LM2661 Datasheet | National Semiconductor

Description The LM2660/LM2661 CMOS charge-pump voltage converter inverts a positive voltage in the range of 1.5V to 5.5V to the corresponding negative voltage. The LM2660/LM2661 uses two low cost capacitors to provide 100 m A of output current without the cost, size, and EMI related to inductor based converters. With an operating current of only 120 µA and operating efficiency greater than 90% at most loads, the LM2660/LM2661 provides ideal performance for battery powered systems. The LM2660/LM2661 may also be used as a positive voltage doubler. The oscillator frequency can be lowered by adding an external capacitor to the OSC pin. Also, the OSC pin may be used to drive the LM2660/LM2661 with an external clock. For LM2660, a frequency control (FC) pin selects the oscillator frequency of 10 k Hz or 80 k Hz. For LM2661, an external shutdown (SD) pin replaces the FC pin. The SD pin can be used to disable the device and reduce the quiescent current to 0.5 µA. The oscillator frequency for the LM2661 is 80 k Hz. Features n n n n n n Inverts or doubles input supply voltage Narrow SO-8 and Mini SO-8 Package 6.5Ω typical output resistance 88% typical conversion efficiency at 100 m A (LM2660) selectable oscillator frequency: 10 k Hz/80 k Hz (LM2661) low current shutdown mode Applications n n n n n n Laptop puters Cellular phones Medical instruments Operational amplifier power supplies Interface power supplies Handheld instruments Basic Application Circuits Voltage Inverter Positive Voltage Doubler DS012911-3 DS012911-4 Splitting VIN in Half DS012911-26 © 1999 National Semiconductor Corporation DS012911 .national. LM2660/LM2661 Absolute Maximum Ratings (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage (V+ to GND, or GND to OUT) 6V LV (OUT - 0.3V) to (GND + 3V) FC, OSC The least negative of (OUT - 0.3V) or (V+ - 6V) to (V+ + 0.3V) V+ and...