FEATURES DESCRIPTIO APPLICATIO S. LTC1682/LTC /LTC Doubler Charge Pumps with Low Noise Linear Regulator TYPICAL APPLICATIO

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LTC/LTC-./LTC- Doubler Charge Pumps with Low Noise Linear Regulator FEATRES Low Output Noise: µv RMS (khz BW) Adjustable or Fixed Boosted Output Adjustable Output Voltage Range:.V to.

1 LTC/LTC-./LTC- Doubler Charge Pumps with Low Noise Linear Regulator FEATRES Low Output Noise: µv RMS (khz BW) Adjustable or Fixed Boosted Output Adjustable Output Voltage Range:.V to.v Fixed Output Voltages:.V, V Wide Input Voltage Range:.V to.v ses Small Ceramic Capacitors No Inductors Required Output Current up to ma khz Switching Frequency Low Operating Current: µa Low Shutdown Current: µa Internal Thermal Shutdown and Current Limiting Available in -Pin MSOP and SO Packages APPLICATIO S VCO Power Supplies in Cellular Phones -Way Pagers Wireless PCMCIA Cards Portable Medical Instruments Low Power Data Acquisition Remote Transmitters DESCRIPTIO The LTC /LTC-./LTC- are doubler charge pumps with an internal low noise, low dropout (LDO) linear regulator. These parts are designed to provide a low noise boosted supply voltage for powering noise sensitive devices such as high frequency VCOs in wireless applications. An internal doubler charge pump converts a.v to.v input to a boosted output, while the internal LDO regulator converts the boosted voltage to a low noise regulated output. The adjustable version allows the user to set via external resistors connected to FB. The regulator is capable of supplying up to ma of output current. Shutdown reduces the supply current to < µa, removes the load from by disabling the regulator and discharges to ground through a Ω switch. The LTC LDO regulator is stable with only µf on the output. Small ceramic capacitors can be used, reducing PC board area. The LTC/LTC-./LTC- are short-circuit and over temperature protected. The parts are available in -pin MSOP and SO packages., LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO.V VCO Power Supply, =.V to.v Open-Loop Close-In Phase Noise.V TO.V.µF SHTDOWN CPO.V C SHDN LTC k FB µf k k pf B P VCO MRATA MQE-9 M C pf pf k f OT 9MHz V C AMPLITDE db/div TA CENTER = 9MHz SPAN = khz RES BW = khz VBW = Hz SWP = sec REF = dbm TA

2 LTC/LTC-./LTC- ABSOLTE MAXIMM RATINGS W W W (Note ) to Ground....V to V Voltage....V to V CPO to Ground... V SHDN, FILT/FB Voltage to Ground....V to (.V) Short-Circuit Duration... Indefinite I OT... 9mA Operating Temperature Range Commercial... C to C Extended Commercial (Note )... C to C Industrial... C to C Storage Temperature Range... C to C Lead Temperature (Soldering, sec)... C Maximum Junction Temperature... C W PACKAGE/ORDER INFORMATION SHDN FILT/FB* TOP VIEW CPO C MS PACKAGE -LEAD PLASTIC MSOP *PIN = FILT FOR LTC-./LTC- = FB FOR LTC T JMAX = C, θ JA = C/ W Consult factory for Military grade parts. ORDER PART NMBER LTCCMS LTCCMS-. LTCCMS- LTCIMS LTCIMS-. LTCIMS- MS PART MARKING LTER LTGT LTGV LTHM LTG LTGW SHDN FILT/FB* TOP VIEW CPO C S PACKAGE -LEAD PLASTIC SO *PIN = FILT FOR LTC-./LTC- = FB FOR LTC T JMAX = C, θ JA = C/ W ORDER PART NMBER LTCCS LTCCS-. LTCCS- LTCIS LTCIS-. LTCIS- S PART MARKING I I I ELECTRICAL CHARACTERISTICS The denotes specifications that apply over the full operating temperature range, otherwise specifications are T A = C. SHDN = = V; C =.µf; C, C, C =, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX NITS Operating Voltage LTC.. V LTC-.. V LTC-.. V I VIN Shutdown Current SHDN = V µa I VIN Operating Current I OT = ma, Burst Mode TM Operation C to C µa C to C µa FB Input Current LTC, FB =.V na FB Voltage LTC... V Regulated Output Voltage LTC-., I OT = ma... V LTC-, I OT = ma.9.. V Temperature Coefficient ± ppm Charge Pump Oscillator Frequency I OT > µa, =.V to.v khz Burst Mode is a trademark of Linear Technology Corporation.

3 LTC/LTC-./LTC- ELECTRICAL CHARACTERISTICS The denotes specifications that apply over the full operating temperature range, otherwise specifications are T A = C. SHDN = = V; C =.µf; C, C, C =, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX NITS CPO (Charge Pump Output) =.V, I OT = ma Ω Output Resistance = V, I OT = ma Ω =.V, I OT = ma Ω Dropout Voltage (Note ) LTC, I OT = ma, =.V (Note ) mv LTC/LTC-., I OT = ma, =.V mv LTC/LTC-, I OT = ma, = V 9 mv Enable Time I OT = ma ms Output Noise Voltage LTC I OT = ma, Hz f khz, = V µv RMS I OT = ma, Hz f.mhz, = V µv P-P LTC-. I OT = ma, Hz f khz, C FILT = nf µv RMS I OT = ma, Hz f.mhz, C FILT = nf µv P-P LTC- I OT = ma, Hz f khz, C FILT = nf µv RMS I OT = ma, Hz f.mhz, C FILT = nf µv P-P Line Regulation = V to V, I OT = ma (Note ) mv Load Regulation I OT = ma to ma mv I OT = ma to ma (Note ) mv Shutdown Resistance SHDN = V, Resistance Measured to Ground, =.V Ω SHDN = V, Resistance Measured to Ground, =.V Ω SHDN Input Threshold =.V to.v.. V SHDN Input Current SHDN = µa SHDN = V µa Note : Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note : The LTCC is guaranteed to meet specified performance from C to C and is designed, characterized and expected to meet these extended temperature limits, but is not tested at C and C. The LTCI is guaranteed to meet the extended temperature limits. Note : Dropout voltage is the minimum input/output voltage required to maintain regulation at the specified output current. In dropout the output voltage will be equal to: V CPO V DROPOT (see Figure ). Note : Operating conditions are limited by maximum junction temperature. The regulated output specification will not apply for all possible combinations of input voltage and output current. When operating at maximum input voltage, the output current range may be limited. When operating at maximum output current, the input voltage range may be limited. Note : Limited by the LDO disable switch point of.. Note : The LTC is set to V. The feedback current is µa.

4 LTC/LTC-./LTC- TYPICAL PERFOR A CE CHARACTERISTICS W RCPO (Ω). CPO Output Resistance vs.... (V) T A = C C =.µf I OT = ma.. V CPO (V) Min and Max V CPO vs 9 T A = C V CPO = ( ) (A) (B) V CPO =.( ) (V) (mv) I OT (ma) Transient Response T A = C = V = V C OT = µf TIME (µs) G (A) THE MAXIMM GENERATED NO LOAD CPO VOLTAGE (B) THE MINIMM ALLOWABLE CPO VOLTAGE, AT FLL LOAD, TO ENSRE THAT THE LDO IS NOT DISABLED G G LTC- Output Noise (BW = Hz to.mhz) Shutdown to Enable Timing Enable to Shutdown Timing SHDN (V) SHDN (V) µv/div µs/div C CPO = C OT = = V I OT = ma T A = C = V C FILT = nf G (V) T A = C = V = V I OT = ma C CPO = C OT = µf µs/div (V) NO LOAD T A = C = V = V C OT = µf ms/div OSCILLATION FREQENCY (khz) Oscillator Frequency vs Temperature = V OPERATING CRRENT (µa) G Operating Current vs (No Load) T A = C LTC-. LTC- LTC G TEMPERATRE ( C) G (V) G

5 TYPICAL PERFOR A CE CHARACTERISTICS W LTC/LTC-./LTC- VOLTAGE (V) Voltage vs Temperature = V I OT = ma LTC- LTC-. LTC TEMPERATRE ( C) G9 VOLTAGE (V) Voltage vs Output Current LTC- LTC-. =.V T A = C OTPT CRRENT (ma) G PIN FNCTIONS (Pin ): Low Noise Regulated Output Voltage. should be bypassed with a µf low ESR capacitor as close to the pin as possible for best performance. The range is.v to.v. SHDN (Pin ): Shutdown Input. A logic low on the SHDN pin puts the part in shutdown mode. A logic high enables the part. To continuously enable the part connect SHDN to. When the part is in shutdown, will be connected to ground via a Ω switch and CPO will be high impedance disconnected from. FB (Pin ) (LTC): The voltage on this pin is compared to the internal reference voltage (.V) by the error amplifier to keep the output in regulation. An external resistor divider is required between and FB to adjust the output voltage. FILT (Pin ) (LTC-./LTC-): This pin is used to filter the internal voltage reference. Typically a nf capacitor is connected from FILT to ground. (Pin ): System Ground. (Pin ): Flying Capacitor Negative Input. (Pin ): Input Voltage,.V to.v. should be bypassed with a µf low ESR capacitor as close to the pin as possible for best performance. A minimum capacitance value of.µf is required. C (Pin ): Flying Capacitor Positive Input. CPO (Pin ): nregulated Charge Pump Output Voltage. Approximately.9( ) at low loads. Bypass with a µf low ESR capacitor. If a minimum enable time is required, the CPO capacitor should be the capacitor.

6 LTC/LTC-./LTC- BLOCK DIAGRA SM W C.µF C C CHARGE PMP AND SLEW CONTROL CLK ENB k CPO C k SHDN POWER- ON RESET khz OSCILLATOR REG B SD k REGEN ENB : LDO C V REF =.V REGEN µa/µa SD Ω FB R R F Figure. LTC Block Diagram

7 BLOCK DIAGRA SM W LTC/LTC-./LTC- C.µF C C CHARGE PMP AND SLEW CONTROL CLK ENB k CPO C k SHDN POWER- ON RESET khz OSCILLATOR REG B SD k FILT REGEN ENB nf k : V REF =.V RA k/.k RB k REGEN LDO µa/µa SD Ω C F Figure. LTC-./LTC- Block Diagram

8 LTC/LTC-./LTC- APPLICATIONS INFORMATION W Operation The LTC uses a switched-capacitor charge pump to generate a CPO voltage of approximately ( ). CPO powers an internal low dropout linear regulator that supplies a regulated output at. Internal comparators are used to sense CPO and voltages for power-up conditioning. The output current is sensed to determine the charge pump operating mode. A trimmed internal bandgap is used as the voltage reference and a trimmed internal oscillator is used to control the charge pump switches. The charge pump is a doubler configuration that uses one external flying capacitor. When enabled, a -phase nonoverlapping clock controls the charge pump switches. At start-up, the LDO is disabled and the load is removed from CPO. When CPO reaches.( ) the LDO is enabled. If CPO falls below.( ) the LDO will be disabled. Generally, the charge pump runs open loop with continuous clocking for low noise. If CPO is greater than.9( ) and I OT is less than µa, the charge pump will operate in Burst Mode operation for increased efficiency but slightly higher output noise. In Burst Mode operation, the clock is disabled when CPO reaches.9( ) and enabled when CPO droops by about mv. The switching frequency is precisely controlled to ensure that the frequency is above khz and at the optimum rate to ensure maximum efficiency. The switch edge rates are also controlled to minimize noise. The effective output resistance at CPO is dependent on the voltage at, CPO and the junction temperature. A low ESR capacitor of µf should be used at CPO for minimum noise. The LDO is used to filter the ripple on CPO and to set an output voltage independent of CPO. is set by an external or internal resistor divider. The LDO requires a capacitor on for stability and improved load transient response. A low ESR capacitor of µf should be used. Output Voltage Selection The LTC-./LTC- versions have internal resistor networks to set the regulated output voltage. The LTC output voltage is set using an external resistor divider (see Figure ). The output voltage is determined using the following formula: =.V( R/R) The output voltage range is.v to.v. Maximum and I OT Calculations The maximum available output voltage and current can be calculated based on the open circuit CPO voltage, the dropout voltage of the LDO and the effective output resistance of the charge pump. The open circuit CPO voltage is approximately ( ) (see Figure ). R CPO V CPO C CPO R DROPOT V DROPOT Figure. Equivalent Circuit F I LOAD C.V OT EXTERNAL LDO IN.V C C C.µF CPO C LTC SHDN FB R k R k C.V V RIPPLE = µv P-P =.V( R/R) F Figure. Powering an Auxiliary Regulator from CPO

9 LTC/LTC-./LTC- APPLICATIONS INFORMATION W The following formula can be used to find the maximum output voltage that may be programmed for a given minimum input voltage and output current load: (MAX) = ()((MIN) ) (I OT )(R CPO ) V DROPOT with the condition that (I OT )(R CPO ) <.. Example: (MIN) = V I OT = ma R CPO(MAX) = Ω Max unloaded CPO voltage = V Loaded CPO voltage = V (ma)(ω) =.V V DROPOT(MAX) =.V (MAX) = (V) (.V) (.V) =.V <.V and (I OT )(R CPO ) <.,.V <.V. For minimum noise applications, the LDO must be kept out of dropout to prevent CPO noise from coupling into. External CPO Loading The CPO output can drive an external load (an LDO, for example). The current required by this additional load will reduce the available current from. If the external load requires ma, then the maximum available current at will be reduced by ma. Short-Circuit and Thermal Protection can be shorted to ground indefinitely. Internal circuitry will limit the output current. If the junction temperature exceeds C, the part will shut down. Excessive power dissipation due to heavy loads will also cause the part to shut down when the junction temperature exceeds C. The part will become enabled when the junction temperature drops below C. If the fault condition remains in place, the part will cycle between the shutdown and enabled states. Capacitor Selection For best performance it is recommended that low ESR capacitors be used for C, C and C in Figure to reduce noise and ripple. C must be µf and C must be equal to or greater than C. C is dependent on the source impedance. The charge pump demands large instantaneous currents which may induce ripple onto a common voltage rail. C should be µf and a spike reducing resistor of.ω may be required between and the supply. A low ESR ceramic capacitor is recommended for the flying capacitor C with a value of.µf. At low load or high a smaller capacitor could be used to reduce ripple on CPO which would reflect as lower ripple on. If a minimum enable time is required, the CPO output filter capacitor should be at least the filter capacitor. When the LDO is first enabled, the CPO capacitor will dump a large amount of charge into the capacitor. If the drop in the CPO voltage falls below.( ), the LDO will be disabled and the CPO voltage will have to charge up to.( ) to enable the LDO. The resulting cycling extends the enable time. A nf filter capacitor for the LTC-./LTC- should be connected between the FILT pin and ground for optimum noise performance. Output Ripple The output noise and ripple on CPO includes a spike component from the charge pump switches and a droop component which is dependent on the load current and the value of C. The charge pump has been carefully designed to minimize the spike component; however, low ESR capacitors are essential to reduce the remaining spike energy effect on the CPO voltage. C should be increased for high load currents to minimize the droop component. Ripple components on CPO are greatly reduced at by the LDO; however, C should also be a low ESR capacitor to improve filtering of the CPO noise. Shutdown When SHDN pin is pulled low (<.V), the part will be in shutdown, the supply current will be < µa and will be connected to ground through a Ω switch. In addition, CPO will be high impedance and disconnected from. If shutdown is not required, connect SHDN to which will continuously enable the part. 9

10 LTC/LTC-./LTC- APPLICATIONS INFORMATION Power-On Reset W pon initial power-up, a power-on reset circuit ensures that the internal functions are correctly initialized when power is applied. Once reaches approximately V, the power-on reset circuit will enable the part as long as the SHDN pin is held high. Thermal Considerations The power handling capability of the device will be limited by the maximum rated junction temperature ( C). The device power dissipation P D = I OT ( ) (ma). The device dissipates the majority of its heat through its pins, especially (Pin ). Thermal resistance to ambient can be optimized by connecting to a large copper region on the PCB, which serves as a heat sink. Applications which operate the LTC near maximum power levels should maximize the copper area at all pins except C, and FILT/FB and ensure that there is some airflow over the part to carry away excess heat. General Layout Considerations Due to the high switching frequency and high transient currents produced by the device, careful board layout is a must. A clean board layout using a ground plane and short connections to all capacitors will improve noise performance and ensure proper regulation (Figure ). The FILT pin on the LTC-./LTC- is a high impedance node. Leakage currents at this pin must be minimized. Measuring Output Noise Measuring the LTC low noise levels requires care. Figure shows a test setup for taking the measurement. Good connection and signal handling technique should yield about µv P-P over a.mhz bandwidth. The noise measurement involves AC coupling the LTC output into the test setup s input and terminating this connection with Ω. Coaxial connections must be maintained to preserve measurement integrity. C C SHDN C FILT LTC-./ C C Figure F BATTERY OR LOW NOISE DC POWER SPPLY LTC DEMO BOARD CONNECT BNC AND R LOAD GROND TO THE OTPT CAPACITOR GROND TERMINAL E BNC CABLES OR COPLERS COPLING CAPACITOR R LOAD R* PLACE COPLING CAPACITOR IN SHIELDED BOX WITH COAXIAL CONNECTOR R* PREAMPLIFIER db R* *Ω TERMINATIONS HP-C OR EQIVALENT BANDWIDTH FILTER INPT NOTE: KEEP BNC CONNECTIONS AS SHORT AS POSSIBLE OSCILLOSCOPE F PLACE BANDWIDTH FILTER COMPONENTS IN SHIELDED BOX WITH COAXIAL CONNECTORS Figure. LTC Noise Measurement Test Setup

11 LTC/LTC-./LTC- TYPICAL APPLICATION.V to Low Noise.V Converter SHTDOWN.V C C C.µF CPO C SHDN LTC-. FILT C FILT nf C.V V RIPPLE = µv P-P TA PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted.. (.). ±. (. ±.) TYP SEATING PLANE MS Package -Lead Plastic MSOP (LTC DWG # --). ±. (. ±.). (.) REF. (.) TYP. ±. (. ±.). ±. (. ±.) * DIMENSION DOES NOT INCLDE MOLD FLASH, PROTRSIONS OR GATE BRRS. MOLD FLASH, PROTRSIONS OR GATE BRRS SHALL NOT EXCEED." (.mm) PER SIDE ** DIMENSION DOES NOT INCLDE INTERLEAD FLASH OR PROTRSIONS. INTERLEAD FLASH OR PROTRSIONS SHALL NOT EXCEED." (.mm) PER SIDE. ±.* (. ±.).9 ±. (. ±.). ±.** (. ±.) MSOP (MS) 9 S Package -Lead Plastic Small Outline (Narrow.) (LTC DWG # --).9.9* (..).. (..).. (..) TYP..9 (..).. (..) (..) * DIMENSION DOES NOT INCLDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED." (.mm) PER SIDE ** DIMENSION DOES NOT INCLDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED." (.mm) PER SIDE. (.) TYP.. (.9.9)..** (..9) SO 99

12 LTC/LTC-./LTC- TYPICAL APPLICATION Wide Input Range VCO Supply ( >.V) V TO V V (REQIRED FOR START-P) Q FMMT9 D N C C.µF C CPO C LTC- SHDN FILT R Ω SHTDOWN C FILT nf V LOW NOISE C VCO ta RELATED PARTS PART NMBER DESCRIPTION COMMENTS LTC Low Noise, Voltage-Boosted Varactor Driver Generates V Varactor Drive from V Supply LTC-X Micropower, Regulated Charge Pump Doubler in SOT- I CC = µa; Short Circuit/Thermal Protected LT ma Low Dropout Regulator Micropower; Good Transient Response LTC Micropower, Regulated V Charge Pump ltralow Power: Typical Operating I CC = µa LT Series ma Low Noise LDO Regulator in SOT- I CC = µa; µv RMS Output Noise Linear Technology Corporation McCarthy Blvd., Milpitas, CA 9- () -9 FAX: () - fs, sn LT/TP 99 K PRINTED IN SA LINEAR TECHNOLOGY CORPORATION 999

LTC1515 Series Step-Up/Step-Down Switched Capacitor DC/DC Converters with Reset DESCRIPTION FEATURES APPLICATIONS TYPICAL APPLICATION

LTC1515 Series Step-Up/Step-Down Switched Capacitor DC/DC Converters with Reset DESCRIPTION FEATURES APPLICATIONS TYPICAL APPLICATION LTC Series Step-p/Step-Down Switched Capacitor DC/DC Converters with Reset FEATRES Adjustable/Selectable 3V, 3.3V or V Output Voltages V to V Input Voltage Range p to ma Output Current Only Three External