High-impedance IGFET input circuit suitable for smoke detector I.C.

An electronic system for maintaining a high impedance input for an integrated circuit by reducing leakage currents comprising:

• (a) a package including a plurality of conductive leads for conducting a plurality of electrical signals;
• and
• (b) an integated circuit mounted to said package, said integrated circuit including amplifier means having an input coupled to a first of said plurality of conductive leads for receiving a first electrical signal and having an output for providing a second electrical signal substantially equal to said first electrical signal, said output being coupled to a second of said plurality of conductive leads disposed in close proximity to said first conductive lead for reducing leakage currents.

An integrated circuit including an insulated-gate-field-effect-transistor and having a high impedance input comprising:

• (a) input terminal means for receiving an input voltage signal,
• (b) diode protection means coupled to said input terminal means for protecting the insulating layer of an insulated-gate-field-effect-transistor, and
• (c) amplifier means coupled to said diode protection means and responsive to the input voltage signal for generating an output voltage signal having a voltage substantially equal to the input voltage signal, wherein leakage current associated with said diode protection means is reduced.