Datasheet ADP1878, ADP1879 (Analog Devices) - 2
| Hersteller | Analog Devices |
| Beschreibung | Synchronous Buck Controller with Constant On-Time and Valley Current Mode with Power Saving Mode |
| Seiten / Seite | 40 / 2 — ADP1878/ADP1879. Data Sheet. TABLE OF CONTENTS. REVISION HISTORY … |
| Revision | B |
| Dateiformat / Größe | PDF / 2.0 Mb |
| Dokumentensprache | Englisch |
ADP1878/ADP1879. Data Sheet. TABLE OF CONTENTS. REVISION HISTORY 9/12—Rev. A to Rev. B. 6/12—Rev. 0 to Rev. A
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ADP1878/ADP1879 Data Sheet TABLE OF CONTENTS
Features .. 1 Pseudo Fixed Frequency.. 22 Applications ... 1 Power-Good Monitoring ... 23 Typical Applications Circuit .. 1 Applications Information .. 24 General Description ... 1 Feedback Resistor Divider .. 24 Revision History ... 2 Inductor Selection .. 24 Specifications ... 3 Output Ripple Voltage (ΔVRR) .. 24 Absolute Maximum Ratings ... 5 Output Capacitor Selection... 24 Thermal Resistance .. 5 Compensation Network .. 25 ESD Caution .. 5 Efficiency Consideration ... 26 Pin Configuration and Function Descriptions ... 6 Input Capacitor Selection .. 27 Typical Performance Characteristics ... 7 Thermal Considerations .. 27 Theory of Operation .. 17 Design Example .. 29 Block Diagram .. 17 External Component Recommendations .. 31 Startup .. 18 Layout Considerations ... 33 Soft Start .. 18 IC Section (Left Side of Evaluation Board) ... 35 Precision Enable Circuitry .. 18 Power Section ... 35 Undervoltage Lockout ... 18 Differential Sensing .. 36 On-Board Low Dropout (LDO) Regulator ... 18 Typical Application Circuits ... 37 Thermal Shutdown ... 19 12 A, 300 kHz High Current Application Circuit .. 37 Programming Resistor (RES) Detect Circuit .. 19 5.5 V Input, 600 kHz Current Application Circuit .. 37 Valley Current-Limit Setting .. 19 300 kHz High Current Application Circuit .. 38 Hiccup Mode During Short Circuit ... 21 Packaging and Ordering Information ... 39 Synchronous Rectifier .. 21 Outline Dimensions ... 39 ADP1879 Power Saving Mode (PSM) .. 21 Ordering Guide .. 40 Timer Operation ... 22
REVISION HISTORY 9/12—Rev. A to Rev. B
Changes to Table 7 ... 20
6/12—Rev. 0 to Rev. A
Changes to Table 1 ... 3
7/11—Revision 0: Initial Version
Rev. B | Page 2 of 40 Document Outline Features Applications Typical Applications Circuit General Description Revision History Specifications Absolute Maximum Ratings Thermal Resistance Boundary Condition ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Theory of Operation Block Diagram Startup Soft Start Precision Enable Circuitry Undervoltage Lockout On-Board Low Dropout (LDO) Regulator Thermal Shutdown Programming Resistor (RES) Detect Circuit Valley Current-Limit Setting Hiccup Mode During Short Circuit Synchronous Rectifier ADP1879 Power Saving Mode (PSM) Timer Operation Pseudo Fixed Frequency Power-Good Monitoring Applications Information Feedback Resistor Divider Inductor Selection Output Ripple Voltage (ΔVRR) Output Capacitor Selection Compensation Network Output Filter Impedance (ZFILT) Error Amplifier Output Impedance (ZCOMP) Error Amplifier Gain (Gm) Current-Sense Loop Gain (GCS) Crossover Frequency Efficiency Consideration Channel Conduction Loss MOSFET Driver Loss MOSFET Switching Loss Body Diode Conduction Loss Inductor Loss Input Capacitor Selection Thermal Considerations Design Example Input Capacitor Inductor Current-Limit Programming Output Capacitor Feedback Resistor Network Setup Compensation Network Loss Calculations External Component Recommendations Layout Considerations IC Section (Left Side of Evaluation Board) Power Section Differential Sensing Typical Application Circuits 12 A, 300 kHz High Current Application Circuit 5.5 V Input, 600 kHz Current Application Circuit 300 kHz High Current Application Circuit Packaging and Ordering Information Outline Dimensions Ordering Guide
ADP1878/ADP1879 Data Sheet TABLE OF CONTENTS
Features .. 1 Pseudo Fixed Frequency.. 22 Applications ... 1 Power-Good Monitoring ... 23 Typical Applications Circuit .. 1 Applications Information .. 24 General Description ... 1 Feedback Resistor Divider .. 24 Revision History ... 2 Inductor Selection .. 24 Specifications ... 3 Output Ripple Voltage (ΔVRR) .. 24 Absolute Maximum Ratings ... 5 Output Capacitor Selection... 24 Thermal Resistance .. 5 Compensation Network .. 25 ESD Caution .. 5 Efficiency Consideration ... 26 Pin Configuration and Function Descriptions ... 6 Input Capacitor Selection .. 27 Typical Performance Characteristics ... 7 Thermal Considerations .. 27 Theory of Operation .. 17 Design Example .. 29 Block Diagram .. 17 External Component Recommendations .. 31 Startup .. 18 Layout Considerations ... 33 Soft Start .. 18 IC Section (Left Side of Evaluation Board) ... 35 Precision Enable Circuitry .. 18 Power Section ... 35 Undervoltage Lockout ... 18 Differential Sensing .. 36 On-Board Low Dropout (LDO) Regulator ... 18 Typical Application Circuits ... 37 Thermal Shutdown ... 19 12 A, 300 kHz High Current Application Circuit .. 37 Programming Resistor (RES) Detect Circuit .. 19 5.5 V Input, 600 kHz Current Application Circuit .. 37 Valley Current-Limit Setting .. 19 300 kHz High Current Application Circuit .. 38 Hiccup Mode During Short Circuit ... 21 Packaging and Ordering Information ... 39 Synchronous Rectifier .. 21 Outline Dimensions ... 39 ADP1879 Power Saving Mode (PSM) .. 21 Ordering Guide .. 40 Timer Operation ... 22
REVISION HISTORY 9/12—Rev. A to Rev. B
Changes to Table 7 ... 20
6/12—Rev. 0 to Rev. A
Changes to Table 1 ... 3
7/11—Revision 0: Initial Version
Rev. B | Page 2 of 40 Document Outline Features Applications Typical Applications Circuit General Description Revision History Specifications Absolute Maximum Ratings Thermal Resistance Boundary Condition ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Theory of Operation Block Diagram Startup Soft Start Precision Enable Circuitry Undervoltage Lockout On-Board Low Dropout (LDO) Regulator Thermal Shutdown Programming Resistor (RES) Detect Circuit Valley Current-Limit Setting Hiccup Mode During Short Circuit Synchronous Rectifier ADP1879 Power Saving Mode (PSM) Timer Operation Pseudo Fixed Frequency Power-Good Monitoring Applications Information Feedback Resistor Divider Inductor Selection Output Ripple Voltage (ΔVRR) Output Capacitor Selection Compensation Network Output Filter Impedance (ZFILT) Error Amplifier Output Impedance (ZCOMP) Error Amplifier Gain (Gm) Current-Sense Loop Gain (GCS) Crossover Frequency Efficiency Consideration Channel Conduction Loss MOSFET Driver Loss MOSFET Switching Loss Body Diode Conduction Loss Inductor Loss Input Capacitor Selection Thermal Considerations Design Example Input Capacitor Inductor Current-Limit Programming Output Capacitor Feedback Resistor Network Setup Compensation Network Loss Calculations External Component Recommendations Layout Considerations IC Section (Left Side of Evaluation Board) Power Section Differential Sensing Typical Application Circuits 12 A, 300 kHz High Current Application Circuit 5.5 V Input, 600 kHz Current Application Circuit 300 kHz High Current Application Circuit Packaging and Ordering Information Outline Dimensions Ordering Guide