| 摘要 |
PURPOSE:To give the sample holding function to the sense amplifier by providing the constant current switch to the constant current source of the sense amplifier, and also to ensure draw-out the steady comparison output in a high speed. CONSTITUTION:The sense amplifier comprises transistors TrQ1-Q4 plus resistance R1 and R2. TrQ5 and Q6 form a differential switch, and TrQ7 functions as the current source for TrQ3 and Q4. When sampling pulse SP is applied to TrQ5, TrQ5 is turned on with TrQ6 turned off respectively. Here bias voltage V2 and resistance R3 of TrQ7 are decided so as to satisfy the reversing conditions of the memory, and thus the output voltage becomes V<+>-R.Is (Is: current flowing to TrQ8). While no sampling pulse is applied, TrQ5 is turnned off with TrQ6 turned on each, and the output voltage features V<+>-R1.Is. As a result, the current flowing to resistance R1 and R2 becomes constant regardless of the presence or absence of the sampling pulse, also ensuring the constant comparizon output. |
