Datasheet LTC7897 (Analog Devices) - 6
| Fabricante | Analog Devices |
| Descripción | 140V, Low IQ, Synchronous Buck Controller with Programmable 5V to 10V Gate Drive in 28-Lead QFN (4mm x 5mm x 0.75mm w/ EP) package |
| Páginas / Página | 53 / 6 — Data Sheet. LTC7897. PARAMETER. SYMBOL. CONDITIONS/COMMENTS. MIN. TYP. … |
| Formato / tamaño de archivo | PDF / 1.6 Mb |
| Idioma del documento | Inglés |
Data Sheet. LTC7897. PARAMETER. SYMBOL. CONDITIONS/COMMENTS. MIN. TYP. MAX. UNITS. Charge Pump for BST-SW Supply
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Data Sheet LTC7897
(Specifications are for TJ = -40°C to +150°C for the minimum and maximum values, TA = 25°C for the typical values, VIN = 12V, RUN = 12V, VPRG = floating, EXTVCC = 0V, DRVSET = 0V, DRVUV = 0V, TGUP = TGDN = TGxx, BGUP = BGDN = BGxx, and DTCA and DTCB = 0V, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS/COMMENTS MIN TYP MAX UNITS
DTCA = 10k 13 ns BGxx Off to TGxx On DTCA = 50k 50 ns Smart Delay
5
DTCA = 100k 100 ns DTCB = 10k 13 ns TGxx Off to BGxx On DTCB = 50k 50 ns Smart Delay
5
DTCB = 100k 100 ns TG Minimum On-Time
6
tON(MIN) 80 ns Maximum Duty Cycle Output in Dropout, FREQ = 0V 100 %
Charge Pump for BST-SW Supply
V Charge Pump Output BST-SW = 7V, V −120 µA Current SW = 0V VSW = 12V −80 µA Charge Pump Output V Voltage BST-SW IBST = −1µA, VSW = 0V and 12V 10 11 12 V
Low Dropout (LDO) Linear Regulators
EXTVCC = INTVCC for VIN LDO, EXTV DRV CC = 12V for EXTVCC LDO CC Voltage for VIN DRVSET = INTV 9.5 9.77 10.0 V and EXTV CC CC LDOs DRVSET = 64.9kΩ 5.8 6.5 7.0 V DRVSET = 0V 5.8 6.0 6.2 V EXTVCC = INTVCC for VIN LDO, EXTV DRV CC = 12V for EXTVCC LDO, CC Load Regulation 1 3 % DRVCC load current = 0mA to 100mA, TA = 25°C DRVCC Rising, EXTVCC = INTVCC DRVUV = INTVCC 7.1 7.4 7.6 V DRVUV = floating 5.2 5.35 5.5 V DRVUV = 0V 3.8 3.93 4.0 V Undervoltage Lockout UVLO DRVCC Falling, EXTVCC = INTVCC DRVUV = INTVCC 6.4 6.64 6.8 V DRVUV = floating 4.9 5.05 5.2 V DRVUV = 0V 3.6 3.71 3.8 V
analog.com
Rev. A 6 of 53 Document Outline Features Applications General Description Typical Application TABLE OF CONTENTS Revision History Specifications Absolute Maximum Ratings Pin Configurations and Function Descriptions Block Diagram Typical Performance Characteristics Theory of Operation Main Control Loop Power and Bias Supplies (VIN, EXTVCC, DRVCC, and INTVCC) High-Side Bootstrap Capacitor Dead Time Control (DTCA and DTCB Pins) Start-Up and Shutdown (RUN, OVLO, and TRACK/SS Pins) Light Load Operation: Burst Mode Operation, Pulse-Skipping Mode, or Forced Continuous Mode (MODE Pin) Frequency Selection, Spread Spectrum, and PhaseLocked Loop (FREQ and PLLIN/SPREAD Pins) Input Supply Overvoltage Lockout (OVLO Pin) Output Overvoltage Protection Foldback Current Power Good Applications Information Inductor Value Calculation Inductor Core Selection Current Sense Selection Low Value Resistor Current Sensing Inductor DCR Current Sensing Setting the Operating Frequency Selecting the Light-Load Operating Mode Dead Time Control (DTCA and DTCB Pins) DTCX Pins Tied to INTVCC or Ground (Adaptive Dead Time Control) DTCX Pin Connected with a Resistor to GND Power MOSFET Selection CIN and COUT Selection Setting the Output Voltage RUN Pin and Overvoltage/Undervoltage Lockout Soft-Start and Tracking (TRACK/SS Pin) DRVCC and INTVCC Regulators (OPTI-DRIVE) Topside MOSFET Driver Supply (CB, DB) Minimum On-Time Considerations Fault Conditions: Current Limit and Foldback Fault Conditions: Overvoltage Protection Fault Conditions: Overtemperature Protection Phase-Locked Loop and Frequency Synchronization Efficiency Considerations Checking Transient Response Design Example PC Board Layout Checklist PC Board Layout Debugging Typical Application Related Parts Outline Dimensions Ordering Guide
Data Sheet LTC7897
(Specifications are for TJ = -40°C to +150°C for the minimum and maximum values, TA = 25°C for the typical values, VIN = 12V, RUN = 12V, VPRG = floating, EXTVCC = 0V, DRVSET = 0V, DRVUV = 0V, TGUP = TGDN = TGxx, BGUP = BGDN = BGxx, and DTCA and DTCB = 0V, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS/COMMENTS MIN TYP MAX UNITS
DTCA = 10k 13 ns BGxx Off to TGxx On DTCA = 50k 50 ns Smart Delay
5
DTCA = 100k 100 ns DTCB = 10k 13 ns TGxx Off to BGxx On DTCB = 50k 50 ns Smart Delay
5
DTCB = 100k 100 ns TG Minimum On-Time
6
tON(MIN) 80 ns Maximum Duty Cycle Output in Dropout, FREQ = 0V 100 %
Charge Pump for BST-SW Supply
V Charge Pump Output BST-SW = 7V, V −120 µA Current SW = 0V VSW = 12V −80 µA Charge Pump Output V Voltage BST-SW IBST = −1µA, VSW = 0V and 12V 10 11 12 V
Low Dropout (LDO) Linear Regulators
EXTVCC = INTVCC for VIN LDO, EXTV DRV CC = 12V for EXTVCC LDO CC Voltage for VIN DRVSET = INTV 9.5 9.77 10.0 V and EXTV CC CC LDOs DRVSET = 64.9kΩ 5.8 6.5 7.0 V DRVSET = 0V 5.8 6.0 6.2 V EXTVCC = INTVCC for VIN LDO, EXTV DRV CC = 12V for EXTVCC LDO, CC Load Regulation 1 3 % DRVCC load current = 0mA to 100mA, TA = 25°C DRVCC Rising, EXTVCC = INTVCC DRVUV = INTVCC 7.1 7.4 7.6 V DRVUV = floating 5.2 5.35 5.5 V DRVUV = 0V 3.8 3.93 4.0 V Undervoltage Lockout UVLO DRVCC Falling, EXTVCC = INTVCC DRVUV = INTVCC 6.4 6.64 6.8 V DRVUV = floating 4.9 5.05 5.2 V DRVUV = 0V 3.6 3.71 3.8 V
analog.com
Rev. A 6 of 53 Document Outline Features Applications General Description Typical Application TABLE OF CONTENTS Revision History Specifications Absolute Maximum Ratings Pin Configurations and Function Descriptions Block Diagram Typical Performance Characteristics Theory of Operation Main Control Loop Power and Bias Supplies (VIN, EXTVCC, DRVCC, and INTVCC) High-Side Bootstrap Capacitor Dead Time Control (DTCA and DTCB Pins) Start-Up and Shutdown (RUN, OVLO, and TRACK/SS Pins) Light Load Operation: Burst Mode Operation, Pulse-Skipping Mode, or Forced Continuous Mode (MODE Pin) Frequency Selection, Spread Spectrum, and PhaseLocked Loop (FREQ and PLLIN/SPREAD Pins) Input Supply Overvoltage Lockout (OVLO Pin) Output Overvoltage Protection Foldback Current Power Good Applications Information Inductor Value Calculation Inductor Core Selection Current Sense Selection Low Value Resistor Current Sensing Inductor DCR Current Sensing Setting the Operating Frequency Selecting the Light-Load Operating Mode Dead Time Control (DTCA and DTCB Pins) DTCX Pins Tied to INTVCC or Ground (Adaptive Dead Time Control) DTCX Pin Connected with a Resistor to GND Power MOSFET Selection CIN and COUT Selection Setting the Output Voltage RUN Pin and Overvoltage/Undervoltage Lockout Soft-Start and Tracking (TRACK/SS Pin) DRVCC and INTVCC Regulators (OPTI-DRIVE) Topside MOSFET Driver Supply (CB, DB) Minimum On-Time Considerations Fault Conditions: Current Limit and Foldback Fault Conditions: Overvoltage Protection Fault Conditions: Overtemperature Protection Phase-Locked Loop and Frequency Synchronization Efficiency Considerations Checking Transient Response Design Example PC Board Layout Checklist PC Board Layout Debugging Typical Application Related Parts Outline Dimensions Ordering Guide