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K4T1G044QA Datasheet, PDF (13/28 Pages) Samsung semiconductor – 1Gb A-die DDR2 SDRAM Specification
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1G A-die DDR2 SDRAM
DDR2 SDRAM
Differential input AC logic Level
Symbol
Parameter
Min.
Max.
Units
Notes
VID(AC)
AC differential input voltage
0.5
VDDQ + 0.6
V
1
VIX(AC)
AC differential cross point voltage
0.5 * VDDQ - 0.175
0.5 * VDDQ + 0.175
V
2
Notes :
1. VID(AC) specifies the input differential voltage |VTR -VCP | required for switching, where VTR is the true input signal (such as CK, DQS, LDQS or
UDQS) and VCP is the complementary input signal (such as CK, DQS, LDQS or UDQS). The minimum value is equal to VIH (AC) - VIL(AC).
2. The typical value of VIX(AC) is expected to be about 0.5 * VDDQ of the transmitting device and VIX(AC) is expected to track variations in VDDQ. VIX(AC)
indicates the voltage at which differential input signals must cross.
VTR
VCP
VDDQ
VID
Crossing point
VIX or VOX
VSSQ
< Differential signal levels >
Differential AC output parameters
Symbol
VOX(AC)
Parameter
AC differential cross point voltage
Min.
0.5 * VDDQ - 0.125
Max.
0.5 * VDDQ + 0.125
Units
V
Note
1
Note :
1. The typical value of VOX(AC) is expected to be about 0.5 * VDDQ of the transmitting device and VOX(AC) is expected to track variations in VDDQ.
VOX(AC) indicates the voltage at which differential output signals must cross.
Page 13 of 28
Rev. 1.1 Aug. 2005
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