1 - Al Kossow's Bitsavers

TMS4500ADYNAMIC RAM CONTROLLERarbiterThe arbiter provides two operational cycles: access and refresh. The arbiter resolves conflicts between cycle requestsand cycles in execution, and schedules the inhibited cycle when used in cycle·steal mode.timing and control blockThe timing and control block executes the operational cycle at the request of the arbiter. It provides the DRAM arraywith RAS and CAS signals. It provides the CPU with a ROY signal. It controls the multiplexer during all cycles. Itresets the refresh rate generator and decrements the refresh counter during refresh cycles.absolute maximum ratings over operating ambient temperature range (unless otherwise noted) tSupply voltage range, VCC (see Note 1) ......................................... -1.5 V to 7 VInput voltage range (any input) (see Note 1) .....................................• -1.5 V to 7 VContinuous power dissipation ............................................... __ . _ _ _ 1_2 WOperating ambient temperature range .......... ___ . __ ........ _.. __ . _ . __ .. ____ . _. O°C to 70°CStorage temperature range .. ________ .... __ . __ ... __ .. ___ . _..... _ . _ • __ . __ . _ _ -65°C to 150°Crecommended operating conditionsPARAMETER MIN NOM MAX UNITSupply voltage, Vee 4.5 5 5.5 VHigh-level input voltage, VIH 2.4 6 Vlow-level input voltage, Vil -1 + 0.8 VOperating ambient t temperature, T A 0 70 °et Stres&es beyond those listed under" Absolute Maximum Ratings" may cause permanent damage to the device. This is stress rating only and functionaloperation of the device at these or any other conditions beyond those indicated in the "Recommended Operating Conditions" section of this specificationis not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.t The algebraic convention, vyhere the more negative limit is designated as minimum, is used in this data sheet for logic voltage levels only.NOTE 1: Voltage values are with respect to the ground terminal.electrical characteristics over recommended operating ambient temperature range (unless otherwise noted)PARAMETER TEST CONDITIONS MIN Typt MAX UNITV OHMAO-MA7, ROY 2.4High-levelIOH = -.1 mA Vee = 4.5 VRASO,RAS1,eAS2.7output voltageREFREQ IOH = 100 ",A Vee = 4.5 V 2.4V~OL low-level output voltage IOl = 4 mA Vee = 4.5 V 0.4 VIIHHigh-level REFREQ 100VI = 5.5 Vinput current All others10",AIIIlow-level REFREQ -1.25 mAVI = OVinput current All others-10 p.AIOZ Off-state output current V O =Ot04.5V Vee = 5.5 V ±50 ",Alee Operating supply current TA = oDe 100 140 mAe i Input capacitance VI = OV, f = 1 MHz 5 pFeo Output capacitance Vo = 0 V, f = 1 MHz 6 pF+oJ..oc.C.::::Jen~oEQ):E"CCCO:Ecd:a:to)"eCOc>ot All typical values are at VCC = 5 V, T A = 25 DC except where otherwise noted.184TEXAS (NSTRUMENTS4-129INCORPORATED