Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - DC/DC voltage regulator Switched-capacitor voltage converter SOIC 8

LMC7660

www.ti.com

SNOSBZ9C –APRIL 1997–REVISED APRIL 2013

LMC7660 Switched Capacitor Voltage Converter

Check for Samples: LMC7660

FEATURES

DESCRIPTION

The LMC7660 is a CMOS voltage converter capable

• Operation Over Full Temperature and Voltage

of converting a positive voltage in the range of +1.5V

Range without an External Diode

to +10V to the corresponding negative voltage of

• Low Supply Current, 200 μA Max

−1.5V to −10V. The LMC7660 is a pin-for-pin

• Pin-for-pin Replacement for the 7660

replacement for the industry-standard 7660. The

converter features: operation over full temperature

• Wide Operating Range 1.5V to 10V

and voltage range without need for an external diode,

• 97% Voltage Conversion Efficiency

low quiescent current, and high power efficiency.

• 95% Power Conversion Efficiency

The LMC7660 uses its built-in oscillator to switch 4

• Easy to Use, Only 2 External Components

power MOS switches and charge two inexpensive

• Extended Temperature Range

electrolytic capacitors.

Block Diagram

Pin Configuration

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 (19 pages)

PAGE 1
LMC7660 www.ti.com SNOSBZ9C – APRIL 1997 – REVISED APRIL 2013 LMC7660 Switched Capacitor Voltage Converter Check for Samples: LMC7660 FEATURES DESCRIPTION • The LMC7660 is a CMOS voltage converter capable of converting a positive voltage in the range of +1.5V to +10V to the corresponding negative voltage of −1.5V to −10V. The LMC7660 is a pin-for-pin replacement for the industry-standard 7660.
PAGE 2
LMC7660 SNOSBZ9C – APRIL 1997 – REVISED APRIL 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 10.5V −0.3V to (V+ + 0.3V) for V+ < 5.5V Input Voltage on Pin 6, 7 (3) + (V − 5.5V) to (V+ + 0.3V) for V+ > 5.5V Current into Pin 6 (3) 20 μA Output Short Circuit Duration (V+ ≤ 5.
PAGE 3
LMC7660 www.ti.com SNOSBZ9C – APRIL 1997 – REVISED APRIL 2013 ELECTRICAL CHARACTERISTICS(1) (continued) Symbol Parameter Conditions Typ LMC7660IN/ LMC7660IM Limit Rout Output Source IL = 20 mA 55 V = 2V, IL = 3 mA 110 Resistance Pin 6 Short to Gnd. Fosc Oscillator (2) Units Limits 100 Ω 120 max 200 Ω 300 max 10 kHz Frequency Peff Power Efficiency RL = 5 kΩ Vo Voltage Conversion RL = ∞ eff 97 99.9 Efficiency Iosc Oscillator Sink or Pin 7 = Gnd.
PAGE 4
LMC7660 SNOSBZ9C – APRIL 1997 – REVISED APRIL 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS 4 OSC Freq. vs OSC Capacitance Vout vs Iout @ V+ = 2V Figure 2. Figure 3. Vout vs Iout @ V+ = 5V Supply Current & Power Efficiency vs Load Current (V+ = 2V) Figure 4. Figure 5. Supply Current & Power Efficiency vs Load Current (V+ = 5V) Output Source Resistiance as a Function of Temperature Figure 6. Figure 7.
PAGE 5
LMC7660 www.ti.com SNOSBZ9C – APRIL 1997 – REVISED APRIL 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) Unloaded Oscillator Frequency as a Function of Temperature Output R vs Supply Voltage Figure 8. Figure 9. Peff vs OSC Freq. @ V+ = 5V Figure 10.
PAGE 6
LMC7660 SNOSBZ9C – APRIL 1997 – REVISED APRIL 2013 www.ti.com APPLICATION INFORMATION CIRCUIT DESCRIPTION The LMC7660 contains four large CMOS switches which are switched in a sequence to provide supply inversion Vout = −Vin. Energy transfer and storage are provided by two inexpensive electrolytic capacitors. Figure 11 shows how the LMC7660 can be used to generate −V+ from V+. When switches S1 and S3 are closed, Cp charges to the supply voltage V+. During this time interval, switches S2 and S4 are open.
PAGE 7
LMC7660 www.ti.com SNOSBZ9C – APRIL 1997 – REVISED APRIL 2013 Figure 11. Idealized Voltage Converter TYPICAL APPLICATIONS CHANGING OSCILLATOR FREQUENCY It is possible to dramatically reduce the quiescent operating current of the LMC7660 by lowering the oscillator frequency. The oscillator frequency can be lowered from a nominal 10 kHz to several hundred hertz, by adding a slow-down capacitor Cosc (Figure 12). As shown in the Typical Performance Curves the supply current can be lowered to the 10 μA range.
PAGE 8
LMC7660 SNOSBZ9C – APRIL 1997 – REVISED APRIL 2013 www.ti.com LOWERING OUTPUT IMPEDANCE Paralleling two or more LMC7660's lowers output impedance. Each device must have it's own pumping capacitor Cp, but the reservoir capacitor Cr is shared as depicted in Figure 14. The composite output resistance is: (3) INCREASING OUTPUT VOLTAGE Stacking the LMC7660s is an easy way to produce a greater negative voltage.
PAGE 9
LMC7660 www.ti.com SNOSBZ9C – APRIL 1997 – REVISED APRIL 2013 SPLIT V+ IN HALF Figure 17 is one of the more interesting applications for the LMC7660. The circuit can be used as a precision voltage divider (for very light loads), alternately it is used to generate a ½ supply point in battery applications. In the ½ cycle when S1 and S3 are closed, the supply voltage divides across the capacitors in a conventional way proportional to their value.
PAGE 10
LMC7660 SNOSBZ9C – APRIL 1997 – REVISED APRIL 2013 www.ti.com THERMOMETER SPANS 180°C Using the combined negative and positive multiplier of Figure 20 with an LM35 it is possible to make a μPower thermometer that spans a 180°C temperature range. The LM35 temperature sensor has an output sensitivity of 10 mV/°C, while drawing only 50 μA of quiescent current. In order for the LM35 to measure negative temperatures, a pull down to a negative voltage is required.
PAGE 11
LMC7660 www.ti.com SNOSBZ9C – APRIL 1997 – REVISED APRIL 2013 Vref = 1.235V *Low voltage operation Figure 22.
PAGE 12
LMC7660 SNOSBZ9C – APRIL 1997 – REVISED APRIL 2013 www.ti.com REVISION HISTORY Changes from Revision B (April 2013) to Revision C • 12 Page Changed layout of National Data Sheet to TI format ..........................................................................................................
PAGE 13
PACKAGE OPTION ADDENDUM www.ti.
PAGE 14
PACKAGE OPTION ADDENDUM www.ti.com 25-Feb-2014 (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.
PAGE 15
PACKAGE MATERIALS INFORMATION www.ti.com 8-Apr-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 LMC7660IMX SOIC D 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LMC7660IMX/NOPB SOIC D 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.
PAGE 16
PACKAGE MATERIALS INFORMATION www.ti.com 8-Apr-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LMC7660IMX SOIC D 8 2500 367.0 367.0 35.0 LMC7660IMX/NOPB SOIC D 8 2500 367.0 367.0 35.
PAGE 17
PAGE 18
PAGE 19
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.