The LP2998 datasheet says, "The device also supports DDR3 and DDR3L VTT bus termination with VDDQ min of 1.35 V". This could be interpreted to mean that at 1.34999V the device may not work (I know that's not the intent of the statement, but am trying to illustrate the nature of the concern.). It almost sounds like 1.35V VDDQ is right near the bottom end of the device capability (never a good place to operate a device).
Q1. When using the LP2998 for DDR3L with VDDQ nominal of 1.35V, what are the upper and lower VDDQ voltage tolerances the LP2998 supports? For example, is a VDDQ voltage tolerance of 1.283V to 1.45V acceptable (this is what the DDR3L memory chip lists as the VDDQ range)?
Q2. Also, can you provide something like Figure 20 in the datasheet, but tailored for 1.35V VDDQ? Where would one find that specification in the datasheet?
Q3. And finally, in skimming the LP2998 datasheet, one almost gets the impression that this part was not originally designed for DDR3L (or maybe not even for DDR3), but in some cases it can be made to work with them. That makes one a bit nervous about using the LP2998 in such a design. Generally one is better off going with a part that was designed for, and has lots of success stories / mileage in the specific application one intends to use it. So the question becomes, for a new DDR3L (1.35V) or DDR3 (1.5V) design that needs extended operating temperature range (say -40C to +95C), which is a better choice, LP2998, TPS53317A, or maybe something else entirely, or maybe even the fairly simple and widely used TPS51200 (where we'd be pushing our luck at the upper end of the operating temperature range)?
Please advise
Thanks
