Datasheet LT8708 (Analog Devices) - 10

LT8708
TYPICAL PERFORMANCE CHARACTERISTICS Minimum Inductor Current Sense INTVCC Line Regulation Minimum Inductor Current Sense Voltage vs Duty Cycle (EXTVCC = 0V) Voltage at Minimum Duty Cycle
0 7.0 0 –20 6.5 –20 –40 6.0 –40 BUCK REGION –60 (V) 5.5 V CC –60 –80 INT BUCK REGION –|CSP–CSN| (mV) 5.0 –|CSP–CSN| (mV) –80 –100 –120 4.5 –100 BOOST REGION BOOST REGION –140 4.0 –120 0 20 40 60 80 100 4 6 8 10 12 14 16 18 20 –45 –20 5 30 55 80 105 130 155 M2 OR M3 DUTY CYCLE (%) VIN (V) TEMPERATURE (°C) 8708 G10 8708 G11 8708 G12
INTVCC Line Regulation Maximum and Minimum VC Maximum and Minimum V vs SS (V C vs SS IN = 12V) IMONx, ICx Output Current
2.5 7.0 250.0 TJ = 25°C 225.0 IMON_INN BOOST REGION IMON_ON 2.0 200.0 ICN MAXIMUM V EXTV C CC RISING 175.0 BUCK REGION 6.5 150.0 IMON_INP 1.5 (V) 125.0 IMON_OP (V) V CC ICP V C 100.0 1.0 INT 6.0 75.0 MINIMUM VC EXTV 50.0 CC FALLING 0.5 IMONX, ICX CURRENT (µA) 25.0 0 0 5.5 –25.0 0 0.3 0.6 0.9 1.2 1.5 4 6 8 10 12 –200 –100 0 100 200 SS (V) EXTVCC (V) CSPIN–CSNIN (mV) 8708 G13 8708 G14 CSPOUT–CSNOUT (mV) 8708 G15
LDO33 Pin Regulation VIN Supply Current vs Voltage CLKOUT Duty Cycle (ILDO33 = 1mA) (Not Switching)
100 3.5 3.5 3.0 80 3.0 2.5 60 2.0 2.5 (mA) Y CYCLE (%) 40 LDO33 (V) I IN 1.5 DUT 1.0 2.0 150°C 150°C 20 –45°C –45°C 25°C 0.5 25°C 0 1.5 0 –45 –20 5 30 55 80 105 130 155 2.5 3 3.5 4 4.5 5 5.5 6 6.5 5 20 35 50 65 80 TEMPERATURE (°C) INTVCC (V) VIN (V) 8708 G16 8708 G17 8708 G18 Rev 0 10 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