 2. Why is the NEC B58944 Chip Getting "Hot"? nec b58944 datasheet hot
It handles temporary variables such as fuel trim values, sensor readings, and ignition timing adjustments that require high-speed read/write access.
| Source | Brand / Manufacturer Listed | Key Description / Notes | | :--- | :--- | :--- | | | NEC | Auto-specific supplier; lists it for various Bosch ECUs. | | Utsource.net | Infineon | Describes it as an LDO voltage regulator in SOP-28 package. | | 114ic.com | Not Listed | A sourcing marketplace with multiple suppliers. | | Elparts.mekweb.eu | NEC | Notes it as an SRAM with 256 Kib size. | | Buy360.com.tw | NEC | Identifies it as a BOSCH vehicle computer driving chip. | If the NEC B58944 dissipates 20W and RθJC
: When soldering the replacement IC back onto the board, ensure the center belly pads or ground pin groupings are thoroughly wetted with solder. Adding a small, dedicated automotive-grade thermal pad on top of the package can help transfer heat to the outer metal ECU housing, keeping it from running critically hot in the future. The specific Bosch or factory ECU part number . The OBD-II error codes or symptoms you are experiencing.
In conclusion, the NEC B58944 datasheet provides a comprehensive overview of the component's specifications, features, and characteristics. This popular hot device is widely used in various applications, including industrial control systems, medical devices, consumer electronics, and automotive systems. Its high reliability, low power consumption, compact design, and high contact rating make it a preferred choice among engineers and designers. By understanding the technical details of the NEC B58944, designers and engineers can make informed decisions when selecting components for their projects. NEC D43256BGU-70Y (often labelled as B58944 on the board)
If you are seeing this hot chip, it's a clear sign the to avoid complete failure.
The first thing one notices upon opening the B58944 datasheet is the sheer density of information. Unlike modern, web-based documentation that often relies on interactive diagrams and simplified tooltips, the B58944 datasheet is linear, exhaustive, and unapologetically technical.