1 - Al Kossow's Bitsavers

TMS4257262.144·8IT DYNAMIC RANDOM·ACCESS MEMORIESNIBBLE MODE CYCLEswitching characteristics over recommended supply voltage range and operating free-air temperature range(unless otherwise noted)ALT. TMS4257-10 TMS4257-12PARAMETERSYMBOL MIN MAX MIN MAXta(CN) Nibble mode access time fro~ CAS tNCAC 25 30UNITnsPARAMETERNibble mode access time from CAS'ALT.SYMBOLtNCACtiming requirements over recommended supply voltage range and operating free-air temperature range(unless otherwise noted)PARAMETERALT. TMS4257-10 TMS4257-12SYMBOL MIN MAX MIN MAXtc(N) Nibble mode cycle time tNC 50 60tc(rdWN) Nibble mode read-modify-write cycle time tNRMW 70 85tCLRHN Nibble mode delay time, CAS low to RAS high tNRSH 25 30tCLWLN Nibble mode delay time, CAS to W delay tNCWD 20 25tw(CLN) Nibble mode pulse duration, CAS low tNCAS 25 30tw(CHN) Nibble mode pulse duration, CAS high tNCP 15 20Nibble mode write command setuptsu(WCHN)time before CAS hightNCWL '20 25timing requirements over recommended supply voltage range and operating free-air temperature range(unless otherwise noted)PARAMETERALT. TMS4257-15 TMS4257-20SYMBOL MIN MAX MIN MAXtc(N) Nibble mode cycle time tNC 75 90tc(rdWN) Nibble mode read-modify-write cycle time tNRMW 105 130tCLRHN Nibble mode delay time, CAS low to RAS high tNRSH 40 50tCLWLN Nibble mode delay time, CAS to W delay tNCWD 30 40tw(CLN) Nibble mode pulse duration, CAS low tNCAS 40 50tw(CHN) Nibble mode pulse duration, CAS high tNCP 25 30Nibble mode write command setuptsu(WCHN)time before CAS hightNCWL 35 45UNITnsUNITnsenCI)CJ'S;CI)C...oc.C.:J(/)..>oECI)~"'CCCO~«a:CJ'ECOc>CTEXASINSTRUMENTSPOST OFFICE BOX 225012 • DALLAS. TEXAS 752654-71