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DC/DC Converter

Summary of Contents for SCI 7660 SERIES

Page 1: ...1 DC DC Converter ...

Page 2: ...voltage Low operating voltage On chip RC oscillator 8 pin plastic DIP and 8 pin plastic SOP APPLICATIONS Fixed voltage power supplies for battery operated equipment Power supplies for pagers memory cards calculators and similar hand held equipment Fixed voltage power supplies for medical equipment Fixed voltage power supplies for communications equipment Uninterruptable power supplies BLOCK DIAGRA...

Page 3: ...ices Recommended Operating Conditions VDD 0V Ta 40 to 85 C unless otherwise noted Parameter Symbol Condition Rating Unit Min Typ Max ROSC 1MΩ C1 C2 1 20 C2 10µF 1 5 Oscillator startup voltage VSTA Ta 40 to 85 C V See note 1 ROSC 1MΩ 2 2 Oscillator shutdown voltage VSTP ROSC 1MΩ 1 5 V Load resistance RL RL min Ω See note 2 Output current IO 30 0 mA Clock frequency fOSC 10 0 30 0 kHz RC oscillator n...

Page 4: ...SC 1MΩ 20 30 µA VI 5V Quiescent current IQ RL VI 8V 2 0 µA Clock frequency fOSC ROSC 1MΩ VI 5V 16 20 24 kHz Output impedance RO IO 10mA VI 5V 75 100 Ω Multiplication efficiency Peff IO 5mA VI 5V 90 95 OSC1 Input leakage current ILKI VI 8V 2 0 µA 3 RL min is a function of VI Electrical Characteristics Battery C L D1 C2 22µF C1 10µF R L 1MΩ 8 7 6 5 1 2 3 4 1 0 5 4 3 2 1 0 1 5 2 0 Input voltage V Min...

Page 5: ...18 17 16 15 14 13 12 11 10 9 8 40 20 0 20 40 Ta C f OSC KHz 60 80 100 VI 5 0V VI 3 0V VI 2 0V Clock frequency vs External resistance Clock frequency vs Ambient temperature 50 45 40 35 30 25 20 15 10 5 0 7 6 5 4 3 2 1 0 lopr µA VI V Ta 25 C fOSC 40kHz fOSC 20kHz fOSC 10kHz 0 5 10 15 0 10 20 30 40 50 V O V IO mA Ta 25 VI 5 0V Multiplier current vs Input voltage Output voltage vs Output current ...

Page 6: ...3 0V 0 1 2 3 4 5 6 0 2 3 4 5 6 7 8 9 10 1 V O V IO mA Ta 25 C VI 2 0V Output voltage vs Output current Output voltage vs Output current 300 200 100 0 7 6 5 4 3 2 1 0 R O Ω VI V Ta 25 C IO 7mA 300 200 100 0 7 6 5 4 3 2 1 0 R O Ω VI V Ta 25 C Io 10mA Output impedance vs Input voltage Output impedance vs Input voltage ...

Page 7: ...I 3 0V Multiplication efficiency vs Clock frequency Multiplication efficiency vs Clock frequency 100 90 80 70 60 50 40 30 20 10 0 100 90 80 70 60 50 40 30 20 10 0 0 10 20 30 40 50 Peff I I mA IO mA Ta 25 C VI 5 0V II Peff 100 90 80 70 60 50 40 30 20 10 0 100 90 80 70 60 50 40 30 20 10 0 0 5 10 15 20 25 30 Peff I I mA IO mA Ta 25 C VI 3 0V II Peff Multiplication efficiency input current vs Multipli...

Page 8: ...C2 OSC1 OSC2 External clock signal 100 90 80 70 60 50 40 30 20 10 0 40 36 32 28 24 20 16 12 8 4 0 0 1 2 3 4 5 6 7 8 9 10 Peff I I mA IO mA Ta 25 C VI 2 0V II Peff Multiplication efficiency input current vs Output current Voltage Multiplier The voltage multiplier uses the clock signal from the oscillator to double the input voltage This requires two external capacitors a charge pump capacitor C1 be...

Page 9: ... V VO 10 V 1MΩ 8 7 6 5 1 2 3 4 C1 10µF 1MΩ 8 7 6 5 1 2 3 4 Serial Connection Connecting two or more chips in series obtains a higher output voltage than can be obtained using a parallel connection however this also raises the output imped ance Potential levels 5 V C1 10µF C2 10µF VDD 0 V VI 5 V VO 15 V VO 10 V VI VDD VI 5 1MΩ 8 7 6 5 1 2 3 4 C1 10µF C2 10µF 1MΩ 8 7 6 5 1 2 3 4 VDD 0 V VI 5 V VO 10...

Page 10: ...tage positive 5 V C2 10µF VDD 0 V VO 3 8 V VI 5 V 1MΩ C1 10µF 8 7 6 5 1 2 3 4 Simultaneous Voltage Conversion Combining a multiplier circuit with a positive voltage conversion circuit generates both 10 and 3 8 V outputs from a single input Potential levels 5 V C2 10µF VDD 0 V VO2 3 8 V VO1 10 V VI 5 V 1MΩ C3 C4 10µF 10µF 8 7 6 5 1 2 3 4 C1 10µF VO2 3 8 V VO1 10 V VDD 0 V VI 5 V ...

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