LM2682MMX/NOPB

LM2682 www.ti.com SNVS044B – NOVEMBER 1999 – REVISED MAY 2013 LM2682 Switched Capacitor Voltage Doubling Inverter Check for Samples: LM2682 FEATURES DESCRIPTION • • • • The LM2682 is a CMOS charge-pump voltage inverter capable of converting positive voltage in the range of +2.0V to +5.5V to the corresponding doubled negative voltage of −4.0V to −11.0V respectively. The LM2682 uses three low cost capacitors to provide 10 mA of output current without the cost, size, and EMI related to inductor based circuits. With an operating current of only 150 μA and an operating efficiency greater than 90% with most loads, the LM2682 provides ideal performance for battery powered systems. The LM2682 offers a switching frequency of 6 kHz. 1 2 Inverts Then Doubles Input Supply Voltage Small VSSOP Package and SOIC Package 90Ω Typical Output Impedance 94% Typical Power Efficiency at 10 mA APPLICATIONS • • • • • LCD Contrast Biasing GaAs Power Amplifier Biasing Interface Power Supplies Handheld Instrumentation Laptop Computers and PDAs Typical Operating Circuit and Pin Configuration 8-Pin VSSOP or 8-Pin SOIC 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 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. All 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. Copyright © 1999–2013, Texas Instruments Incorporated LM2682 SNVS044B – NOVEMBER 1999 – REVISED MAY 2013 www.ti.com Absolute Maximum Ratings (1) Input Voltage (VIN) +5.8V VIN dV/dT 1V/μsec −11.6V VOUT VOUT Short-Circuit Duration Continuous −65°C to +150°C Storage Temperature Lead Temperature Soldering Power Dissipation (2) +300°C VSSOP 300 mW SOIC 470 mW TJMAX (1) +150°C Absolute Maximum Ratings are those values beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but do not ensure specific performance limits. For ensured specifications and test conditions, see the Electrical Characteristics. The maximum power dissipation must be de-rated at elevated temperatures (only needed for TA>85°C) and is limited by TJMAX (maximum junction temperature), θJ-A (junction to ambient thermal resistance) and TA (ambient temperature). θJ-A is 140°C/W for the SOIC-8 package and 220°C/W for the VSSOP-8 package. The maximum power dissipation at any temperature is:PDissMAX = (TJMAX − TA)/θJ-A up to the value listed in the Absolute Maximum Ratings. (2) Operating Ratings Human Body Model ESD Susceptibility (1) 2 kV Machine Model 200V Ambient Temp. Range −40°C to +85°C Junction Temp. Range −40°C to +125°C (1) The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. The machine model is a 200pF capacitor discharged directly into each pin. LM2682 Electrical Characteristics VIN = 5V and C1 = C2 = C3 = 3.3μF unless otherwise specified. Limits with bold typeface apply over the full operating ambient temperature range, −40°C to +85°C, limits with standard typeface apply for TA = 25°C. Symbol Parameter Conditions Typical (1) Max Units 5.5 V 150 300 400 μA IL = 10 mA 90 150 Ω IL=5 mA, VIN=2 V 110 250 Ω 12 30 kHz 6 15 kHz VIN Supply Voltage Range RL = 2 kΩ IIN Supply Current Open Circuit, No Load ROUT VOUT Source Resistance Min 2.0 200 fOSC Oscillator Frequency See (2) fSW Switching Frequency See (2) ηPOWER Power Efficiency RL = 2k (3) ηVOLTAGE Voltage Conversion Efficiency (1) (2) (3) 2 90 93 % 99.9 % Typical numbers are at 25°C and represent the most likely norm. The output switches operate at one half of the oscillator frequency, fOSC = 2fSW. The minimum specification is specified by design and is not tested. Submit Documentation Feedback Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: LM2682 LM2682 www.ti.com SNVS044B – NOVEMBER 1999 – REVISED MAY 2013 Table 1. PIN DESCRIPTIONS Pin Number Symbol 1 C1− Capacitor C1 negative terminal Description 2 C2+ Capacitor C2 positive terminal 3 C2− Capacitor C2 negative terminal 4 VOUT Negative output voltage (−2VIN) 5 GND Device ground 6 VIN Power supply voltage 7 C1+ Capacitor C1 positive terminal 8 NC No Connection Submit Documentation Feedback Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: LM2682 3 LM2682 SNVS044B – NOVEMBER 1999 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics VIN = 5V and TA = 25°C unless otherwise noted. Output Resistance vs Input Voltage Output Voltage vs Load Current Figure 1. Figure 2. Supply Current vs Input Voltage Output Resistance vs Temperature Figure 3. Figure 4. Output Voltage Ripple vs Load Current Figure 5. 4 Submit Documentation Feedback Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: LM2682 LM2682 www.ti.com SNVS044B – NOVEMBER 1999 – REVISED MAY 2013 BASIC APPLICATION CIRCUITS Figure 6. Doubling Voltage Inverter Figure 7. +5V to −5V Regulated Voltage Converter Submit Documentation Feedback Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: LM2682 5 LM2682 SNVS044B – NOVEMBER 1999 – REVISED MAY 2013 www.ti.com APPLICATION INFORMATION VOLTAGE DOUBLING INVERTER The main application of the LM2682 is to generate a negative voltage that is twice the positive input voltage. This circuit requires only three external capacitors and is connected as shown in Figure 6. It is important to keep in mind that the efficiency of the circuit is determined by the output resistance. A derivation of the output resistance is shown below: ROUT = 2(RSW1+RSW2+ESRC1+RSW3+RSW4+ESRC2) +2(RSW1+RSW2+ESRC1+RSW3+RSW4+ESRC2) + 1/(fOSC×C1) + 1/(fOSC×C2) + ESRC3 Using the assumption that all four switches have the same ON resistance our equation becomes: ROUT = 16RSW + 4ESRC1 + 4ESRC2 + ESRC3 + 1/(fOSC×C1) + 1/(fOSC×C2) Output resistance is typically 90Ω with an input voltage of +5V, an operating temperature of 25°C, and using low ESR 3.3 μF capacitors. This equation shows the importance of capacitor selection. Large value, low ESR capacitors will reduce the output resistance significantly but will also require a larger overall circuit. Smaller capacitors will take up less space but can lower efficiency greatly if the ESR is large. Also to be considered is that C1 must be rated at 6 VDC or greater while C2 and C3 must be rated at 12 VDC or greater. The amount of output voltage ripple is determined by the output capacitor C3 and the output current as shown in this equation: VRIPPLE P-P = IOUT × (2×ESRC3 + 1/[2×(fOSC×C3)]) Once again a larger capacitor with smaller ESR will give better results. +5V TO −5V REGULATED VOLTAGE CONVERTER Another application in which the LM2682 can be used is for generating a −5V regulated supply from a +5V unregulated supply. This involves using an op-amp and a reference and is connected as shown in Figure 7. The LM358 op-amp was chosen for its low cost and versatility and the LM4040-5.0 reference was chosen for its low bias current requirement. Of course other combinations may be used at the designer's discretion to fit accuracy, efficiency, and cost requirements. With this configuration the circuit is well regulated and is still capable of providing nearly 10 mA of output current. With a 9 mA load the circuit can typically maintain 5% regulation on the output voltage with the input varying anywhere from 4.5V to the maximum of 5.5V. With less load the results are even better. Voltage ripple concerns are reduced in this case since the ripple at the output of the LM2682 is reduced at the output by the PSRR of the op-amp used. 6 Submit Documentation Feedback Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: LM2682 LM2682 www.ti.com SNVS044B – NOVEMBER 1999 – REVISED MAY 2013 PARALLELING DEVICES Any number of devices can be paralleled to reduce the output resistance. As shown in Figure 8, each device must have its own pumping capacitors, C1 and C2, but only one shared output capacitor is required. The effective output resistance is the output resistance of one device divided by the number of devices used in parallel. Paralleling devices also gives the capability of increasing the maximum output current. The maximum output current now becomes the maximum output current for one device multiplied by the number of devices used in parallel. For example, if you parallel two devices you can get 20 mA of output current and have half the output resistance of one device supplying 10 mA. Figure 8. Paralleling Devices Submit Documentation Feedback Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: LM2682 7 LM2682 SNVS044B – NOVEMBER 1999 – REVISED MAY 2013 www.ti.com REVISION HISTORY Changes from Revision A (May 2013) to Revision B • 8 Page Changed layout of National Data Sheet to TI format ............................................................................................................ 7 Submit Documentation Feedback Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: LM2682 PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2020 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) (4/5) (6) LM2682MM/NOPB ACTIVE VSSOP DGK 8 1000 RoHS & Green SN Level-1-260C-UNLIM -40 to 85 S11A LM2682MMX/NOPB ACTIVE VSSOP DGK 8 3500 RoHS & Green SN Level-1-260C-UNLIM -40 to 85 S11A (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of