LTC1261L - Switched Capacitor Regulated Voltage Inverter

1 LTC1261L11261lfaTYPICAL APPLICATION FEATURESDESCRIPTIONS witched Capacitor Regulated Voltage InverterThe LT C 1261L is a Switched - Capacitor Voltage Inverter designed to provide a Regulated negative Voltage from a single positive supply. The LTC1261L operates from a single to supply and provides an adjustable output Voltage from to 5V. The LTC1261L -4 needs a single to supply and provides a fixed output Voltage of 4V to respec-tively. Three external capacitors are required: a F flying Capacitor and an input and output bypass capacitors. An optional compensation Capacitor at ADJ (COMP) can be used to reduce the output Voltage version of the LTC1261L will supply up to 20mA output current with guaranteed output regulation of The LTC1261L includes an open-drain REG output that pulls low when the output is within 5% of the set value.

2 Quiescent current is typically 650 A when operating and 5 A in LTC1261L is available in 8-pin MSOP and SO Regulated Negative Voltage from a Single Positive Supplyn REG Pin Indicates Output is in Regulationn Adjustable or Fixed Output Voltagesn Output Regulation: Supply Current: 650 A Typn Shutdown Mode Drops Supply Current to 5 An Up to 20mA Output Current n Requires Only Three or Four External Capacitorsn Available in MS8 and SO-8 Packagesn GaAs FET Bias Generatorsn Negative Supply Generatorsn Battery-Powered Systemsn Single Supply ApplicationsL, LT, LT C, LT M, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. 4V Generator with Power Valid12348765 LTC1261L -4 SHDNREGOUTCOMPVCCC1+C1 F1261L FVOUT = 4 VAT 10mAPOWER VALID5VC11 F5V10kC3*100pF*OPTIONAL+Waveforms for 4V Generator with Power Valid0V TA02 POWER VALID5V5V0V0 VLTC1261L21261lfaPIN CONFIGURATIONABSOLUTE MAXIMUM RATINGSS upply Voltage (Note 2).

3 Voltage (Note 3) .. to Voltage , VCC to VOUT (Note 2) .. Pin .. to (VCC + )REG Pin .. to 6 VADJ Pin ..(VOUT ) to (VCC + )(Note 1)1234 VCCC1+C1 GND8765 SHDNREGOUTADJ (COMP)TOP VIEWMS8 PACKAGE8-LEAD PLASTIC MSOP TJMAX = 150 C, JA = 200 C/W12348765 TOP VIEWSHDNREGOUTADJ (COMP)VCCC1+C1 GNDS8 PACKAGE8-LEAD PLASTIC SO TJMAX = 150 C, JA = 135 C/WORDER INFORMATIONLEAD FREE FINISHTAPE AND REELPART MARKING*PACKAGE DESCRIPTIONTEMPERATURE RANGELTC1261 LCMS8#PBFLTC1261 LCMS8#TRPBFLTFM8-Lead Plastic MSOP0 C to 70 CLTC1261 LIMS8#PBFLTC1261 LIMS8#TRPBFLTFM8-Lead Plastic MSOP 40 C to 85 CLTC1261 LCMS8-4#PBFLTC1261 LCMS8-4#TRPBFLTFN8-Lead Plastic MSOP0 C to 70 CLTC1261 LIMS8-4#PBFLTC1261 LIMS8-4#TRPBFLTFN8-Lead Plastic MSOP 40 C to 85 # #TRPBFLTFP8-Lead Plastic MSOP0 C to 70 # #TRPBFLTFP8-Lead Plastic MSOP 40 C to 85 CLTC1261 LCS8#PBFLTC1261 LCS8#TRPBF1261L8-Lead Plastic SO0 C to 70 CLTC1261 LIS8#PBFLTC1261 LIS8#TRPBF1261L8-Lead Plastic SO 40 C to 85 CLTC1261 LCS8-4#PBFLTC1261 LCS8-4#TRPBF1261L48-Lead Plastic SO0 C to 70 CLTC1261 LIS8-4#PBFLTC1261 LIS8-4#TRPBF1261L48-Lead Plastic SO 40 C to 85 # #TRPBF261L458-Lead Plastic SO0 C to 70 #

4 #TRPBF261L458-Lead Plastic SO 40 C to 85 CConsult LT C Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping LT C Marketing for information on nonstandard lead based finish more information on lead free part marking, go to: For more information on tape and reel specifications, go to: Short-Circuit Duration .. IndefiniteCommercial Temperature Range (Note 4) ..0 C to 70 CIndustrial Temperature Range (Note 4) .. 40 C to 85 CStorage Temperature Range .. 65 C to 150 CLead Temperature (Soldering, 10 sec) ..300 CLTC1261L31261lfaELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25 C, C1 = F, COUT = F unless otherwise noted.

5 (Notes 2, 4)SYMBOLPARAMETERCONDITIONSMINTYPMAX UNITSVCCS upply Voltage LTC1261 LCMS8/LTC1261 LCS8 LTC1261 LCMS8-4/LTC1261 LCS8-4 (Note 5) (Note 5) l l l V V VVREFR eference CurrentVCC = , No Load, SHDN Floating VCC = , No Load, VSHDN = VCCl l650 51500 20 A AfOSCI nternal Oscillator FrequencyVCC = 5V, VOUT = 4V650kHzVOLREG Output Low VoltageIREG = 1mA, VCC = 5V, VOUT = Sink CurrentVREG = , VCC = VREG = , VCC = 5Vl l4 58 12mA mAIADJA djust Pin CurrentVADJ = 1 AVIHSHDN Input High VoltageVCC = 5Vl2 VVILSHDN Input Low VoltageVCC = Input CurrentVSHDN = AtONTurn-On TimeVCC = 5V, IOUT = 10mA, VOUT 4V ( LTC1261L ) VCC = 5V, IOUT = 5mA, VOUT = ( LTC1261L ) VCC = 5V, IOUT = 10mA, VOUT = 4V ( LTC1261L -4) VCC = 5V, IOUT = 5mA, VOUT = ( )l l l l250 250 250 2501500 1500 1500 1500 s s s sVOUTO utput Regulation ( LTC1261L ) VCC , 0mA IOUT 10mA VCC , 0mA IOUT 20mAl l VCC , 0mA IOUT 5mA VCC , 0mA IOUT 10mA VCC , 0mA IOUT 20mAl l l V VCC , 0mA IOUT 5mA VCC , 0mA IOUT 10mA VCC , 0mA IOUT 20mAl l l V VCC , 0mA IOUT 5mA VCC , 0mA IOUT 10mA VCC , 0mA IOUT 20mAl l l V VCC , 0mA IOUT 5mA VCC , 0mA IOUT 10mA VCC , 0mA IOUT 20mAl l l V VOutput Regulation ( LTC1261L / LTC1261L -4)

6 VCC , 0mA IOUT 5mA VCC , 0mA IOUT 10mA VCC , 0mA IOUT 20mAl l l V VOutput Regulation (LTC1261 ) VCC , 0mA IOUT 5mA VCC , 0mA IOUT 10mAl l VISCO utput Short-Circuit CurrentVOUT = 0V, VCC = 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and 2: All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to ground unless otherwise specified. Note 3: The output should never be set to exceed VCC 4: The LTC1261LC is guaranteed to meet specifications from 0 C to 70 C and is designed, characterized and expected to meet industrial temperature limits, but is not tested at 40 C and 85 C.

7 The LTC1261LI is guaranteed to meet specifications from 40 C and 85 5: The LTC1261L -4 and will operate with less than the minimum VCC specified in the electrical characteristics table, but they are not guaranteed to meet the VOUT PERFORMANCE CHARACTERISTICSO utput Voltage vs Supply VoltageMinimum Required VCC vs VOUT and IOUTM aximum Output Current vs Supply VoltageOutput Voltage vs Output CurrentOutput Voltage vs Output CurrentOutput Voltage vs Supply Voltage (See Test Circuits)OUTPUT CURRENT (mA)0 Voltage (V) G01 = 25 CVOUT = 2 VVCC = = 3 VOUTPUT CURRENT (mA)0 OUTPUT Voltage (V) G022530TA = 25 CVOUT = 4 VVCC = = 5 VSUPPLY Voltage (V) Voltage (V) G03 = 40 CVOUT = 2 VTA = 85 CTA = 25 CSUPPLY Voltage (V) Voltage (V)

8 G04 = 4 VTA = 40 CTA = 85 CTA = 25 COUTPUT Voltage (V) SUPPLY Voltage (V) 2 4 = 5mAIOUT = 10mAIOUT = 20mASUPPLY Voltage (V) OUTPUT CURRENT (mA) = 25 CVOUT = 2 VVOUT = 3 VVOUT = 4 VSupply Current vs Supply VoltageReference Voltage vs TemperatureSupply Current vs Supply VoltageSUPPLY Voltage (V)0 SUPPLY CURRENT (mA) = 40 CTA = 85 CTA = 25 CVOUT = 2 VIOUT = 0 SUPPLY Voltage (V) CURRENT (mA) = 85 CVOUT = = 0TA = 25 CTA = 40 CTEMPERATURE ( C) Voltage (V) 35 155251261L G09456585105125 VCC = 5 VADJ = 0 VLTC1261L51261lfaTYPICAL PERFORMANCE CHARACTERISTICSO scillator Frequency vs TemperatureStart-Up Time vs Supply VoltageOutput Short-Circuit Currentvs TemperatureTEMPERATURE ( C) 40 OSCILLATOR FREQUENCY (kHz)625650675801261L G10600575525 102050 259553565550725700TA = 25 CVOUT = 4 VVCC = 5 VSUPPLY Voltage (V) TIME (ms) = 2 VVOUT = 4 VTA = 25 CIOUT = 10mATEMPERATURE ( C) 40 SHORT-CIRCUIT CURRENT (mA)80100120801261L G1260400 102050 25955356520160140 VCC = = 5 VVCC = 3 VVCC = FUNCTIONSVCC (Pin 1): Power Supply.

9 This requires an input Voltage between and VCC must be bypassed to ground with at least a 1 F Capacitor placed in close proximity to the chip. See the Applications Information section for details. C1+ (Pin 2): C1 Positive Input. Connect a F Capacitor between C1+ and C1 . C1 (Pin 3): C1 Negative Input. Connect a F Capacitor from C1+ to C1 . GND (Pin 4): Ground. Connect to a low impedance ground. A ground plane will help to minimize regulation (COMP for Fixed Versions) (Pin 5): Output Adjust/Compensation Pin. For adjustable parts this pin is used to set the output Voltage . The output Voltage is divided down with an external resistor divider and fed back to this pin to set the Regulated output Voltage . Typically the resistor string should draw 10 A from the output to minimize errors due to the bias current at the adjust pin.

10 Fixed output Voltage parts have the internal resistor string connected to this pin inside the package. The pin can be used to trim the output Voltage if desired. It can also be used as an optional feedback compensation pin to reduce output ripple on both the adjustable and fixed output Voltage parts. See the Applications Information section for more information on compensation and output (Pin 6): Negative Voltage Output. This pin must be bypassed to ground with a 1 F or larger Capacitor . The value of the output Capacitor and its ESR have a strong effect on output ripple. See the Applications Information section for more (Pin 7): This is an open-drain output that pulls low when the output Voltage is within 5% of the set value. It will sink 5mA to ground with a 5V supply. The external circuitry must provide a pull-up or REG will not swing high.