memory products - Al Kossow's Bitsavers

MK48Z08118/09119(B)-15/20/25FIGURE 7. POWER DOWN/POWER-UP TIMINGV". (MAX)- -V ... (MIN)- -VIO - -- ~t,.INT ~(MK48Z09119 ONLY) 1'-=-------f1lALL INPUTS RECOGNIZED DON'T CARE RECOGNIZEDALL VALID VALIDOUTPUTS (PER CONTROL INPUT) I}--------i f--HIGH.z---------(J (PER CONTROL INPUT)NOTE:Inputs mayor ml\X.Dot !2§ recognized at this time. Caution shouldbe taken to keep El or W In the high state or E2 tow as VCC risespast VpFD (min). Some systems may perform inadvertant,INritecycles after Vee rises but before normal system operation begins.Even though a power on reset Is being applied to the processora resa! cond~ion may not occur until alter the system clock Isrunning.Power Fall and Data RetentionWith Vee applied, the MK48Z08l18109J19 operatesas a static RAM. The Power-Fail Detect Circuit ofthe MK48Z08/18109J19 constantly monitors Vee.Because the reference voltage applied to the detectorlcomparatoris stabilized over temperature, thePower~Faii Detect trip pOint remains within theV PFD min/max window under all rated conditions.Once deselection has occurred, all inputs and outputsare "Don't Cares" alid may have anywherefrom -0.3 to 5.5 volts applied to them with absolutelyno effect upon the RAM.As Vee falls below approximately Vso volts, thepower switching circuit connects the lithium batteryto supply power to the RAM.The power switching circuit connects external Vecto the RAM and disconnects the battery when Veerises above approximately Vso volts. Normal RAMoperation can resume tREC after Vee reaches V PEQ(max). Caution should be taken to keep E 1, or Win the high state or E2 low as Vee rises past V PFD(min). Some systems may perform inadvertant writecycles after Vcc rises but before normal systemoperation begins.INTERRUPT FUNCTIONThe MK48Z09I19 provides a power-fail interrupt outputlabeled INT. The INT pin eliminates the needfor external power sensing components in applicationswhere an orderly shutdown of the system isnecessary: The INT pili is open drain for "wire or"applications and provides the user with 10 P.s to 40P.s advanced warning of an impending power-failwrite protect.7112319