EM47FM0888MBA

Jul. 2012

10/38

www.eorex.com

Note that while Address/command and DQ signal requirements are with respect to VREF, the single-ended

components of differential signals have a requirement with respect to VDD/2; this is nominally the same.

The transition of single-ended signals through the AC-levels is used to measure setup time. For singleended

components of differential signals the requirement to reach VSEL max, VSEH min has no bearing on timing, but

adds a restriction on the common mode characteristics of these signals.

Single-ended levels for CK, DQS, /CK, /DQS

Symbol

Min.

Max.

Units

Note

Parameter

Single-ended high-level for strobes

(VDD/2)+0.175

See Note3

V

1,2

VSEH

(VDD/2)+0.175

See Note3

V

1,2

Single-ended high-level for CK, /CK

Single-ended low-level for strobes

See Note3

(VDD/2)-0.175

V

1,2

VSEL

Single-ended low-level for CK, /CK

See Note3

(VDD/2)-0.175

V

1,2

Note1.

For CK, /CK use VIH/VIL(AC) of address/command; for strobes (DQS, DQS) use VIH/VIL(AC) of DQs.

Note2.

VIH(AC)/VIL(AC) for DQs is based on VREFDQ; VIH(AC)/VIL(AC) for address/command is based on

VREFCA; if a reduced AC-high or AC-low level is used for a signal group, then the reduced level

applies also here.

Note3.

These values are not defined, however the single-ended components of differential signals CK, /CK,

DQS, /DQS need to be within the respective limits (VIH(DC) max, VIL(DC) min) for single-ended signals

as well as the limitations for overshoot and undershoot.