DDR2 AC and DC operating conditions

1. Recommended DC operating condition(SSTL_18)
1.1 VDD-supply voltage
1.2 VDDQ- IO supply voltage
1.3 VDDL - DLL supply voltage
1.4 Vref(DC)- I/O reference voltage: equal to VDDQ/2 of the transmitting device
1.5 Vtt -- I/O termination voltage
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* VDD/VDDQ/VDDL: 1.7V(min)---1.8V(nom)---1.9V(max)
* Vref(DC): 0.49VDDQ ---0.5VDDQ ---0.51VDDQ
0.833V ---0.9V ---0.969V
* Vtt: Vref(DC)-40 Vref(DC) Vref(DC)+40 mV
0.793V --- 0.9V --- 1.009V
2. DC Logic Level: Vref(DC)+/-125mV
high: VIH(DC): Vref(DC)+125mV ---- VDDQ (or VDDQ+300mV,not to exceed 1.9V)
low : VIL(DC) -300mV --- Vref(DC)-125mV
3. AC logic Level:
high: Vref(DC)+200mV/250mV --VDDQ
low: -300mV --- Vref(DC)-200mV/250mV note: 250mV for DDR2-400/533(-5E/-37E devices)