TJ2997GD datasheet(10/13 Pages) HTC

10 / 13 page

DDR Termination Regulator

TJ2997

Apr, 2011 - R1.0.1

10/13

HTC

FIGURE 4. SSTL-2 Implementation with higher voltage rails

DDR-II APPLICATIONS

With the separate VDDQ pin and an internal resistor divider it is possible to use the TJ2997 in

applications utilizing DDR-II memory.

Figure 3 and Figure 4 show several implementations of

recommended circuits. Figure 3 shows the recommended circuit configuration for DDR-II applications.

The output stage is connected to the 1.8V rail and the AVIN pin can be connected to either a 3.3V or 5V

rail.

FIGURE 5. Recommended DDR-II Termination

If it is not desirable to use the 1.8V rail it is possible to connect the output stage to a 3.3V rail. Care

should be taken to do not exceed the maximum junction temperature as the thermal dissipation

increases with lower VTT output voltages. For this reason it is not recommended to power PVIN off a rail

higher than the nominal 3.3V. The advantage of this configuration is that it has the ability to source and

sink a higher maximum continuous current.

FIGURE 6. DDR-II Termination with higher voltage rails

TJ2997GD Arkusz danych(PDF) 10 Page - HTC Korea TAEJIN Technology Co.