BiCMOS sense amplifier having input waiting state

A sense amplifier comprising:

• a first input terminal for receiving a signal to be sensed;
• an output terminal for outputting a sensed signal;
• first and second power sources;
• a constant current source circuit connected between said first input terminal and said first power source;
• a first field effect transistor having a source-drain path connected between said first input terminal and said second power source;
• a first bipolar transistor having a base, collector, and emitter respectively connected to said first input terminal, said output terminal, and said second power source;
• a load element connected between said output terminal and said first power source;
• a second input terminal, connected to a gate of said first field effect transistor, for receiving a bias voltage for controlling said first bipolar transistor so that during an input waiting state a state immediately before or after said first bipolar transistor is turned on is set at said first input terminal;
• a first switching element having a collector-emitter path connected between said first power source and said output terminal and controlled to be set in an ON state upon output of the sensed signal from said output terminal;
• a second switching element having a source-drain path connected between said first input terminal and said second power source and controlled to be set in an ON state upon output of the sensed signal from said output terminal;
• and
• a p-n junction element connected in series with said second switching element.

A sense amplifier comprising:

• first and second sense amplifiers each having a first input terminal, an output terminal for a sensed signal, first and second power sources, a constant current source circuit connected between said first input terminal and said first power source, a field effect transistor having a source-drain path connected between said first input terminal and said second power source, an output bipolar transistor having a base, collector, and emitter respectively connected to said first input terminal, said output terminal, and said second power source, a load element connected between said output terminal and said first power source, and a second input terminal connected to a gate of said field effect transistor;
• first potential generating means for supplying to said first input terminal of said second sense amplifier a potential corresponding to a potential of said first input terminal of said first sense amplifier when said first sense amplifier is set in an input waiting state;
• and
• control means for controlling the potential at said output terminal of said second sense amplifier t a predetermined value.