LM2662, LM2663
SNVS002D –JANUARY 1999–REVISED MAY 2013
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REGULATING Vout
It is possible to regulate the output of the LM2662/LM2663 by use of a low dropout regulator (such as LP2986).
The whole converter is depicted in Figure 24. This converter can give a regulated output from −1.5V to −5.5V by
choosing the proper resistor ratio:
(6)
where, Vref = 1.23V
The error flag on pin 7 of the LP2986 goes low when the regulated output at pin 5 drops by about 5% below
nominal. The LP2986 can be shutdown by taking pin 8 low. The less than 1 μA quiescent current in the
shutdown mode is favorable for battery powered applications.
Figure 24. Combining LM2662/LM2663 with LP2986 to Make a Negative Adjustable Regulator
Also, as shown in Figure 25 by operating the LM2662/LM2663 in voltage doubling mode and adding a low
dropout regulator (such as LP2986) at the output, we can get +5V output from an input as low as +3.3V.
Figure 25. Generating +5V from +3.3V Input Voltage
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