LMC1992 Digitally-Controlled Stereo Tone and Volume Circuit with Four-Channel Input-Selector by National Semiconductor. Package: 28-pin (wide) DIP A used in many early home computers such as Atari 520 and 1040 STE and Megga STE. Download National Semiconductor LMC1992 datasheet: Status: NOS (New Old Stock) RoHS compliant: no