Datasheet

LP2992
www.ti.com SNVS171G –NOVEMBER 2001–REVISED MARCH 2013
REVERSE INPUT-OUTPUT VOLTAGE
The PNP power transistor used as the pass element in the LP2992 has an inherent diode connected between
the regulator output and input. During normal operation (where the input voltage is higher than the output) this
diode is reverse-biased.
However, if the output is pulled above the input, this diode will turn ON and current will flow into the regulator
output. In such cases, a parasitic SCR can latch which will allow a high current to flow into V
IN
(and out the
ground pin), which can damage the part.
In any application where the output may be pulled above the input, an external Schottky diode must be
connected from V
IN
to V
OUT
(cathode on V
IN
, anode on V
OUT
), to limit the reverse voltage across the LP2992 to
0.3V (see Absolute Maximum Ratings).
WSON MOUNTING
The WSON package requires specific mounting techniques which are detailed in Application Note # 1187
(literature number SNOA401). Referring to the section PCB Design Recommendations, it should be noted that
the pad style which should be used with the WSON package is the NSMD (non-solder mask defined) type.
The thermal dissipation of the WSON package is directly related to the printed circuit board construction and the
amount of additional copper area.
For the LP2992 in the NGD0006A 6-Lead WSON package, the junction-to-case thermal rating, θ
JC
, is 19°C/W,
where the case is actually the bottom of the package at the center of the DAP. The junction-to-ambient thermal
performance for the LP2992 in the NGD0006A 6-Lead WSON package, using the JEDEC standards is
summarized in the following table:
Board Thermal
θ
JC
θ
JA
Type Vias
JEDEC
None 19°C/W 282°C/W
2–Layer
1 19°C/W 94°C/W
2 19°C/W 78°C/W
JEDEC
4–Layer
4 19°C/W 66°C/W
6 19°C/W 62°C/W
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