LM2661MMX National Semiconductor, LM2661MMX Datasheet - Page 10

• Manufacturer Part Number: LM2661MMX
• Manufacturer: National Semiconductor

Specifications of LM2661MMX

• Operating Supply Voltage (min): 1.5V
• Operating Supply Voltage (max): 5.5V
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Package Type: MSOP
• Pin Count: 8
• Mounting: Surface Mount
• Lead Free Status / Rohs Status: Not Compliant

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Other Applications
REGULATING V
It is possible to regulate the output of the LM2660/LM2661
by use of a low dropout regulator (such as LP2951). The
whole converter is depicted in Figure 8. This converter can
give a regulated output from −1.5V to −5.5V by choosing the
proper resistor ratio:
where, V
Also, as shown in Figure 9 by operating LM2660/LM2661 in
voltage doubling mode and adding a linear regulator (such
as LP2981) at the output, we can get +5V output from an
input as low as +3V.
ref
= 1.235V
FIGURE 8. Combining LM2660/LM2661 with LP2951 to Make a Negative Adjustable Regulator
out
(Continued)
FIGURE 7. Generating +3V
10
The error flag on pin 5 of the LP2951 goes low when the
regulated output at pin 4 drops by about 5%. The LP2951
can be shutdown by taking pin 3 high.
in
from +V
in
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