K4E661612B Datasheet, PDF (9/36 Pages) Samsung semiconductor – 4M x 16bit CMOS Dynamic RAM with Extended Data Out

K4E661612B, K4E641612B
16. tCWL is specified from W falling edge to the earlier CAS rising edge.
17. tCSR is referenced to the earlier CAS falling edge before RAS transition low.
18. tCHR is referenced to the later CAS rising edge after RAS transition low.
RAS
LCAS
UCAS
tCSR
tCHR
CMOS DRAM
19. tDS is specified for the earlier CAS falling edge and tDH is specified by the later CAS falling edge in early write cycle.
LCAS
UCAS
DQ0 ~ DQ15
tDS
tDH
Din
20. tASC≥6ns, Assume tT = 2.0ns
21. If RAS goes high before CAS high going, the open circuit condition of the output is achieved by CAS high going. If CAS goes
high before RAS high going, the open circuit condition of the output is achieved by RAS high going.
22. If tRASS≥100us, then RAS precharge time must use tRPS instead of tRP.
23. For RAS-only refresh and burst CAS-before-RAS refresh mode, 4096(4K/8K) cycles of burst refresh must be executed within
64ms before and after self refresh, in order to meet refresh specification.
24. For distributed CAS-before-RAS with 15.6us interval CAS-before-RAS refresh should be executed with in 15.6us immediately
before and after self refresh in order to meet refresh specification.