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User's Guide
SNVA014C–November 1999–Revised April 2013
AN-1142 LM2661/3/4 Evaluation Board
1 Introduction
The LM2661, LM2663, and LM2664 are part of a family of CMOS charge-pump voltage converters
(Table 3). Each uses two small capacitors to achieve voltage inversion or voltage doubling without the
cost, size, and EMI of inductor based converters. Each device has a shutdown feature and the LM2661
and LM2663 also provide the ability to run the clock oscillator from an external source. You may also slow
the clock with an external capacitor on the LM2661 and LM2663. The small size and low profile of these
circuits makes them attractive for cellular phones, laptop computers, Op Amp power supplies, interface
power supplies, medical instruments, PDAs, and handheld instruments.
The LM2661 comes in SOIC-8 and VSSOP-8 packages and requires only an extra diode to double the
input voltage and provide up to 100mA of output current. It has a typical efficiency of 88% at 100mA
output and a typical output resistance of 6.5 Ω. This circuit typically draws only 500 nA of supply current in
shutdown mode and 120 µA when operating. The internal oscillator frequency is 80 kHz and the input
voltage range is +2.5 V to +5.5 V . The LM2661 is also capable of inverting an input voltage from +1.5 V
to +5.5 V when used in a different configuration.
The LM2663 comes in a SOIC-8 package and inverts the input voltage to provide up to 200mA of output
current. It has a typical efficiency of 86% at 200 mA output and a typical output resistance of 3.5 Ω. This
circuit draws only 10 µA of supply current in shutdown and 300 µA when operating. The internal oscillator
frequency is 150 kHz and the input voltage range is +1.5 V to +5.5 V . The LM2663 is also capable of
doubling an input voltage from +2.5 V to +5.5 V when used in a different configuration.
The LM2664 comes in a SOT23-6 package and inverts the input voltage to provide up to 40 mA of output
current. It has a typical efficiency of 91% at 40 mA output and a typical output resistance of 12 Ω. This
circuit draws only 1 µA of supply current in shutdown and 220 µA when on. The oscillator frequency is 160
kHz and the input voltage range is +1.8 V to +5.5 V
(1)
Figure 1 contains the schematic for each circuit used.
A silkscreen for the evaluation board is shown in Figure 2.
A listing of the products used is shown in Table 1.
A listing of the switched capacitor family is given in Table 3.
(1)
Maximum input voltage for any input on this evaluation board is +5.5 V.
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SNVA014C–November 1999–Revised April 2013 AN-1142 LM2661/3/4 Evaluation Board
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