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LM2681

www.ti.com

SNVS042B –MARCH 1999–REVISED MAY 2013

LM2681 Switched Capacitor Voltage Converter

Check for Samples: LM2681

FEATURES

DESCRIPTION

The LM2681 CMOS charge-pump voltage converter

• Doubles or Splits Input Supply Voltage

operates as a voltage doubler for an input voltage in

• SOT-23 6-Lead Package

the range of +2.5V to +5.5V. Two low cost capacitors

• 15Ω Typical Output Impedance

and a diode (needed during start-up) is used in this

circuit to provide up to 20 mA of output current. The

• 90% Typical Conversion Efficiency at 20 mA

LM2681 can also work as a voltage divider to split a

voltage in the range of +1.8V to +11V in half.

APPLICATIONS

The LM2681 operates at 160 kHz oscillator frequency

• Cellular Phones

to reduce output resistance and voltage ripple. With

• Pagers

an operating current of only 550 µA (operating

• PDAs

efficiency greater than 90% with most loads) the

LM2681 provides ideal performance for battery

• Operational Amplifier Power Suppliers

powered systems. The device is in a SOT-23, 6-lead

• Interface Power Suppliers

package.

• Handheld Instruments

Basic Application Circuits

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 (16 pages)

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LM2681 www.ti.com SNVS042B – MARCH 1999 – REVISED MAY 2013 LM2681 Switched Capacitor Voltage Converter Check for Samples: LM2681 FEATURES DESCRIPTION • • • • The LM2681 CMOS charge-pump voltage converter operates as a voltage doubler for an input voltage in the range of +2.5V to +5.5V. Two low cost capacitors and a diode (needed during start-up) is used in this circuit to provide up to 20 mA of output current. The LM2681 can also work as a voltage divider to split a voltage in the range of +1.
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LM2681 SNVS042B – MARCH 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. Absolute Maximum Ratings (1) (2) V+ to GND Voltage 5.8V OUT to GND Voltage 11.6V OUT to V+ Voltage 5.8V V+ and OUT Continuous Output Current 30 mA Output Short-Circuit Duration to GND (3) 1 sec.
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LM2681 www.ti.com SNVS042B – MARCH 1999 – REVISED MAY 2013 Test Circuit Figure 1.
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LM2681 SNVS042B – MARCH 1999 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (Circuit of Figure 1, V+ = 5V unless otherwise specified) 4 Supply Current vs Supply Voltage Supply Current vs Temperature Figure 2. Figure 3. Output Source Resistance vs Supply Voltage Output Source Resistance vs Temperature Figure 4. Figure 5. Output Voltage Drop vs Load Current Efficiency vs Load Current Figure 6. Figure 7.
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LM2681 www.ti.com SNVS042B – MARCH 1999 – REVISED MAY 2013 Typical Performance Characteristics (continued) (Circuit of Figure 1, V+ = 5V unless otherwise specified) Oscillator Frequency vs Supply Voltage Oscillator Frequency vs Temperature Figure 8. Figure 9.
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LM2681 SNVS042B – MARCH 1999 – REVISED MAY 2013 www.ti.com CONNECTION DIAGRAM Figure 10. SOT-23, 6-Lead Package – Top View See Package Number DBV Figure 11.
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LM2681 www.ti.com SNVS042B – MARCH 1999 – REVISED MAY 2013 APPLICATION INFORMATION POSITIVE VOLTAGE DOUBLER The main application of the LM2681 is to double the input voltage. The range of the input supply voltage is 2.5V to 5.5V. The output characteristics of this circuit can be approximated by an ideal voltage source in series with a resistance. The voltage source equals 2V+.
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LM2681 SNVS042B – MARCH 1999 – REVISED MAY 2013 www.ti.com Low ESR Capacitor Manufacturers Manufacturer Phone Capacitor Type Nichicon Corp. (708)-843-7500 PL & PF series, through-hole aluminum electrolytic AVX Corp.
PAGE 9
LM2681 www.ti.com SNVS042B – MARCH 1999 – REVISED MAY 2013 REGULATING VOUT It is possible to regulate the output of the LM2681 by use of a low dropout regulator (such as LP2980-5.0). The whole converter is depicted in Figure 15. A different output voltage is possible by use of LP2980-3.3, LP2980-3.0, or LP2980-adj.
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LM2681 SNVS042B – MARCH 1999 – REVISED MAY 2013 www.ti.com REVISION HISTORY Changes from Revision A (May 2013) to Revision B • 10 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 continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-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) LM2681M6/NOPB SOT-23 DBV 6 1000 178.0 8.4 LM2681M6X SOT-23 DBV 6 3000 178.0 LM2681M6X/NOPB SOT-23 DBV 6 3000 178.0 3.2 3.2 1.4 4.0 8.0 Q3 8.4 3.2 3.2 1.4 4.0 8.0 Q3 8.4 3.2 3.2 1.4 4.0 8.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM2681M6/NOPB SOT-23 DBV 6 1000 210.0 185.0 35.0 LM2681M6X SOT-23 DBV 6 3000 210.0 185.0 35.0 LM2681M6X/NOPB SOT-23 DBV 6 3000 210.0 185.0 35.
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