Early Electronic Calculator Hitachi HD3233 and Toshiba TM4312/TM4352/TM4356 Integrated Circuits

These ICs are commonly found as inverters and drivers in LSI calculators with vacuum fluorescent displays.

Period:	Used from (approx.) 1972 to 1976.
Source of Data:	Data for these devices was derived from reverse engineering of a Ricomac 1216, Miida MC840, Olympia CD401A, Sharp ELSI 804, etc.
Technology:	Probably just a PNP bipolar transistor for each inverter with all the emitters tied to GND.
Supply Voltage:	No direct connection of the supply voltage to the IC is required. However they were used in environments where the logic supply was -15V.
Logic:	Logic levels are GND and -15V. Outputs are open-collector. The TM4312 may have internal pull-down resistors on the bases while the others do not, although this has not been confirmed.
Packaging:	Standard 16-pin DIP.

Notes:	Although several of these devices have the same pinout there are differences between them. The HD3233 and TM4312 were used for logic-level inverters. The TM4352 tended to be used for drivers for vacuum fluorescent displays. Presumably the TM4352 has higher breakdown voltages to handle the approx. -50V display supply. Consequently, the HD3233 or TM4312 should not be used to replace the TM4352.
	IC packages as viewed from above.