Early Electronic Calculator Sony 500 Series Integrated Circuits

Known Devices:	501, 502, 503, 504.
Period:	Late 1960s.
Source of Data:	Data for these devices was derived from reverse engineering of a Sony SOBAX 2500 (1999 Nov).
Technology:	Measurements suggest DTL/TTL with open-collector outputs. Given the low supply voltage though, this is not standard DTL/TTL. Although the outputs appear to be open-collector, there are no pull-up resistors used with these ICs.
Supply Voltage:	+4 V.
Logic:	Gate symbols are presented in accordance with TRUE = high impedance or +4V FALSE = low impedance to ground or 0V
Packaging:	Sony 14-pin DIP. Similar to standard DIP but the distance between the two rows is slightly greater than the standard (...one can only wonder).

Notes:	The flip-flops in this logic family are Master/Slave JK flip-flops with the clocks for the master and slave sections kept separate. ΦC = Capture Input (Master section clock) ΦT = Transition Input (Slave section clock) The state of the J/K inputs is captured when ΦC is TRUE and ΦT is FALSE. The Q and not-Q outputs are set in accordance with the captured state when ΦT goes TRUE. See the comments on the similar JMOS clocking scheme.
	It appears these ICs can develop open inputs. In some instances these open connections may be repaired by heating the input pin with a soldering iron for 10 to 20 seconds. This observation is based on experience with two Sony SOBAX 2500 calculators. See repair notes for SOBAX 2500 calculators.
	IC packages as viewed from above.