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LM2660

www.ti.com

SNVS135D –SEPTEMBER 1999–REVISED MAY 2013

LM2660 Switched Capacitor Voltage Converter

Check for Samples: LM2660

FEATURES

DESCRIPTION

The LM2660 CMOS charge-pump voltage converter

• Inverts or Doubles Input Supply Voltage

is a versatile unregulated switched capacitor inverter

• Narrow SO-8 and Mini SO-8 Package

or doubler. Operating from a wide 1.5V to 5.5V

• 6.5Ω Typical Output Resistance

supply voltage, the LM2660 uses two low-cost

capacitors to provide 100 mA of output current

• 88% Typical Conversion Efficiency at 100 mA

without the cost, size and EMI related to inductor-

• Selectable Oscillator Frequency: 10 kHz/80

based converters. With an operating current of only

kHz

120 µA and operating efficiency greater than 90% at

• Optional External Oscillator Input

most loads, the LM2660 provides ideal performance

for battery-powered systems. LM2660 devices can be

operated directly in parallel to lower output

APPLICATIONS

impedance, thus providing more current at a given

• Laptop Computers

voltage.

• Cellular Phones

The FC (frequency control) pin selects between a

• Medical Instruments

nominal 10 kHz or 80 kHz oscillator frequency. The

• Operational Amplifier Power Supplies

oscillator frequency can be lowered by adding an

external capacitor to the OSC pin. Also, the OSC pin

• Interface Power Supplies

may be used to drive the LM2660 with an external

• Handheld Instruments

clock up to 150 kHz. Through these methods, output

ripple frequency and harmonics may be controlled.

Additionally, the LM2660 may be configured to divide

a positive input voltage precisely in half. In this mode,

input voltages as high as 11V may be used.

Basic Application Circuits

Voltage Inverter Positive Voltage Doubler

Splitting V

in Half

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (20 pages)

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LM2660 www.ti.com SNVS135D – SEPTEMBER 1999 – REVISED MAY 2013 LM2660 Switched Capacitor Voltage Converter Check for Samples: LM2660 FEATURES DESCRIPTION • • • • • The LM2660 CMOS charge-pump voltage converter is a versatile unregulated switched capacitor inverter or doubler. Operating from a wide 1.5V to 5.5V supply voltage, the LM2660 uses two low-cost capacitors to provide 100 mA of output current without the cost, size and EMI related to inductorbased converters.
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LM2660 SNVS135D – SEPTEMBER 1999 – REVISED MAY 2013 www.ti.com These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. (1) (2) Absolute Maximum Ratings Supply Voltage (V+ to GND, or GND to OUT) 6V (OUT − 0.3V) to (GND + 3V) LV The least negative of (OUT − 0.3V) or (V+ − 6V) to (V+ + 0.
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LM2660 www.ti.com SNVS135D – SEPTEMBER 1999 – REVISED MAY 2013 Electrical Characteristics Limits in standard typeface are for TJ = 25°C, and limits in boldface type apply over the full operating temperature range. Unless otherwise specified: V+ = 5V, FC = Open, C1 = C2 = 150 μF. (1) Symbol V+ Parameter Supply Voltage RL = 1k IQ Supply Current IL Output Current ROUT Output Resistance fOSC Oscillator Frequency fSW Switching Frequency IOSC OSC Input Current PEFF (2) 3.5 5.
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LM2660 SNVS135D – SEPTEMBER 1999 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (Circuit of Figure 1) 4 Supply Current vs Supply Voltage Supply Current vs Oscillator Frequency Figure 2. Figure 3. Output Source Resistance vs Supply Voltage Output Source Resistance vs Temperature Figure 4. Figure 5. Efficiency vs Load Current Output Voltage Drop vs Load Current Figure 6. Figure 7.
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LM2660 www.ti.com SNVS135D – SEPTEMBER 1999 – REVISED MAY 2013 Typical Performance Characteristics (continued) (Circuit of Figure 1) Efficiency vs Oscillator Frequency Output Voltage vs Oscillator Frequency Figure 8. Figure 9. Oscillator Frequency vs External Capacitance Oscillator Frequency vs Supply Voltage (FC = V+) Figure 10. Figure 11. Oscillator Frequency vs Supply Voltage (FC = Open) Oscillator Frequency vs Temperature (FC = V+) Figure 12. Figure 13.
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LM2660 SNVS135D – SEPTEMBER 1999 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) (Circuit of Figure 1) Oscillator Frequency vs Temperature (FC = Open) Figure 14. CONNECTION DIAGRAMS Figure 15. Top View 8-Lead SOIC (D) or VSSOP (DGK) Pin Description Pin Function Name Voltage Inverter Voltage Doubler Frequency control for internal oscillator: FC = open, fOSC = 10 kHz (typ); 1 FC FC = V+, fOSC = 80 kHz (typ); Same as inverter.
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LM2660 www.ti.com SNVS135D – SEPTEMBER 1999 – REVISED MAY 2013 Circuit Description The LM2660 contains four large CMOS switches which are switched in a sequence to invert the input supply voltage. Energy transfer and storage are provided by external capacitors. Figure 16 illustrates the voltage conversion scheme. When S1 and S3 are closed, C1 charges to the supply voltage V+. During this time interval switches S2 and S4 are open.
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LM2660 SNVS135D – SEPTEMBER 1999 – REVISED MAY 2013 www.ti.com APPLICATION INFORMATION SIMPLE NEGATIVE VOLTAGE CONVERTER The main application of LM2660 is to generate a negative supply voltage. The voltage inverter circuit uses only two external capacitors as shown in the Basic Application Circuits. The range of the input supply voltage is 1.5V to 5.5V. For a supply voltage less than 3.5V, the LV pin must be connected to ground to bypass the internal regulator circuitry.
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LM2660 www.ti.com SNVS135D – SEPTEMBER 1999 – REVISED MAY 2013 The switching frequency of the converter (also called the charge pump frequency) is half of the oscillator frequency. NOTE OSC cannot be driven by an external clock in the voltage-doubling mode. Table 1.
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LM2660 SNVS135D – SEPTEMBER 1999 – REVISED MAY 2013 www.ti.com Figure 17. Output Source Resistance vs Oscillator Frequency Table 2. Low ESR Capacitor Manufacturers Manufacturer Capacitor Type Nichicon Corp. PL, PF series, through-hole aluminum electrolytic AVX Corp.
PAGE 11
LM2660 www.ti.com SNVS135D – SEPTEMBER 1999 – REVISED MAY 2013 CASCADING DEVICES Cascading the LM2660s is an easy way to produce a greater negative voltage (as shown in Figure 19). If n is the integer representing the number of devices cascaded, the unloaded output voltage Vout is (−nVin). The effective output resistance is equal to the weighted sum of each individual device: (5) A three-stage cascade circuit shown in Figure 20 generates −3Vin, from Vin.
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LM2660 SNVS135D – SEPTEMBER 1999 – REVISED MAY 2013 www.ti.com REGULATING Vout It is possible to regulate the output of the LM2660 by use of a low dropout regulator (such as LP2951). The whole converter is depicted in Figure 22. This converter can give a regulated output from −1.5V to −5.5V by choosing the proper resistor ratio: (6) where, Vref = 1.235V 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.
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LM2660 www.ti.com SNVS135D – SEPTEMBER 1999 – REVISED MAY 2013 REVISION HISTORY Changes from Revision C (May 2013) to Revision D • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 1-Nov-2013 (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-May-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant LM2660MM VSSOP DGK 8 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 LM2660MM/NOPB VSSOP DGK 8 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 LM2660MX SOIC D 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-May-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM2660MM VSSOP DGK 8 1000 210.0 185.0 35.0 LM2660MM/NOPB VSSOP DGK 8 1000 210.0 185.0 35.0 LM2660MX SOIC D 8 2500 367.0 367.0 35.0 LM2660MX/NOPB SOIC D 8 2500 367.0 367.0 35.
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