Datasheet LT8708-1 (Analog Devices) - 8
| Manufacturer | Analog Devices |
| Description | 80V Synchronous 4-Switch Buck-Boost DC/DC Slave Controller for LT8708 Multiphase System |
| Pages / Page | 36 / 8 — TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. … |
| Revision | A |
| File Format / Size | PDF / 2.0 Mb |
| Document Language | English |
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. Efficiency vs Output Current
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LT8708-1
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. Efficiency vs Output Current Efficiency vs Output Current Efficiency vs Output Current (Boost Region – Page 32) (Buck Region – Page 32) (Buck-Boost Region – Page 32)
100 100 100 90 90 90 80 80 80 70 70 70 60 60 60 50 50 50 40 40 40 EFFICIENCY (%) EFFICIENCY (%) EFFICIENCY (%) 30 VIN = 11.5V 30 VIN = 16V 30 VIN = 14.5V VOUT = 14.5V VOUT = 12V V 20 OUT = 14.5V HCM 20 HCM 20 HCM 10 DCM 10 DCM DCM 10 CCM CCM CCM 0 0 0 0.01 0.1 1 10 30 0.01 0.1 1 10 30 0.01 0.1 1 10 30 IOUT (A) IOUT (A) IOUT (A) 87081 G01 87081 G02 87081 G03
CSPOUT – CSNOUT Voltages CSNOUT – CSPOUT Voltages (ICP = 1.218V, ICN = 0V) (ICP = 1.218V, ICN = 0V) (Five Parts) (Five Parts) IMON_OP Output Current
80 80 230 VC ≅ 1.3V VC = ~1.3V ICP = ICN = 0.348V 70 70 190 60 60 150 TAGES (mV) TAGES (mV) 50 50 110 40 40 70 IMON_OP CURRENT (µA) 30 CSPOUT–CSNOUT VOL 30 30 CSNOUT–CSPOUT VOL 20 20 –10 –50 –30 –10 10 30 50 70 90 110 130 150 –50 –30 –10 10 30 50 70 90 110 130 150 –150 –75 0 75 150 TEMPERATURE (°C) TEMPERATURE (°C) CSPOUT–CSNOUT (mV) 87081 G04 87081 G05 87081 G06
Maximum and Minimum VC vs Maximum and Minimum VC vs SS Maximum and Minimum VC vs SS ICP_ICN (SS = 0) (ICP = ICN =0.348V) (ICP or ICN = 1V)
2.5 2.5 2.5 TJ = 25°C T TJ = 25°C MAXIMUM V J = 25°C C MAXIMUM VC MAXIMUM VC 2.0 2.0 2.0 1.5 1.5 1.5 (V) (V) (V) V C V C V C 1.0 1.0 1.0 0.5 0.5 0.5 MINIMUM VC MINIMUM VC MINIMUM VC 0 0 0 0 0.25 0.50 0.75 1 1.25 0 0.5 1 1.5 2 0 0.25 0.50 0.75 1 ICP/ICN VOLTAGE (V) SS (V) SS (V) 87081 G07 87081 G08 87081 G09 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 Pin Functions Block Diagram Operation Applications Information Package Description Typical Application Related Parts Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Common LT8708-1 and LT8708 Features Adding Phases to an LT8708 Application Adding Phases: The Master LT8708 Adding Phases: The Slave LT8708-1 Start-Up Start-Up: SWEN Pin Start-Up: Soft-Start of Switching Regulator Control Overview Power Switch Control Unidirectional and Bidirectional Conduction Error Amplifiers Transfer Function: IOUT(SLAVE) Vs IOUT(MASTER) Transfer Function: CCM Transfer Function: DCM, HCM and Burst Mode Operation Current Monitoring and Limiting Monitoring: IOUT(SLAVE) Monitoring and Limiting: IIN(SLAVE) Multiphase Clocking Applications Information Quick-Start Multiphase Setup Quick Setup: Design the Master Phase Quick Setup: Design the Slave Phase(s) Quick Setup: Evaluation Choosing the Total Number of Phases Operating Frequency Selection CIN and COUT Selection CIN and COUT Selection: VIN Capacitance CIN and COUT Selection: VOUT Capacitance VINHIMON, VOUTLOMON and RVSOFF Configuring the IIN(SLAVE) Current Limits Regulating IOUT(SLAVE) IOUT(SLAVE): Circuit Description IOUT(SLAVE): Configuration Loop Compensation Voltage Lockouts Circuit Board Layout Checklist Design Example Typical Applications Package Description Typical Application Related Parts
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. Efficiency vs Output Current Efficiency vs Output Current Efficiency vs Output Current (Boost Region – Page 32) (Buck Region – Page 32) (Buck-Boost Region – Page 32)
100 100 100 90 90 90 80 80 80 70 70 70 60 60 60 50 50 50 40 40 40 EFFICIENCY (%) EFFICIENCY (%) EFFICIENCY (%) 30 VIN = 11.5V 30 VIN = 16V 30 VIN = 14.5V VOUT = 14.5V VOUT = 12V V 20 OUT = 14.5V HCM 20 HCM 20 HCM 10 DCM 10 DCM DCM 10 CCM CCM CCM 0 0 0 0.01 0.1 1 10 30 0.01 0.1 1 10 30 0.01 0.1 1 10 30 IOUT (A) IOUT (A) IOUT (A) 87081 G01 87081 G02 87081 G03
CSPOUT – CSNOUT Voltages CSNOUT – CSPOUT Voltages (ICP = 1.218V, ICN = 0V) (ICP = 1.218V, ICN = 0V) (Five Parts) (Five Parts) IMON_OP Output Current
80 80 230 VC ≅ 1.3V VC = ~1.3V ICP = ICN = 0.348V 70 70 190 60 60 150 TAGES (mV) TAGES (mV) 50 50 110 40 40 70 IMON_OP CURRENT (µA) 30 CSPOUT–CSNOUT VOL 30 30 CSNOUT–CSPOUT VOL 20 20 –10 –50 –30 –10 10 30 50 70 90 110 130 150 –50 –30 –10 10 30 50 70 90 110 130 150 –150 –75 0 75 150 TEMPERATURE (°C) TEMPERATURE (°C) CSPOUT–CSNOUT (mV) 87081 G04 87081 G05 87081 G06
Maximum and Minimum VC vs Maximum and Minimum VC vs SS Maximum and Minimum VC vs SS ICP_ICN (SS = 0) (ICP = ICN =0.348V) (ICP or ICN = 1V)
2.5 2.5 2.5 TJ = 25°C T TJ = 25°C MAXIMUM V J = 25°C C MAXIMUM VC MAXIMUM VC 2.0 2.0 2.0 1.5 1.5 1.5 (V) (V) (V) V C V C V C 1.0 1.0 1.0 0.5 0.5 0.5 MINIMUM VC MINIMUM VC MINIMUM VC 0 0 0 0 0.25 0.50 0.75 1 1.25 0 0.5 1 1.5 2 0 0.25 0.50 0.75 1 ICP/ICN VOLTAGE (V) SS (V) SS (V) 87081 G07 87081 G08 87081 G09 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 Pin Functions Block Diagram Operation Applications Information Package Description Typical Application Related Parts Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Common LT8708-1 and LT8708 Features Adding Phases to an LT8708 Application Adding Phases: The Master LT8708 Adding Phases: The Slave LT8708-1 Start-Up Start-Up: SWEN Pin Start-Up: Soft-Start of Switching Regulator Control Overview Power Switch Control Unidirectional and Bidirectional Conduction Error Amplifiers Transfer Function: IOUT(SLAVE) Vs IOUT(MASTER) Transfer Function: CCM Transfer Function: DCM, HCM and Burst Mode Operation Current Monitoring and Limiting Monitoring: IOUT(SLAVE) Monitoring and Limiting: IIN(SLAVE) Multiphase Clocking Applications Information Quick-Start Multiphase Setup Quick Setup: Design the Master Phase Quick Setup: Design the Slave Phase(s) Quick Setup: Evaluation Choosing the Total Number of Phases Operating Frequency Selection CIN and COUT Selection CIN and COUT Selection: VIN Capacitance CIN and COUT Selection: VOUT Capacitance VINHIMON, VOUTLOMON and RVSOFF Configuring the IIN(SLAVE) Current Limits Regulating IOUT(SLAVE) IOUT(SLAVE): Circuit Description IOUT(SLAVE): Configuration Loop Compensation Voltage Lockouts Circuit Board Layout Checklist Design Example Typical Applications Package Description Typical Application Related Parts
