LP2996

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LP2996

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LP2996A

SNOSCY7 – JUNE 2014

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Typical Application (continued)

8.2.5 Level Shifting

If standards other than SSTL-2 are required, such as SSTL-3, it may be necessary to use a different scaling

pin. This has been illustrated in Figure 26 and Figure 27. Figure 26 shows how to use two resistors to level shift

can be used.

(11)

Figure 26. Increasing VTT by Level Shifting

internal reference voltage of VDDQ/2. The equations relating VTT and the resistors can be seen below:

(12)

Figure 27. Decreasing VTT by Level Shifting

8.2.5.1 Output Capacitor Selection

For applications utilizing the LP2996A to terminate SSTL-2 I/O signals the typical application circuit shown in

Figure 27 can be implemented.

This circuit permits termination in a minimum amount of board space and component count. Capacitor selection

can be varied depending on the number of lines terminated and the maximum load transient. However, with

bulk capacitors and addition to high frequency decoupling. Figure 28 shown below depicts an example circuit

aluminum electrolytic capacitors are used for their low ESR and low cost.

In most PC applications an extensive amount of decoupling is required because of the long interconnects

encountered with the DDR-SDRAM DIMMs mounted on modules. As a result bulk aluminum electrolytic

capacitors in the range of 1000uF are typically used.

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