Nec B58944 Datasheet 2021 Jun 2026

When the chip's internal matrix degrades, the ECU struggles to load engine maps, throwing intermittent communication errors or resulting in a complete vehicle "No-Start" condition.

Frequently cross-referenced with the μPD43256BGU-70L , which is a 256 Kib Parallel SRAM.

The SOP-28 configuration generally follows standard JEDEC SRAM or driver layouts for 28-pin packages: Address Inputs: cap A sub 0 cap A sub 14 Control Pins: Chip Enable ( modified cap C cap E with bar above ), Output Enable ( modified cap O cap E with bar above ), and Write Enable ( modified cap W cap E with bar above cap V sub cap C cap C end-sub (Pin 28) and cap G cap N cap D www.dcddcc.com

Produced by NEC Corporation (now part of Renesas) and often branded under Bosch for automotive specific applications. nec b58944 datasheet 2021

It is frequently listed under (now largely associated with Renesas/Infineon legacy products) and is designed to manage power distribution within the complex circuitry of an ECU. Key Technical Characteristics Manufacturer: NEC (Legacy) Package: SOP-28 (Surface Mount Device - SMD) Application: Automotive ECU/Instrument Cluster Function: Dual-channel high-side controller/driver Pin Count: 28 NEC B58944 Applications in 2021

To summarize, the is a reference that no longer exists in official corporate archives. However, through careful reconstruction from real-world device testing, service manuals, and equivalent component data, one can safely utilize, test, and replace this transistor in legacy equipment.

The component acts as a high-reliability memory storage unit designed to sustain data processing during real-time engine operations. Specification Value NEC Electronics (Now Renesas Electronics) Standard Industry Equivalent μPD43256BGU-70L / μPD43256BGU-70Y Memory Capacity 256 Kibibits (32K x 8 bits) Memory Category Parallel Static RAM (SRAM) Package / Footprint Type SO-28 / SOP28 (Small Outline Package) Access Time 70 nanoseconds (ns) Package and Pin Configuration When the chip's internal matrix degrades, the ECU

Routes switched currents directly to external solenoids, injectors, or relays. High-current capacity with integrated flyback protection. Ties into the main PCB copper plane.

: Generates stable internal reference voltages to shield sensitive logic boards from vehicle voltage fluctuations.

: Limits power consumption when the vehicle is in an idle or standby state, protecting battery health. It is frequently listed under (now largely associated

However, it is critical to note that NEC's part numbering convention in that era often used "B" prefixes for PNP transistors and "D" for NPN. The "58944" suggests a custom or semi-custom OEM (Original Equipment Manufacturer) part number. Therefore, the search often leads to confusion, as no unified public datasheet exists under that exact string.

| Source | Notes | |--------|-------| | | Use search: B58944 (try quotes) | | Alldatasheet.com | Often has old NEC datasheets | | DatasheetArchive.com | Good for obsolete parts | | Mouser / DigiKey | Search B58944 — may show description | | NEC/Renesas customer support (legacy parts) | Provide full marking & package photo |

As electronic restoration gains popularity (vintage audio, retro computing, arcade machines), the demand for oddball parts like the NEC B58944 remains steady. Understanding its undocumented legacy is the key to successful troubleshooting.

Persistent corruption of temporary adaptation values, causing rough idling after ignition cycles.

| Dimension | Min | Max | |-----------|-----|-----| | Body Length | 10.0 | 10.5 | | Body Width | 4.4 | 4.7 | | Body Height | 15.0 | 15.9 | | Lead Pitch | 2.54 (nominal) | - | | Mounting Hole Dia | 3.6 | 3.8 |