LP2996A VTT Maximum Rating

Kobayashi,

VTT is the regulated output for LP2996A. This means that no voltage or current should be applied to this pin because it is not an input pin. The datasheet states that VTT is regulated output that regulates to VDDQ/2. Since the VDDQ absolute maximum value is 6V, this means VTT absolute maximum is 3V. In the Electrical Characteristics section 6.5 of the datasheet, you can see the MIN, TYP, and MAX values for VTT under normal operating conditions for DDR I, DDR II, and DDR III applications. From this section, it appears that during normal operating conditions, VTT maximum is 1.39V and occurs in DDR I applications with Vin = VDDQ = 2.7V.

Important note: VTT pin is capable of sinking and sourcing current and the LP2996A is designed to handle peak transient currents of up to ± 3 A with a fast transient response. If a transient is expected to last above the maximum continuous current rating for a significant amount of time, then the output capacitor should be sized large enough to prevent an excessive voltage drop. Despite the fact that the LP2996A is designed to handle large transient output currents it is not capable of handling these for long durations, under all conditions. The reason for this is the standard packages are not able to thermally dissipate the heat as a result of the internal power loss. If large currents are required for longer durations, then care should be taken to ensure that the maximum junction temperature is not exceeded.

I hope this helps you! Please let me know if you have any other questions. Thank you!

-Michael