| 摘要 |
<p>The DATA OUT circuit includes a multiplexer (11), a restore circuit (12), the combined sense amplifier and latching circuit (21) of the present invention and a standard output latch (15). The said combined sense amplifier and latching circuit (21) includes two latches (ML, SL) connected in series forming two stages in a master-slave like configuration. The first stage comprises the master latch (ML). It plays alternately the role of the sense amplifier and of the standard LSSD L1 latch. More specifically, the master latch (ML) is of the standard gated-loop type, formed by two cascaded inverters (I12, I13) with a first control device (TG4) in the loop. The second stage comprises the slave latch (SL), which is also a standard gated-loop latch formed by two cascaded inverters (I14, I15) with a second control device (P15) in the loop. The two latches are connected in series and isolated one from the other by a third control device (TG5). Typically, inverters are made by a pair of complementary FET devices connected in series. In the master latch (ML), the free ends of the PFET devices (P13, P14) are connected to a first supply voltage (Vdd), the free ends of the NFET devices (N4, N5) are dotted to form a common node (K) that is coupled to a reference voltage generator (23). Said reference voltage generator (23) allows said common node (K) to be connected either to a second supply voltage (the ground: GND) or to a reference voltage (VREF) lower than Vdd, instead of between said first and second supply voltages as in conventional sense amplifier latches. Control devices and the VREF generator are all driven by a single Set Sense Amplifier signal (SSA). In operation, both stages are alternatively selected by the SSA signal. As a result, when the SSA signal goes low, the master latch senses the selected bit line while the slave latch keeps the data previously sensed. When the SSA signal goes high, the new sensed data is latched into the master latch (which has become the +L1 LSSD latch), and is transferred through the slave latch (which is selected in driving mode) to the output terminal where the data out (DO) is available. The data remains valid in the master latch (ML) until the next SSA falling transition. In other words, one stage holds the previous data as long as the other one is working. In addition, a "Scan Data In" circuit (25) can be combined with the master latch (ML). Consequently, the combined sense amplifier and latching circuit (21) of the present invention which requires only one gating signal (SSA) for its operation, demonstrates significant growability and porosity capabilities. <IMAGE></p> |
