Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - DC/DC voltage regulator Switched-capacitor voltage converter SOT 23 5

LM828

www.ti.com

SNOS035D –MARCH 2010–REVISED MAY 2013

LM828 Switched Capacitor Voltage Converter

Check for Samples: LM828

FEATURES

DESCRIPTION

The LM828 CMOS charge-pump voltage converter

• Inverts Input Supply Voltage

inverts a positive voltage in the range of +1.8V to

• SOT-23 Package

+5.5V to the corresponding negative voltage of −1.8V

• 20Ω Typical Output Impedance

to −5.5V. The LM828 uses two low cost capacitors to

provide up to 25 mA of output current.

• 97% Typical Conversion Efficiency at 5 mA

The LM828 operates at 12 kHz switching frequency

APPLICATIONS

to reduce output resistance and voltage ripple. With

an operating current of only 40 µA (operating

• Cellular Phones

efficiency greater than 96% with most loads), the

• Pagers

LM828 provides ideal performance for battery

• PDAs

powered systems. The device is in a tiny SOT-23

package.

• Operational Amplifier Power Supplies

• Interface Power Supplies

• Handheld Instruments

Basic Application Circuits

Voltage Inverter

+5V to −10V Converter

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 (15 pages)

PAGE 1
LM828 www.ti.com SNOS035D – MARCH 2010 – REVISED MAY 2013 LM828 Switched Capacitor Voltage Converter Check for Samples: LM828 FEATURES DESCRIPTION • • • • The LM828 CMOS charge-pump voltage converter inverts a positive voltage in the range of +1.8V to +5.5V to the corresponding negative voltage of −1.8V to −5.5V. The LM828 uses two low cost capacitors to provide up to 25 mA of output current.
PAGE 2
LM828 SNOS035D – MARCH 2010 – 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) Supply Voltage (V+ to GND, or GND to OUT) 5.8V V+ and OUT Continuous Output Current 50 mA Output Short-Circuit Duration to GND (3) Continuous Power Dissipation (TA = 25°C) 1 sec.
PAGE 3
LM828 www.ti.com SNOS035D – MARCH 2010 – REVISED MAY 2013 Test Circuit *C1 and C2 are 10 µF capacitors. Figure 1. LM828 Test Circuit Typical Performance Characteristics (Circuit of Figure 1, V+ = 5V unless otherwise specified) 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.
PAGE 4
LM828 SNOS035D – MARCH 2010 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) (Circuit of Figure 1, V+ = 5V unless otherwise specified) Output Voltage vs Load Current Efficiency vs Load Current Figure 6. Figure 7. Switching Frequency vs Supply Voltage Switching Frequency vs Temperature Figure 8. Figure 9. CONNECTION DIAGRAMS 5-Lead SOT-23 Package (DBV) Figure 10. SOT-23 Package – Top View See Package Number DBV0005A 4 Submit Documentation Feedback Figure 11.
PAGE 5
LM828 www.ti.com SNOS035D – MARCH 2010 – REVISED MAY 2013 Pin Functions PIN DESCRIPTIONS Pin Name 1 OUT Function Negative voltage output. 2 V+ 3 CAP− Power supply positive input. Connect this pin to the negative terminal of the charge-pump capacitor. 4 GND Power supply ground input. 5 CAP+ Connect this pin to the positive terminal of the charge-pump capacitor.
PAGE 6
LM828 SNOS035D – MARCH 2010 – REVISED MAY 2013 www.ti.com (2) Again, using a low ESR capacitor will result in lower ripple. CAPACITOR SELECTION The output resistance and ripple voltage are dependent on the capacitance and ESR values of the external capacitors. The output voltage drop is the load current times the output resistance, and the power efficiency is (3) IL2Rout Where IQ(V+) is the quiescent power loss of the IC device, and switch on-resistance, the two external capacitors and their ESRs.
PAGE 7
LM828 www.ti.com SNOS035D – MARCH 2010 – REVISED MAY 2013 CASCADING DEVICES Cascading the LM828s is an easy way to produce a greater negative voltage (e.g. A two-stage cascade circuit is shown in Figure 14). 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: Rout = nRout_1 + n/2 Rout_2 + ...
PAGE 8
LM828 SNOS035D – MARCH 2010 – REVISED MAY 2013 www.ti.com REGULATING VOUT It is possible to regulate the negative output of the LM828 by use of a low dropout regulator (such as the LP2980). The whole converter is depicted in Figure 16. This converter can give a regulated output from −1.8V to −5.5V by choosing the proper resistor ratio: Vout = Vref (1 + R1/R2) where, Vref = 1.
PAGE 9
LM828 www.ti.com SNOS035D – MARCH 2010 – REVISED MAY 2013 REVISION HISTORY Changes from Revision C (May 2013) to Revision D • Page Changed layout of National Data Sheet to TI format ............................................................................................................
PAGE 10
PACKAGE OPTION ADDENDUM www.ti.
PAGE 11
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.
PAGE 12
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) LM828M5 SOT-23 DBV 5 1000 178.0 8.4 LM828M5/NOPB SOT-23 DBV 5 1000 178.0 LM828M5X SOT-23 DBV 5 3000 178.0 LM828M5X/NOPB SOT-23 DBV 5 3000 178.0 3.2 3.2 1.4 4.0 8.0 Q2 8.4 3.2 3.2 1.4 4.0 8.0 Q2 8.4 3.2 3.2 1.4 4.0 8.0 Q2 8.4 3.2 3.
PAGE 13
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) LM828M5 SOT-23 DBV 5 1000 210.0 185.0 35.0 LM828M5/NOPB SOT-23 DBV 5 1000 210.0 185.0 35.0 LM828M5X SOT-23 DBV 5 3000 210.0 185.0 35.0 LM828M5X/NOPB SOT-23 DBV 5 3000 210.0 185.0 35.
PAGE 14
PAGE 15
IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.