Many NEC ASICs were based on standard 4000 series or 7400 series logic but internalized. By probing inputs and outputs with a logic probe or oscilloscope, you can deduce function. For example, Pin 5 might toggle every time you press "Power On" on the device – that is your standby control pin.
(Note: Always verify with the specific manufacturer datasheet for exact limits)
| Parameter | Symbol | Rating | Unit | | :--- | :---: | :---: | :---: | | Supply Voltage | $V_CC$ | 7.0 | V | | Output Voltage (Peak) | $V_OUT$ | 120 - 180 | V | | Operating Temperature | $T_opr$ | -20 to +70 | °C | | Storage Temperature | $T_stg$ | -40 to +125 | °C |
This site specializes in obsolete components. If NEC stopped making the B58944 in 1995, this is your best bet. nec b58944 datasheet Free
The IC works on a two-stage conversion principle:
The Short Answer: The B58944 is not a standard NEC semiconductor part number (like a microcontroller or transistor). It is almost certainly a custom OEM part number, likely a display (LCD) or a hybrid module from a specific device (e.g., a car stereo, cash register, or industrial equipment).
Because it's custom, NEC/Renesas will not have a public datasheet. You will need to search by application. Many NEC ASICs were based on standard 4000
Step-by-Step Search Strategy (Free):
Check Datasheet Archive & Utsource
Identify the Host Device (Most Effective) Check Datasheet Archive & Utsource
If It's an LCD (Likely)
Last Resort: Reverse Engineer
Important Warning: Avoid sketchy "free datasheet" sites that ask for a credit card or require you to download a .exe file. These are malware. Stick to the sites above.