This chip acts as a temporary, high-speed data storage for the main microcontroller in an ECU. When your engine runs, data is constantly in flux—air-fuel ratios, ignition timing, sensor inputs—and the B58944 is where this critical, ever-changing data is held for immediate processing.

Have you encountered the NEC B58944 in a device? Contribute your findings to the comments section or contact the author for inclusion in future updates to this datasheet guide.

| Parameter | Symbol | Typical Value | Unit | Test Conditions | | :--- | :---: | :---: | :---: | :--- | | Turn-on Time | $t_on$ | 0.7 | $\mu s$ | $I_C = 4A, I_B1 = 0.8A$ | | Storage Time | $t_stg$ | 4.0 | $\mu s$ | $I_C = 4A, I_B1 = 0.8A$ | | Fall Time | $t_f$ | 0.4 | $\mu s$ | $I_C = 4A, I_B1 = 0.8A$ |

| Supplier | Part Number Offered | Additional Notes | | :--- | :--- | :--- | | | B58944 | Lists as Infineon; verify specs | | Centralitas Ecu | Circuito integrado B58944 | Verified automotive ECU supplier | | Buy360 | NEC B58944 D43256BGU-70Y | Includes Bosch body computer IC | | Mekweb (Elparts) | μPD43256BGU-70L | NEC Electronics, SO-28 package | | Win-Source | UPD43256BGU-70Y-E2 | Renesas Electronics |

If the B58944 is a switching regulator (e.g., similar to NEC µPC494 PWM controller), then specifications would differ drastically – switching frequency ~40kHz, output current up to 3A external transistor.

If you are currently troubleshooting an automotive board, what specific or symptoms is the engine module displaying? I can provide guided diagnostic steps to isolate the issue to this specific memory chip. Share public link

The is an integrated circuit primarily used as a static random-access memory (SRAM) chip in automotive Engine Control Units (ECUs). It is commonly found in Bosch-manufactured ECUs for vehicles like Honda, Iveco, and various European models. Technical Specifications

This IC is a high-failure component in BOSCH automotive ECUs. Technicians often seek the for:

Technically, the B58944 is an chip. It is frequently identified as an automotive-grade equivalent or a rebranded version of the μPD43256BGU-70L . Capacity: 256 Kib (32K x 8 bits).

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– Many NEC monitors (e.g., Multisync series) used 7-pin SIP ICs for H-out or V-out pre-drivers. The B58944 could be a replacement for defective vertical output ICs like LA7830 or TDA1170.

The is a high-density semiconductor component, frequently identified by its equivalent part number, μPD43256BGU-70L . In technical terms, it is a Static Random Access Memory (SRAM) chip organized with a capacity of 256 Kilobits (32K x 8 bits) .