Datasheet LT8708 (Analog Devices) - 8
| 制造商 | Analog Devices |
| 描述 | 80V Synchronous 4-Switch Buck-Boost DC/DC Controller with Bidirectional Capability |
| 页数 / 页 | 64 / 8 — ELECTRICAL CHARACTERISTICS. The. denotes the specifications which apply … |
| 修订版 | A |
| 文件格式/大小 | PDF / 3.9 Mb |
| 文件语言 | 英语 |
ELECTRICAL CHARACTERISTICS. The. denotes the specifications which apply over the full operating
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LT8708
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VINCHIP = 12V, SHDN = 3V, DIR = 3V unless otherwise noted (Note 3). PARAMETER CONDITIONS MIN TYP MAX UNITS
CLKOUT Rise Time CLOAD = 200pF 20 ns CLKOUT Fall Time CLOAD = 200pF 20 ns CLKOUT Phase Delay SYNC Rising to CLKOUT Rising, fOSC = 100kHz l 160 180 200 degrees
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 5:
Do not apply a voltage or current source to these pins. They may cause permanent damage to the device. Exposure to any Absolute must be connected to capacitive loads only, otherwise permanent damage Maximum Rating condition for extended periods may affect device may occur. reliability and lifetime.
Note 6:
Negative voltages on the SW1 and SW2 pins are limited, in an
Note 2:
Do not force voltage on the VC pin. application, by the body diodes of the external NMOS devices, M2 and
Note 3:
The LT8708E is guaranteed to meet performance specifications M3, or parallel Schottky diodes when present. The SW1 and SW2 pins from 0°C to 125°C junction temperature. Specifications over the –40°C are tolerant of these negative voltages in excess of one diode drop below to 125°C operating junction temperature range are assured by design, ground, guaranteed by design. characterization and correlation with statistical process controls. The
Note 7:
This IC includes overtemperature protection that is intended LT8708I is guaranteed over the full –40°C to 125°C junction temperature to protect the device during momentary overload conditions. Junction range. The LT8708H is guaranteed over the full –40°C to 150°C operating temperature will exceed the maximum operating junction temperature junction temperature range. when overtemperature protection is active. Continuous operation above
Note 4:
Rise and fall times are measured using 10% and 90% levels. Delay the specified maximum operating junction temperature may impair times are measured using 50% levels. device reliability.
Note 8:
Do not force voltage or current into these pins. Rev 0 8 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Typographical Conventions Start-Up Start-Up: SHDN Pin Start-Up: SWEN Pin Start-Up: Soft-Start of Switching Regulator Control Overview Power Switch Control Switch Control: Buck Region (VIN >> VOUT) Switch Control: Buck-Boost (VIN ≅ VOUT) Switch Control: Boost Region (VIN << VOUT) Switch Control: Soft-Start Uni and Bidirectional Conduction Bidirectional Conduction: CCM Unidirectional Conduction: DCM Unidirectional Conduction: HCM Unidirectional Conduction: Burst Mode Error Amplifiers VOUT Regulation and Sensing VOUT: Regulation VOUT: Above Regulation VOUT: Below Regulation and Undervoltage VIN Regulation and Sensing VIN: Regulation VIN: Above Regulation and Overvoltage VIN: Below Regulation Current Monitoring and Limiting Monitoring and Limiting: IMON Pins Monitoring: ICP and ICN Pins INTVCC/EXTVCC/GATEVCC/LDO33 Power CLKOUT and Temperature Sensing Applications Information Verify the Power Flow Conditions Operating Frequency Selection Internal Oscillator SYNC Pin and Clock Synchronization CLKOUT Pin and Clock Synchronization Inductor Current Sensing and Slope Compensation RSENSE Selection and Maximum Current RSENSE Selection: Max RSENSE in the Boost Region RSENSE Selection: Max RSENSE in the Buck Region RSENSE Selection: Final RSENSE Value RSENSE Filtering Inductor (L) Selection L Selection: Load Current in Buck and Boost Regions L Selection: Subharmonic Oscillations L Selection: Maximum Current Rating Power MOSFET Selection CIN and COUT Selection Schottky Diode (D1, D2, D3, D4) Selection Topside MOSFET Driver Supply (CB1, DB1, CB2, DB2) Top Driver: Boost Cap Charge Control Block Top Driver: Boost Diodes DB1 and DB2 VINHIMON, VOUTLOMON and RVSOFF IIN and IOUT Current Monitoring and Limiting Loop Compensation INTVCC Regulators and EXTVCC Connection LDO33 Regulator Voltage Lockouts Junction Temperature Measurement Thermal Shutdown Efficiency Considerations Circuit Board Layout Checklist Hot Plugging Considerations Design Example Typical Applications Package Description Typical Application Related Parts
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VINCHIP = 12V, SHDN = 3V, DIR = 3V unless otherwise noted (Note 3). PARAMETER CONDITIONS MIN TYP MAX UNITS
CLKOUT Rise Time CLOAD = 200pF 20 ns CLKOUT Fall Time CLOAD = 200pF 20 ns CLKOUT Phase Delay SYNC Rising to CLKOUT Rising, fOSC = 100kHz l 160 180 200 degrees
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 5:
Do not apply a voltage or current source to these pins. They may cause permanent damage to the device. Exposure to any Absolute must be connected to capacitive loads only, otherwise permanent damage Maximum Rating condition for extended periods may affect device may occur. reliability and lifetime.
Note 6:
Negative voltages on the SW1 and SW2 pins are limited, in an
Note 2:
Do not force voltage on the VC pin. application, by the body diodes of the external NMOS devices, M2 and
Note 3:
The LT8708E is guaranteed to meet performance specifications M3, or parallel Schottky diodes when present. The SW1 and SW2 pins from 0°C to 125°C junction temperature. Specifications over the –40°C are tolerant of these negative voltages in excess of one diode drop below to 125°C operating junction temperature range are assured by design, ground, guaranteed by design. characterization and correlation with statistical process controls. The
Note 7:
This IC includes overtemperature protection that is intended LT8708I is guaranteed over the full –40°C to 125°C junction temperature to protect the device during momentary overload conditions. Junction range. The LT8708H is guaranteed over the full –40°C to 150°C operating temperature will exceed the maximum operating junction temperature junction temperature range. when overtemperature protection is active. Continuous operation above
Note 4:
Rise and fall times are measured using 10% and 90% levels. Delay the specified maximum operating junction temperature may impair times are measured using 50% levels. device reliability.
Note 8:
Do not force voltage or current into these pins. Rev 0 8 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Typographical Conventions Start-Up Start-Up: SHDN Pin Start-Up: SWEN Pin Start-Up: Soft-Start of Switching Regulator Control Overview Power Switch Control Switch Control: Buck Region (VIN >> VOUT) Switch Control: Buck-Boost (VIN ≅ VOUT) Switch Control: Boost Region (VIN << VOUT) Switch Control: Soft-Start Uni and Bidirectional Conduction Bidirectional Conduction: CCM Unidirectional Conduction: DCM Unidirectional Conduction: HCM Unidirectional Conduction: Burst Mode Error Amplifiers VOUT Regulation and Sensing VOUT: Regulation VOUT: Above Regulation VOUT: Below Regulation and Undervoltage VIN Regulation and Sensing VIN: Regulation VIN: Above Regulation and Overvoltage VIN: Below Regulation Current Monitoring and Limiting Monitoring and Limiting: IMON Pins Monitoring: ICP and ICN Pins INTVCC/EXTVCC/GATEVCC/LDO33 Power CLKOUT and Temperature Sensing Applications Information Verify the Power Flow Conditions Operating Frequency Selection Internal Oscillator SYNC Pin and Clock Synchronization CLKOUT Pin and Clock Synchronization Inductor Current Sensing and Slope Compensation RSENSE Selection and Maximum Current RSENSE Selection: Max RSENSE in the Boost Region RSENSE Selection: Max RSENSE in the Buck Region RSENSE Selection: Final RSENSE Value RSENSE Filtering Inductor (L) Selection L Selection: Load Current in Buck and Boost Regions L Selection: Subharmonic Oscillations L Selection: Maximum Current Rating Power MOSFET Selection CIN and COUT Selection Schottky Diode (D1, D2, D3, D4) Selection Topside MOSFET Driver Supply (CB1, DB1, CB2, DB2) Top Driver: Boost Cap Charge Control Block Top Driver: Boost Diodes DB1 and DB2 VINHIMON, VOUTLOMON and RVSOFF IIN and IOUT Current Monitoring and Limiting Loop Compensation INTVCC Regulators and EXTVCC Connection LDO33 Regulator Voltage Lockouts Junction Temperature Measurement Thermal Shutdown Efficiency Considerations Circuit Board Layout Checklist Hot Plugging Considerations Design Example Typical Applications Package Description Typical Application Related Parts