1 differential signals definition, Differential signals definition, Differential swing requirement for clock (ck – Samsung M391B5773DH0 User Manual

Page 15: Datasheet, Ddr3l sdram, Unbuffered dimm

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- 15 -

datasheet

DDR3L SDRAM

Rev. 1.0

Unbuffered DIMM

11.3 AC and DC Logic Input Levels for Differential Signals

11.3.1 Differential Signals Definition

Figure 3. Definition of differential ac-swing and "time above ac level" tDVAC

11.3.2 Differential Swing Requirement for Clock (CK - CK) and Strobe (DQS - DQS)

NOTE :
1. Used to define a differential signal slew-rate.
2. for CK - CK use V

IH

/V

IL

(AC) of ADD/CMD and V

REFCA

; for DQS - DQS use V

IH

/V

IL

(AC) of DQs and V

REFDQ

; if a reduced ac-high or ac-low level is used for a signal group,

then the reduced level applies also here.

3. These values are not defined, however they single-ended signals CK, CK, DQS, DQS need to be within the respective limits (V

IH

(DC) max, V

IL

(DC)min) for single-ended sig-

nals as well as the limitations for overshoot and undershoot. Refer to "overshoot and Undersheet Specification"

Symbol

Parameter

DDR3-800/1066/1333/1600

unit

NOTE

1.35V

1.5V

min

max

min

max

V

IHdiff

differential input high

+0.18

NOTE 3

+0.20

NOTE 3

V

1

V

ILdiff

differential input low

NOTE 3

-0.18

NOTE 3

-0.20

V

1

V

IHdiff

(AC)

differential input high ac 2 x (V

IH

(AC) - V

REF

)

NOTE 3

2 x (V

IH

(AC) - V

REF

)

NOTE 3

V

2

V

ILdiff

(AC)

differential input low ac

NOTE 3

2 x (V

IL

(AC) - V

REF

)

NOTE 3

2 x (V

IL

(AC) - V

REF

)

V

2

0.0

tDVAC

V

IH

.DIFF.MIN

half cycle

Di

ffe

rent

ial

Inp

ut V

olt

ag

e (i.

e. DQS-DQS

, C

K

-C

K

)

time

tDVAC

V

IH

.DIFF.AC.MIN

V

IL

.DIFF.MAX

V

IL

.DIFF.AC.MAX

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