2021 | Nec B58944 Datasheet
While many legacy NEC semiconductor documents date back to earlier decades (such as general power transistor sheets from 2002), the B58944 remains a relevant part in the automotive repair industry as of 2021 and beyond for maintaining older vehicle fleets. Key Technical Specifications
The is a specialized integrated circuit (IC) primarily utilized as an ECU driver within automotive engine management systems. It is technically equivalent to the $\mu$PD43256BGU-70Y , a 256 Kib Parallel SRAM. Technical Overview and Specifications
(indicated by the "-70" suffix in the equivalent part number). Applications and Use Cases Automotive ECU Repair : The B58944 is a common component in BOSCH automotive engine computers
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Engine control unit (ECU) repair, specifically as a drive chip for automotive computers. nec b58944 datasheet 2021
If you have the component and cannot find a datasheet:
Yes. In most Bosch ECUs, injector calibrations are stored inside the B58944’s memory. After transferring the chip, using a diagnostic tool such as CanClip , AutoCOM , or the manufacturer’s software [16†L21-L24][2†L16-L18].
In practice, the B58944 is often paired with a specific bootloader and firmware that expects the 70‑ns access time and the specific power‑up sequence of the μPD43256 family. Using a general‑purpose SRAM (e.g., an AS6C62256) is risky and may lead to sporadic faults. The safest course is to obtain a genuine NEC B58944 or a pre‑programmed pull from a known‑good ECU.
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 While many legacy NEC semiconductor documents date back
Hosts active fuel-trim corrections and ignition timing modifications calculated on the fly.
If you share the , pin count , and surrounding circuit (power supply, MCU, opto, etc.), I can likely identify the real NEC part family and point you to the correct datasheet.
The component acts as an auxiliary operational memory buffer.
The vehicle completely forgets idle-air adaptations, fuel trim corrections, and transmission shift behaviors every time the key is turned off. If you share with third parties, their policies apply
The B58944 provides two independent high-side switches in a single 28-pin package. This allows it to control two separate high-power loads (e.g., two injectors or two solenoids) while saving board space compared to using separate driver circuits. 2. Robust Automotive Design
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Values derived from standard operating conditions at $T_a = 25^\circ C$ unless otherwise noted.