TK11812 DC-DC CONVERTER APPLICATIONS FEATURES DESCRIPTION TK11812M ORDERING INFORMATION

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1 TK8 DC-DC CONERTER FEATURES Miniature Package (SOT-L) Low Start-up oltage [.6 (typ.)] Few External Components Adjustable Output oltage (. to ) Wide Input oltage Range (.6 to ) APPLICATIONS Pagers Cassette Recorders Cordless Telephones Portable Instrumentation Radio Control Systems Mobile Radios Battery Operated Equipment Local Area Network (LAN) Receivers DESCRIPTION The TK8 is a low power, low input voltage step-up DC-DC converter. TK8 This device can be set to an output of. to DC using two resistors. The output current is dependent upon the input voltage and ranges from 8 ma at.6 to ma at.. The efficiency is over 8% for an output current of ma to ma with a. input and output. P IN FB FB The frequency of the built-in relaxation oscillator is set by external components. The internal voltage regulator provides a stable output voltage. Optimized Toko inductor components are available. OSC The TK8 is available in a miniature 6-pin SOT-L surface mount package. BLOCK DIAGRAM IN FB OSC ORDERING INFORMATION TK8M ref Tape/Reel Code OSCILLATOR - + FB TAPE/REEL CODE TL: Tape Left June 999 TOKO, Inc. Page

2 TK8 ABSOLUTE MAXIMUM RATINGS Input oltage... 6 Output oltage... Power Dissipation (Note )... mw Junction Temperature... C Storage Temperature Range... - to + C Operating Temperature Range...- to +6 C Lead Soldering Temperature ( s)... C TK8 ELECTRICAL CHARACTERISTICS Test Conditions: T A = C, =., unless otherwise specified. SYMBOL PARAMETER TEST CONDITIONS MIN TYP MAX UNITS I IN I START Line Load EFF F OSC Reg Reg Supply oltage Range. 6 Start-up oltage I = ma. 6.7 Input Current Output oltage Output Current =., I = ma 6 ma =., I = ma 8. ma =., I = ma, (Note ).8.. O UT =., I = ma, (Note ).8.. O UT =... ma = ma Line Regulation I = ma,. IN. m Load Regulation Efficiency Oscillator Frequency O UT / T Temperature Coefficient ref Reference oltage =.,. ma I ma m =., I = ma 6 7 % =., I = ma (Note ) khz O UT =., I = ma. m/ C =., I = ma, (Note ). O UT Note : Power dissipation is mw when mounted as recommended. Derate at. mw/ C for operation above C. Power dissipation is mw when in Free Air. Derate at.6 mw/ C for operation above C. Note : This IC is a frequency-controlled DC-DC converter, thus, the value is varied by condition. Note : Output with R /R set for. nominal. Note : Reference voltage is measured at FB pin (pin 6). Page June 999 TOKO, Inc.

3 TK8 TEST CIRCUIT R R + µf µf + KΩ IN Note: Di: IS87,8, or equivalent L: Toko 9KN-69AQ Toko PSCDL-69X L Di C pf R KΩ Note: = ref [ + (R / R )] ref =. R = k to k ref is the FB pin voltage. 6 TYPICAL PERFORMANCE CHARACTERISTICS T A = C, unless otherwise specified. PUT OLTAGE S. PUT CURRENT ( =. ) EFFICIENCY S. PUT CURRENT ( =. ) PUT OLTAGE S. PUT CURRENT ( =. ) () IN = IN = () IN = EFFICIENCY S. PUT CURRENT ( =. ) PUT OLTAGE S. PUT CURRENT ( =. ) EFFICIENCY S. PUT CURRENT ( =. ) IN = () IN = IN = June 999 TOKO, Inc. Page

4 TK8 TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) T A = C, unless otherwise specified. PUT OLTAGE S. PUT CURRENT ( =. ) EFFICIENCY S. PUT CURRENT ( =. ) PUT OLTAGE S. PUT CURRENT ( =. ).6. () () IN =...8 IN = IN = EFFICIENCY S. PUT CURRENT ( =. ). QUIESCENT CURRENT S. INPUT OLTAGE + PUT OLTAGE DRIFT S. TEMPERATURE. I Q (µa) = (m) = =. 8 6 I (ma).... () = - - T A ( C) Page June 999 TOKO, Inc.

5 TK8 ADDITIONAL INFORMATION APPLICATION INFORMATION Maximize copper foil area connecting to all IC pins for optimum performance. Place input and output bypass capacitors close to the pin. For best transient behavior and lowest output impedance, use as large of a capacitor value as possible. The temperature coefficient of the capacitance and Equivalent Series Resistance (ESR) should be taken into account. These parameters can influence power supply noise and ripple rejection. In extreme cases, oscillation may occur. In order to maintain stability the output bypass capacitor value should be a minimum of µf in the case of tantalum electrolytic, or µf in the case of aluminum electrolytic. HANDLING MOLDED RESIN PACKAGES All plastic molded packages absorb some moisture from the air. If moisture absorption occurs prior to soldering the device into the printed circuit board, increased separation of the lead from the plastic molding may occur, degrading the moisture barrier characteristics of the device. This property of plastic molding compounds should not be overlooked, particularly in the case of very small packages where the plastic is very thin. In order to preserve the original moisture barrier properties of the package, devices are stored and shipped in moisture proof bags filled with dry air. The bags should not be opened or damaged prior to actual use of the devices. If this is unavoidable, the devices should be stored in a low relative humidity environment ( to 6%) or in an enclosed environment with desiccant. INDUCTOR NOTES The output current and efficiency are largely dependent on the coil used. A coil with lower DC resistance is generally better in efficiency than one with a higher DCR (DC Resistance). The recommended TOKO 9KN-69 AQ is a : turns ratio transformer with an inductance of µh, and Toko 9KN-7UG is a : transformer ratio with the inductance of 6 µh: 6 µh. These coils or equivalent should be used. Smaller coils with higher DCR will not perform as well as the above coil, and the oscillator will not be stable. FEEDBACK RC TIME CONSTANT If a different coil is used other than the one mentioned, the RC time constant of the feedback loop will need to be adjusted for optimum performance. Generally, a lower resistance will give more output current. In fact, R can be zero; however, lower resistance will sacrifice efficiency at low output currents as the quiescent current increases. If the capacitance is increased beyond or below a certain value, the oscillator will become unstable. The optimum RC values depend upon the operating voltage range, output voltage and operating current, and should be chosen experimentally using the given values of pf and KΩ as a starting point. INPUT/PUT DECOUPLING CAPACITORS DC-DC converters generate a large ripple current on both the input and output of the circuit. The capacitors used should be as large as possible and have low impedance in the khz range. Since low temperatures cause capacitors to decrease capacitance and increase Equivalent Series Resistance (ESR) care should be taken to choose capacitors that have acceptable characteristics over the temperature range you intend to use. This should be done experimentally to verify results, as capacitor performance varies widely from manufacturer to manufacturer. Tantalum capacitors are generally the best choice and µf should be adequate for most applications. LOAD CHARACTERISTICS The TK8 should not be allowed to start up under full load conditions. If this occurs, the output may not stabilize to the correct output voltage. This can be compensated for, somewhat, by adjusting the RC of the feedback loop or by decreasing the output decoupling capacitor. Maximum current can be drawn after the oscillator has started and the output has reached nominal output voltage. This is more critical with input voltages under. as the converter needs to generate sufficient output to ensure correct internal bandgap and bias voltages. June 999 TOKO, Inc. Page

6 TK8 EALUATION BOARD LAY CA L IN R K C pf K µf TK8x D µf AP-99 R R TOKO IN AP-99 TOKO Page 6 June 999 TOKO, Inc.

7 TK8 NOTES June 999 TOKO, Inc. Page 7

8 TK8 PACKAGE LINE SOT-L (SOTL-6) Marking Information TK8 Marking D.6 6 Marking. e. e e M e.9 e.9 Recommended Mount Pad (.). Dimensions are shown in millimeters Tolerance: x.x = ±. mm (unless otherwise specified). max max. Toko America, Inc. Headquarters Feehanville Drive, Mount Prospect, Illinois 66 Tel: (87) 97-7 Fax: (87) TOKO AMERICA REGIONAL OFFICES Midwest Regional Office Toko America, Inc. Feehanville Drive Mount Prospect, IL 66 Tel: (87) 97-7 Fax: (87) Western Regional Office Toko America, Inc. 8 North First Street, Suite 6 San Jose, CA 9 Tel: (8) -88 Fax: (8) Eastern Regional Office Toko America, Inc. 7 Mill Plain Road Danbury, CT 68 Tel: () Fax: () 797- Semiconductor Technical Support Toko Design Center 7 Forge Road Colorado Springs, CO 897 Tel: (79) 8- Fax: (79) 8-7 isit our Internet site at The information furnished by TOKO, Inc. is believed to be accurate and reliable. However, TOKO reserves the right to make changes or improvements in the design, specification or manufacture of its products without further notice. TOKO does not assume any liability arising from the application or use of any product or circuit described herein, nor for any infringements of patents or other rights of third parties which may result from the use of its products. No license is granted by implication or otherwise under any patent or patent rights of TOKO, Inc. Page Toko, Inc. All Rights Reserved IC--TK8 798O.K June 999 TOKO, Inc. Printed in the USA

TK716xx LOW DROPOUT VOLTAGE REGULATOR FEATURES APPLICATIONS DESCRIPTION ORDERING INFORMATION TK716 SCL TK716 S I L TK716 SCL H

TK716xx LOW DROPOUT VOLTAGE REGULATOR FEATURES APPLICATIONS DESCRIPTION ORDERING INFORMATION TK716 SCL TK716 S I L TK716 SCL H LOW DROP OLTAGE REGULATOR FEATURES Available in ± 2. % or ± 1. % Output Tolerance Active High On/Off Control ery Low Quiescent Current ery Low Dropout oltage Reverse Bias Protection Miniature Package (SOT23-5)