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K4T1G044QF Datasheet, PDF (14/46 Pages) Samsung semiconductor – 1Gb F-die DDR2 SDRAM
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K4T1G044QF
K4T1G084QF
K4T1G164QF
datasheet
Rev. 1.11
DDR2 SDRAM
7.6 Differential input AC logic Level
Symbol
VID(AC)
VIX(AC)
Parameter
AC differential input voltage
AC differential cross point voltage
Min.
0.5
0.5 * VDDQ - 0.175
Max.
VDDQ
0.5 * VDDQ + 0.175
Units
V
V
NOTE
1
2
NOTE :
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 com-
plementary 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.
3. For information related to VPEAK value, Refer to overshoot/undershoot specification in device operation and timing datasheet; maximum peak ampli-
tude allowed for overshoot and undershoot.
VTR
VCP
VDDQ
VID
Crossing point
VIX or VOX
VSSQ
Figure 2. Differential signal levels
7.7 Differential AC output parameters
Symbol
Parameter
Min.
Max.
VOX(AC) AC differential cross point voltage
0.5 * VDDQ - 0.125
0.5 * VDDQ + 0.125
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 .
voltage at which differential output signals must cross.
Units
V
NOTE
1
VOX(AC) indicates the
8. ODT DC electrical characteristics
PARAMETER/CONDITION
Rtt effective impedance value for EMRS(A6,A2)=0,1; 75 ohm
Rtt effective impedance value for EMRS(A6,A2)=1,0; 150 ohm
Rtt effective impedance value for EMRS(A6,A2)=1,1; 50 ohm
Deviation of VM with respect to VDDQ/2
SYMBOL
Rtt1(eff)
Rtt2(eff)
Rtt3(eff)
delta VM
MIN NOM MAX UNITS NOTE
60
75
90
ohm
1
120
150
180
ohm
1
40
50
60
ohm
1
-6
+6
%
1
NOTE : Test condition for Rtt measurements
Measurement Definition for Rtt(eff): Apply VIH (AC) and VIL (AC) to test pin separately, then measure current I(VIH (AC)) and I( VIL (AC)) respectively. VIH (AC), VIL
(AC)(DC), and VDDQ values defined in SSTL_18
VIH (AC) - VIL (AC)
Rtt(eff) =
I(VIH (AC)) - I(VIL (AC))
delta VM =
2 x VM
- 1 x 100%
VDDQ
Measurement Definition for VM: Measure voltage (VM) at test pin (midpoint) with no load.
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