Datasheet LTC7897 (Analog Devices)
| 制造商 | Analog Devices |
| 描述 | 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 |
| 页数 / 页 | 53 / 1 — Data Sheet. LTC7897. FEATURES. GENERAL DESCRIPTION. APPLICATIONS. TYPICAL … |
| 文件格式/大小 | PDF / 1.6 Mb |
| 文件语言 | 英语 |
Data Sheet. LTC7897. FEATURES. GENERAL DESCRIPTION. APPLICATIONS. TYPICAL APPLICATION. VIN. 16V TO 100V. 135V MAX. 47µF. RUN. 100. 2.2µF. TGUP
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Data Sheet LTC7897
140V, Low IQ, Synchronous Buck Controller with Programmable 5V to 10V Gate Drive
FEATURES GENERAL DESCRIPTION
Wide V The LTC®7897 is a high performance, 100% duty cycle IN Range: 4V to 135V (140V ABS MAX) Wide Output Voltage Range: 0.8V ≤ V capable, synchronous step-down, DC/DC switching OUT ≤ 135V (140V ABS MAX) regulator controller that drives all N-channel Adjustable Gate Drive Level: 5V to 10V (OPTI-DRIVE, synchronous silicon metal oxide field effect transistor 14V ABS MAX) (MOSFET) power stages. Synchronous rectification increases efficiency, reduces power loss, and simplifies Adjustable Driver Voltage UVLO the application design by reducing thermal Adaptive or Resistor Adjustable Dead Times requirements. Split-Output Gate Drivers for Adjustable Turn-On and Turn-Off Driver Strengths The wide input and output voltage ranges of the 100% Duty Cycle Operation LTC7897 enable not only high step-down ratios but also Low Operating I a wide range of positive to negative voltage conversion. Q: 5μA (48VIN to 3.3VOUT) Spread Spectrum Frequency Modulation The gate drivers of the LTC7897 provide robustness with Programmable Frequency (100kHz to 2.5MHz) a 14V ABS MAX rating and flexibility with adjustable Synchronizable Frequency (100kHz to 2.5MHz) drive levels and dead times to optimize applications. 28-Pin (4mm x 5mm) QFN Package The gate drive voltage of the LTC7897 can optionally be adjusted from 5V to 10V to allow use of logic-level or
APPLICATIONS
standard threshold MOSFETs. The dead times of the LTC7897 can be optimized with external resistors for Industrial Power Systems margin or to tailor the application for higher efficiency Military/Avionics and allow for high frequency operation. Telecommunications Power Systems
TYPICAL APPLICATION VIN 16V TO 100V 135V MAX 47µF ×2 RUN VIN 100 2.2µF TGUP ×4 TGDN DRVCC LTC7897 BOOST 95 0.1µF 5.5µH 2mΩ ITH V SW OUT TRACK/SS 12V, 20A ) FREQ (% 100µF PLLIN BGUP Y ×3 C 187kΩ ILIM BGDN 90 VPRG ENI 22µF PGOOD CI ×4 F DTCB + EF Burst Mode 0.1µF SENSE DTCA V OVLO OUT = 12V SENSE − MODE 85 EXTV V CC DRVUV IN = 24V 140kΩ DRVSET V VIN = 48V FB INTV DRV GND V CC CC IN = 100V V 0.1µF 4.7µF 10kΩ IN = 135V 800.01 0.1 1 10 20
001
LOAD CURRENT (A)
002
Figure 1. High Efficiency 100V/12V Output Step-Down Converter Figure 2. VOUT Efficiency for Figure 1
Rev. A DOCUMENT FEEDBACK
TECHNICAL SUPPORT
One Analog Wa y, Wilmington, MA 01887 -2356, U.S.A. Tel: 781.329.47 00 ©2025 A n a l o g D e v i c e s , I n c . A l l r i g h t s r e s e r v e d . 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
140V, Low IQ, Synchronous Buck Controller with Programmable 5V to 10V Gate Drive
FEATURES GENERAL DESCRIPTION
Wide V The LTC®7897 is a high performance, 100% duty cycle IN Range: 4V to 135V (140V ABS MAX) Wide Output Voltage Range: 0.8V ≤ V capable, synchronous step-down, DC/DC switching OUT ≤ 135V (140V ABS MAX) regulator controller that drives all N-channel Adjustable Gate Drive Level: 5V to 10V (OPTI-DRIVE, synchronous silicon metal oxide field effect transistor 14V ABS MAX) (MOSFET) power stages. Synchronous rectification increases efficiency, reduces power loss, and simplifies Adjustable Driver Voltage UVLO the application design by reducing thermal Adaptive or Resistor Adjustable Dead Times requirements. Split-Output Gate Drivers for Adjustable Turn-On and Turn-Off Driver Strengths The wide input and output voltage ranges of the 100% Duty Cycle Operation LTC7897 enable not only high step-down ratios but also Low Operating I a wide range of positive to negative voltage conversion. Q: 5μA (48VIN to 3.3VOUT) Spread Spectrum Frequency Modulation The gate drivers of the LTC7897 provide robustness with Programmable Frequency (100kHz to 2.5MHz) a 14V ABS MAX rating and flexibility with adjustable Synchronizable Frequency (100kHz to 2.5MHz) drive levels and dead times to optimize applications. 28-Pin (4mm x 5mm) QFN Package The gate drive voltage of the LTC7897 can optionally be adjusted from 5V to 10V to allow use of logic-level or
APPLICATIONS
standard threshold MOSFETs. The dead times of the LTC7897 can be optimized with external resistors for Industrial Power Systems margin or to tailor the application for higher efficiency Military/Avionics and allow for high frequency operation. Telecommunications Power Systems
TYPICAL APPLICATION VIN 16V TO 100V 135V MAX 47µF ×2 RUN VIN 100 2.2µF TGUP ×4 TGDN DRVCC LTC7897 BOOST 95 0.1µF 5.5µH 2mΩ ITH V SW OUT TRACK/SS 12V, 20A ) FREQ (% 100µF PLLIN BGUP Y ×3 C 187kΩ ILIM BGDN 90 VPRG ENI 22µF PGOOD CI ×4 F DTCB + EF Burst Mode 0.1µF SENSE DTCA V OVLO OUT = 12V SENSE − MODE 85 EXTV V CC DRVUV IN = 24V 140kΩ DRVSET V VIN = 48V FB INTV DRV GND V CC CC IN = 100V V 0.1µF 4.7µF 10kΩ IN = 135V 800.01 0.1 1 10 20
001
LOAD CURRENT (A)
002
Figure 1. High Efficiency 100V/12V Output Step-Down Converter Figure 2. VOUT Efficiency for Figure 1
Rev. A DOCUMENT FEEDBACK
TECHNICAL SUPPORT
One Analog Wa y, Wilmington, MA 01887 -2356, U.S.A. Tel: 781.329.47 00 ©2025 A n a l o g D e v i c e s , I n c . A l l r i g h t s r e s e r v e d . 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