CAT High Frequency ma CMOS Charge Pump, Inverter/Doubler Description The CAT is a charge pump voltage converter. It can invert a positive input voltage to a negative output. Only two external capacitors are needed. With a guaranteed ma output current capability, the CAT can replace a switching regulator and its inductor. Lower EMI is achieved due to the absence of an inductor. In addition, the CAT can double a voltage supplied from a battery or power supply. Inputs from. V to. V will yield a doubled, V to V output. A Frequency Control pin (BOOST/FC) is provided to select either a high (typically khz) or low ( khz) internal oscillator frequency, thus allowing quiescent current vs. capacitor size trade offs to be made. The khz frequency is selected when the FC pin is connected to V. The operating frequency can also be adjusted with an external capacitor at the pin or by driving with an external clock. pin SOIC package is available. For die availability, contact ON Semiconductor marketing. The CAT can replace the MAX and the LTC in applications where higher oscillator frequency and smaller capacitors are needed. In addition, the CAT is pin compatible with the /, offering an easy upgrade for applications with ma loads. Features Converts V to V or V to V Low Output Resistance, Max. High Power Efficiency Selectable Charge Pump Frequency of khz or khz; Optimize Capacitor Size Low Quiescent Current Pin compatible to MAX, LTC with Higher Frequency Operation Available in pin SOIC Package These Devices are Pb Free, Halogen Free/BFR Free and are RoHS Compliant Applications Negative Voltage Generator Voltage Doubler Voltage Splitter Low EMI Power Source GaAs FET Biasing Lithium Battery Power Supply Instrumentation LCD Contrast Bias Cellular Phones, Pagers BOOST/FC CAP CAP SOIC V SUFFIX CASE BD PIN CONFIGURATION (Top View) V OUT Device Package Shipping CATEVA GT MARKING DIAGRAMS CATEVA CATEVA = CATEVA GT ORDERING INFORMATION SOIC (Pb Free), / Tape & Reel. All packages are RoHS compliant (Lead free, Halogen free).. For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD/D.. For detailed information and a breakdown of device nomenclature and numbering systems, please see the ON Semiconductor Device Nomenclature document, TND/D, available at www.onsemi.com Semiconductor Components Industries, LLC, July, Rev. Publication Order Number: CAT/D
CAT Typical Application V IN. V to. V BOOST/FC V F to BOOST/FC V Inverted F CAP CAP C CAT Negative C CAT Voltage F to Output V IN =. V F CAP OUT to. V CAP OUT C F to F C Doubled Positive Voltage Output F to F Figure. Voltage Inverter Figure. Positive Voltage Doubler Table. PIN DESCRIPTIONS Circuit Configuration Pin Number Name Inverter Mode Doubler Mode Boost/FC Frequency Control for the internal oscillator. With an external oscillator BOOST/FC has no effect. Same as inverter. Boost/FC Oscillator Frequency Oscillator Frequency Open khz typical, khz minimum khz typical V khz typical, khz minimum khz typical, khz minimum CAP Charge Pump Capacitor. Positive terminal. Same as inverter. Power Supply Ground. Power supply. Positive voltage input. CAP Charge pump capacitor. Negative terminal. Same as inverter. OUT Output for negative voltage. Power supply ground. Low Voltage selection pin. When the input voltage is less than V, connect to. For input voltages above V, may be connected to or left open. If is driven externally, connect to. must be tied to OUT for all input voltages. Oscillator control input. An external capacitor can be connected to lower the oscillator frequency. An external oscillator can drive and set the chip operating frequency. The charge pump frequency is one half the frequency at. Same as inverter. Do not overdrive in doubling mode. Standard logic levels will not be suitable. See the applications section for additional information. V Power supply. Positive voltage input. Positive voltage output.
CAT Table. ABSOLUTE MAXIMUM RATINGS Parameters Ratings Units V to V Input Voltage (Pins, and ). to (V.) V BOOST/FC and Input Voltage The least negative of (Out. V) or (V V) to (V. V) V Output Short circuit Duration to (OUT may be shorted to for sec without damage but shorting OUT to V should be avoided.) sec. Continuous Power Dissipation (T A = C) Plastic DIP SO TDFN mw mw W Storage Temperature to C Lead Soldering Temperature ( sec) C ESD Rating Human Body Model V Operating Ambient Temperature Range to C Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. NOTE: T A = Ambient Temperature Table. ELECTRICAL CHARACTERISTICS (V = V, C = C = F, Boost/FC = Open, C = pf, and Test Circuit is Figure unless otherwise noted. Temperature is T A = T AMIN to T AMAX unless otherwise noted.) Parameter Symbol Conditions Min Typ Max Units Supply Voltage VS Inverter: = Open, R L = k.. V Inverter: =, R L = k.. Doubler: = OUT, R L = k.. Supply Current IS BOOST/FC = open, = Open.. ma BOOST/FC = V, = Open Output Current IOUT OUT is more negative than V ma Output Resistance RO C = C = F BOOST/FC = V (C, C ESR. ). C = C = F (Note ). Oscillator Frequency (Note ) F BOOST/FC = Open khz BOOST/FC = V Input Current I BOOST/FC = Open BOOST/FC = V ± ± A Power Efficiency PE R L = k connected between V and OUT, T A = C (Doubler) R L = connected between and OUT, T A = C (Inverter) 9 9 % 9 9 I L = ma to, T A = C (Inverter) Voltage Conversion Efficiency VEFF No load, T A = C 99 99.9 %. In Figure, test circuit electrolytic capacitors C and C are F and have. maximum ESR. Higher ESR levels may reduce efficiency and output voltage.. The output resistance is a combination of the internal switch resistance and the external capacitor ESR. For maximum voltage and efficiency keep external capacitor ESR under... F is tested with C = pf to minimize test fixture loading. The test is correlated back to C = pf to simulate the capacitance at when the device is inserted into a test socket without an external C.
CAT Voltage Inverter CAT V C F BOOST/FC V CAP I S V V C External Oscillator R L CAP OUT I L C F V OUT Figure. Test Circuit Voltage Inverter TYPICAL OPERATING CHARACTERISTICS (Typical characteristic curves are generated using the test circuit in Figure. Inverter test conditions are: V = V, =, BOOST/FC = Open and T A = C unless otherwise indicated. Note that the charge pump frequency is one half the oscillator frequency.) INPUT CURRENT ( A) FC = V FC = open INPUT CURRENT ( A) VIN = V VIN = V VIN = V INPUT VOLTAGE (V) TEMPERATURE ( C) Figure. Supply Current vs. Input Voltage Figure. Supply Current vs. Temperature (No Load) OUTPUT RESISTANCE ( ) OUTPUT RESISTANCE ( ) VIN = V VIN = V VIN = V INPUT VOLTAGE (V) Figure. Output Resistance vs. Input Voltage TEMPERATURE ( C) Figure. Output Resistance vs. Temperature ( Load)
CAT TYPICAL OPERATING CHARACTERISTICS.. INV. OUTPUT VOLTAGE (V).... OUTPUT VOLTAGE (V).... V = V V = V. LOAD CURRENT (ma) LOAD CURRENT (ma) Figure. Inverted Output Voltage vs. Load, V = V Figure 9. Output Voltage Drop vs. Load Current FREQUENCY (khz) FC = Open FREQUENCY (khz) FC = V SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) Figure. Oscillator Frequency vs. Supply Voltage Figure. Oscillator Frequency vs. Supply Voltage, V = V No Load 9 INPUT CURRENT ( A), EFFICIENCY (%) V = V, 9 ILLATOR FREQUENCY (khz) LOAD CURRENT (ma) Figure. Supply Current vs. Oscillator Frequency Figure. Efficiency vs. Load Current
CAT Voltage Doubler CAT V BOOST/FC V V V OUT C F V V CAP CAP OUT External Oscillator C μf Figure. Test Circuit Voltage Doubler TYPICAL OPERATING CHARACTERISTICS (Typical characteristic curves are generated using the circuit in Figure. Doubler test conditions are: V = V, =, BOOST/FC = Open and T A = C unless otherwise indicated.) INPUT CURRENT ( A) FC = V FC = open OUTPUT RESISTANCE ( ) INPUT VOLTAGE (V) Figure. Supply Current vs. Input Voltage (No Load) INPUT VOLTAGE (V) Figure. Output Resistance vs. Input Voltage,. INPUT CURRENT ( A), No Load OUTPUT VOLTAGE (V).... V = V V = V, ILLATOR FREQUENCY (khz) Figure. Supply Current vs. Oscillator Frequency LOAD CURRENT (ma) Figure. Output Voltage Drop vs. Load Current
CAT Application Information Circuit Description and Operating Theory The CAT switches capacitors to invert or double an input voltage. Figure 9 shows a simple switch capacitor circuit. In position capacitor C is charged to voltage V. The total charge on C is Q = CV. When the switch moves to position, the input capacitor C is discharged to voltage V. After discharge, the charge on C is Q = CV. The charge transferred is: Q Q Q C (V V) If the switch is cycled F times per second, the current (charge transfer per unit time) is: I F Q F C (V V) Rearranging in terms of impedance: I (V V) ( FC) V V REQ The /FC term can be modeled as an equivalent impedance REQ. A simple equivalent circuit is shown in Figure. This circuit does not include the switch resistance nor does it include output voltage ripple. It does allow one to understand the switch capacitor topology and make prudent engineering tradeoffs. For example, power conversion efficiency is set by the output impedance, which consists of REQ and switch resistance. As switching frequency is decreased, REQ, the /FC term, will dominate the output impedance, causing higher voltage losses and decreased efficiency. As the frequency is increased quiescent current increases. At high frequency this current becomes significant and the power efficiency degrades. The oscillator is designed to operate where voltage losses are a minimum. With external F capacitors, the internal switch resistances and the Equivalent Series Resistance (ESR) of the external capacitors determine the effective output impedance. A block diagram of the CAT is shown in Figure. V REQ V V V C C R L C R L REQ FC Figure 9. Switched Capacitor Building Block Figure. Switched Capacitor Equivalent Circuit
CAT Oscillator Frequency Control The switching frequency can be raised, lowered or driven from an external source. Figure shows a functional diagram of the oscillator circuit. The CAT oscillator has four control modes: Table. BOOST/FC Pin Connection Pin Connection Nominal Oscillator Frequency Open Open khz BOOST/FC = V Open khz Open or BOOST/FC = V External Capacitor Open External Clock Frequency of external clock If BOOST/FC and are left floating (Open), the nominal oscillator frequency is khz. The pump frequency is one half the oscillator frequency. By connecting the BOOST/FC pin to V, the charge and discharge currents are increased, and the frequency is increased by approximately times. Increasing the frequency will decrease the output impedance and ripple currents. This can be an advantage at high load currents. Increasing the frequency raises quiescent current but allows smaller capacitance values for C and C. If pin,, is loaded with an external capacitor the frequency is lowered. By using the BOOST/FC pin and an external capacitor at, the operating frequency can be set. Note that the frequency appearing at CAP or CAP is one half that of the oscillator. Driving the CAT from an external frequency source can be easily achieved by driving Pin and leaving the BOOST pin open, as shown in Figure. The output current from Pin is small, typically A to A, so a CMOS can drive the pin. For V applications, a TTL logic gate can be used if an external kω pull up resistor is used as shown in Figure. BOOST/FC x () () V () SW CAP () CAP () C SW VOUT () () CLOSED WHEN V >. V Figure. CAT Block Diagram () C (N) = Pin Number
CAT Capacitor Selection Low ESR capacitors are necessary to minimize voltage losses, especially at high load currents. The exact values of C and C are not critical but low ESR capacitors are necessary. The ESR of capacitor C, the pump capacitor, can have a pronounced effect on the output. C currents are approximately twice the output current and losses occur on both the charge and discharge cycle. The ESR effects are thus multiplied by four. A. Ω ESR for C will have the same effect as a Ω increase in CAT output impedance. Output voltage ripple is determined by the value of C and the load current. C is charged and discharged at a current roughly equal to the load current. The internal switching frequency is one half the oscillator frequency. VRIPPLE IOUT (F C) IOUT ESRC For example, with a khz oscillator frequency (. khz switching frequency), a F C capacitor with an ESR of. Ω and a ma load peak to peak ripple voltage is mv. Table. VRIPPLE vs. F VRIPPLE (mv) IOUT (ma) F (khz) C ( F) C ESR ( ).. V BOOST/FC () (). I. I I I () ~ pf C NC REQUIRED FOR TTL LOGIC V CAT k BOOST/FC V INPUT CAP CAP OUT V C Figure. Oscillator Figure. External Clocking 9
Capacitor Suppliers The following manufacturers supply low ESR capacitors: Table. CAPACITOR SUPPLIERS CAT Manufacturer Capacitor Type Phone WEB Email Comments AVX/Kyocera TPS/TPS 9 www.avxcorp.com avx@avxcorp.com Tantalum Vishay/Sprague 9 www.vishay.com Aluminum Sanyo MV AX, UGX 9 www.sanyo.com Svcsales@sanyo.com Aluminum Nichicon F www.nichicon us.com Tantalum HC/HD Aluminum Capacitor manufacturers continually introduce new series and offer different package styles. It is recommended that before a design is finalized capacitor manufacturers should be surveyed for their latest product offerings. Controlling Loss in CAT Applications There are three primary sources of voltage loss:. Output resistance: VLOSS = ILOAD x ROUT, where ROUT is the CAT output resistance and ILOAD is the load current.. Charge pump (C) capacitor ESR: VLOSSC x ESRC x ILOAD, where ESRC is the ESR of capacitor C.. Output or reservoir (C) capacitor ESR: VLOSSC = ESRC x ILOAD, where ESRC is the ESR of capacitor C. Increasing the value of C and/or decreasing its ESR will reduce noise and ripple. The effective output impedance of a CAT circuit is approximately: Rcircuit Rout ( ESRC) ESRC
CAT Typical Applications Voltage Inversion Positive to Negative The CAT easily provides a negative supply voltage from a positive supply in the system. Figure shows a typical circuit. The pin may be left floating for positive input voltages at or above. V. CAT C NC BOOST/FC V CAP CAP OUT V IN. V to. V V OUT = V IN C Figure. Voltage Inverter Positive Voltage Doubler The voltage doubler circuit shown in Figure gives V OUT = x V IN for input voltages from. V to. V. N* CAT C F BOOST/FC CAP V C F V OUT = V IN V IN. V to. V CAP OUT *SCHOTTKY DIODE IS FOR START UP ONLY Figure. Voltage Doubler
CAT Precision Voltage Divider A precision voltage divider is shown in Figure. With load currents under na, the voltage at pin will be within.% of V/. CAT C F BOOST/FC V CAP CAP OUT V V to V V ±.% I L na C F Figure. Precision Voltage Divider (Load na) Battery Voltage Splitter Positive and negative voltages that track each other can be obtained from a battery. Figure shows how a 9 V battery can provide symmetrical positive and negative voltages equal to one half the battery voltage. CAT BATTERY 9 V V V BAT V V BAT C F BOOST/FC V CAP CAP OUT V BAT (. V) V BAT (. V) C F Figure. Battery Splitter
CAT Cascade Operation for Higher Negative Voltages The CAT can be cascaded as shown in Figure to generate more negative voltage levels. The output resistance is approximately the sum of the individual CAT output resistance. V OUT = N x V IN, where N represents the number of cascaded devices. V IN C CAT CN CAT N C C V OUT = NV IN Figure. Cascading to Increase Output Voltage Parallel Operation Paralleling CAT devices will lower output resistance. As shown in Figure 9, each device requires its own pump capacitor, C, but the output reservoir capacitor is shared with all devices. The value of C should be increased by a factor of N, where N is the number of devices. ROUT ROUT (of CAT) N (NUMBER OF DEVICES) V IN C CAT CN CAT N C Figure 9. Reduce Output Resistance BY Paralleling Devices
CAT PACKAGE DIMENSIONS SOIC, mils CASE BD ISSUE O SYMBOL MIN NOM MAX A.. A.. b.. E E c D.9... E.. E.. e. BSC h.. PIN # IDENTIFICATION L.. θ º º TOP VIEW D h A A θ c e b L SIDE VIEW END VIEW Notes: () All dimensions are in millimeters. Angles in degrees. () Complies with JEDEC MS-. ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of SCILLC s product/patent coverage may be accessed at www.onsemi.com/site/pdf/patent Marking.pdf. SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. Typical parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including Typicals must be validated for each customer application by customer s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner. PUBLICATION ORDERING INFORMATION LITERATURE FULFILLMENT: Literature Distribution Center for ON Semiconductor P.O. Box, Denver, Colorado USA Phone: or Toll Free USA/Canada Fax: or Toll Free USA/Canada Email: orderlit@onsemi.com N. American Technical Support: 9 Toll Free USA/Canada Europe, Middle East and Africa Technical Support: Phone: 9 9 Japan Customer Focus Center Phone: ON Semiconductor Website: www.onsemi.com Order Literature: http://www.onsemi.com/orderlit For additional information, please contact your local Sales Representative CAT/D