Nec B58944 Datasheet _best_ Jun 2026

At its core, the is a surface-mount, high-speed, 256K-bit CMOS static RAM (SRAM) device. It's specifically designed to operate within the demanding environment of a vehicle's electronic systems. The common full part number is D43256BGU-70Y , with "B58944" being a factory marking code printed on the chip's body.

Replacing the NEC B58944 requires proper surface mount repair tools to prevent delaminating the delicate multi-layer PCB traces found inside automotive ECUs. Step-by-Step Replacement Process

Tell me whether you have a scanned PDF or a photo of the part marking, or confirm the exact package and full part code. I can then locate the precise datasheet numbers (pinout tables, absolute max values, detailed electrical characteristics) and produce a component-specific summary, BOM notes, and recommended schematic snippets.

| Parameter | Min | Typical | Max | Unit | Condition | |-------------------------|-----|---------|-----|------|--------------------------| | Input Voltage (VIN) | 7 | 12 | 35 | V | – | | Output Voltage (VOUT) | 4.75| 5.0 | 5.25| V | IOUT ≤ 500mA | | Output Current | – | 500 | 1000| mA | With heatsink | | Dropout Voltage | – | 2.0 | 2.5 | V | IOUT = 500mA | | Line Regulation | – | 0.1 | 0.5 | % | VIN from 8V to 30V | | Load Regulation | – | 0.5 | 1.0 | % | IOUT from 10mA to 500mA | | Quiescent Current | – | 5 | 10 | mA | No load | | Ripple Rejection | 55 | 65 | – | dB | f = 120Hz | | Operating Temperature | -20 | 25 | 85 | °C | – | | Storage Temperature | -40 | – | 125 | °C | – |

. It is a "workhorse" component within BOSCH ECU architectures. Technicians often look for this specific datasheet when troubleshooting: Engine Computer Failures: nec b58944 datasheet

Probe the PCB:

The NEC B58944 is engineered to withstand the extreme environmental conditions of an engine bay, including high thermal cycles, voltage spikes, and mechanical vibration. Core Architecture and Specifications : NEC (Nippon Electric Company)

: Random loss of vehicle map configurations or immoblizer data syncing. Bench Testing Protocol

: The 70 ns access time ensures the ECU can make micro-second adjustments to engine parameters based on sensor input. Микросхема NEC B58944 D43256BGU-70Y At its core, the is a surface-mount, high-speed,

Search for on a SMD code website (e.g., smd.yooneed.one or markingcodes.com ). But since that specific 5-digit number is unusual, try this instead:

NEC Corporation (now part of Renesas Electronics). Package Type: SOP-28 (Small Outline Package with 28 pins). Compliance: Lead-free and RoHS compliant.

Practical summary for repair/modification

If you are performing a repair on an ECU, keep these factors in mind: Replacing the NEC B58944 requires proper surface mount

Ensure you are using the SOP-28 variant, as 256K SRAMs also exist in DIP (Dual Inline Package) formats which will not fit the PCB footprints of modern ECUs.

(Engine Control Unit) boards, this specialized integrated circuit (IC) is a critical component for engine management systems.

If you are in the business of automotive repair or specialized electronics, you have likely encountered the . Often referred to by its equivalent part number, μPD43256BGU-70L , this integrated circuit (IC) is a staple in high-performance Engine Control Units (ECUs), particularly those manufactured by Bosch .

To safely integrate or substitute this component, engineering logic dictates adherence to the operational limits specified in the manufacturer's reference datasheet: : 256 Kibit (