HYB18T256400AF Datasheet, PDF (83/90 Pages) Infineon Technologies AG – 256 Mbi t DDR2 SDRAM

HYB18T256400/800/160AF
256Mb DDR2 SDRAM
8.3.3 Slew Rate Definition for Input and Data Setup and Hold Times
Setup (tIS & tDS) nominal slew rate for a rising signal is defined as the slew rate between the last crossing of
VREF(dc) and the first crossing of VIH(ac)min. Setup (tIS & tDS) nominal slew rate for a falling signal is defined as
the slew rate between the last crossing of VREF(dc) and the first crossing of VIL(ac)max. If the actual signal is
always earlier than the nominal slew rate line between shaded ‘VREF(dc) to ac region’, use nominal slew rate for
derating value (see fig. A). If the actual signal is later than the nominal slew rate line anywhere between shaded
‘VREF(dc) to ac region’, the slew rate of a tangent line to the actual signal from the ac level to dc level is used for
derating value.(see fig.B)
Hold (tIH & tDH) nominal slew rate for a rising signal is defined as the slew rate between the last crossing of
VIL(dc)max and the first crossing of VREF(dc). Hold (tIH & tDH) nominal slew rate for a falling signal is defined as
the slew rate between the last crossing of VIH(dc)min and the first crossing of VREF(dc). If the actual signal is
always later than the nominal slew rate line between shaded ‘dc to VREF region’, use nominal slew rate for derat-
ing value (see fig. A). If the actual signal is earlier than the nominal slew rate line anywhere between shaded ‘dc to
VREF(dc) region’, the slew rate of a tangent line to the actual signal from the dc level to VREF level is used for
derating value (see fig.B).
CK, CK for tIS and tIH
DQS, DQS for tDS and tDH
t_IS
tDS
ttDIHH
VREF to ac
region
dc to VREF
region
dc to VREF
region
VREF to ac
region
tIS
tDS
tIH
tDH
V_DDQ
V_IH(ac)min
V_IH(dc)min
V_REF
V_IL(dc) max
V_IL(ac) max
V_SS
Delta TFS
Delta TRH Delta TRS Delta TFH
VIRLE(dFc()dmc)ax- V- IVLI(La(ca)cm)maxax
Setup Slew Rate =
Delta TFS
VIH(adc)min - VIRLE(aFc()dmc)in
Setup Slew Rate =
Delta TRS
falling signal
rising signal
VREF(-dcV)IL-(VdIcL)(mdac)xmax
Hold Slew Rate =
Delta TRH
VIH(dc)min - VREF(dc)
Hold Slew Rate =
Delta TFH
fig. A
rising signal
falling signal
CK, CK for tIS and tIH
DQS, DQS for tDS and tDH
VREF to ac
region
dc to Vref
region
dc to Vref
region
VREF to ac
region
ttDISS
tt_DIHH
ttDISS ttDIHH
V_DDQ
V_IH(ac)min
V_IH(dc)min
V_REF
V_IL(dc) max
V_IL(ac) max
V_SS
Delta TFS
tangent line
nominal line
Delta TRH Delta TRS Delta TFH
tangent line [VREF(dc) - VIL(ac)max]
Setup Slew Rate =
Delta TFS
tangent line [VIH(ac)min - VREF(dc)]
Setup Slew Rate =
Delta TRS
falling
signal
rising
signal
tangent line [VREF(dc) - VIL(dc)max]
Hold Slew Rate =
Delta TRH
tangent line [VIH(dc)min - VREF(dc)]
Hold Slew Rate =
Delta TFH
fig. B
rising
signal
falling
signal
Page 83
Rev. 1.02 May 2004
INFINEON Technologies