NEC Corporation (now part of Renesas Electronics). Package Type: SOP-28 (Small Outline Package with 28 pins).
The datasheet includes graphs showing the relationship between collector current and intensity. For engineers designing modifications, the graph is essential for high-frequency tuning. Common Applications The NEC B58944 was a "workhorse" component found in:
| 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 | – | nec b58944 datasheet
Since no official NEC B58944 datasheet is publicly archived, the following parameters are derived from NEC’s standard hybrid regulator family (e.g., µPC7800 series and µPC2930 series). Use these values only as a reference for testing or substitution:
Because these chips are prone to damage from voltage spikes or age-related failure in ECUs, they are widely sought as replacement parts for ECU board repairs. Blank State: NEC Corporation (now part of Renesas Electronics)
Ensure the replacement can handle the same fTf sub cap T if used in a radio or data circuit. Conclusion
The B58944 is a frequent "point of failure" in aging automotive hardware. Because it handles critical data streams within the ECU, a malfunction can lead to severe engine performance issues, "no-start" conditions, or communication errors with diagnostic tools. Blank State: Ensure the replacement can handle the
Pin 1 may be identified by a chamfered edge or dot on the package. Always verify with a multimeter before applying power.