Patent ID: 7098438

Claim:
An apparatus comprising a latch circuit which includes: first and second resonant tunneling devices coupled in series with each other between first and second nodes; and a reset portion coupled to said first and second nodes, said reset portion including a photodiode portion which is responsive to varying photonic energy for switching between first and second states which are different, wherein when said photodiode portion is in said first state said reset portion normalizes a voltage across each of said resonant tunneling devices; wherein said first and second resonant tunneling devices are resonant tunneling diodes which are substantially identical to each other; wherein said photodiode portion includes a photodiode coupled between said first and second nodes, said photodiode being conductive in said first state of said photodiode portion, and being substantially nonconductive in said second state of said photodiode portion; a first terminal to which is applied a first voltage, and a second terminal to which is applied a second voltage less than said first voltage; and wherein said reset portion includes a first resistive element coupled between said first terminal and a first end of said photodiode, a first capacitive element coupled between said first node and said first end of said photodiode, a second resistive element coupled between said second terminal and a second end of said photodiode, and a second capacitive element coupled between said second node and said second end of said photodiode.