Datasheet LT8708 (Analog Devices) - 3

LT8708
ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1)
VCSP – VCSN, VCSPIN – VCSNIN, TOP VIEW VCSPOUT – VCSNOUT ... –0.3V to 0.3V CSP, CSN Voltage ... –0.3V to 3V V CC V LDO33 IMON_ON IMON_OP MODE SWEN INT V INCHIP C Voltage (Note 2) .. –0.3V to 2.2V 40 39 38 37 36 35 34 RT, FBOUT, SS Voltage .. –0.3V to 5V CLKOUT 1 33 CSPIN IMON_INP, IMON_INN, IMON_OP, IMON_ON, SS 2 32 CSNIN ICP, ICN Voltage ... –0.3V to 5V SHDN 3 31 CSNOUT SYNC Voltage .. –0.3V to 5.5V CSN 4 30 CSPOUT INTV CSP 5 CC, GATEVCC Voltage .. –0.3V to 7V ICN 6 29 EXTV V CC BOOST1 – VSW1, VBOOST2 – VSW2 .. –0.3V to 7V DIR 7 41 SWEN, RVSOFF Voltage ... –0.3V to 7V GND 28 ICP FBIN 8 SWEN Current ...0.5mA 27 VINHIMON FBOUT 9 VOUTLOMON RVSOFF Current ...1mA 26 VC 10 25 RVSOFF FBIN, SHDN Voltage .. –0.3V to 30V IMON_INP 11 VINHIMON Voltage ... –0.3V to 30V IMON_INN 12 24 BOOST1 VOUTLOMON Voltage .. –0.3V to 5V RT 13 23 TG1 SYNC 14 22 SW1 DIR, MODE Voltage .. –0.3V to 5V 15 16 17 18 19 20 21 CSNIN, CSPIN, CSPOUT, CSNOUT Voltage –0.3V to 80V CC V GND BG1 BG2 TG2 SW2 INCHIP, EXTVCC Voltage .. –0.3V to 80V TEV BOOST2 SW1, SW2 Voltage ...81V (Note 6) GA BOOST1, BOOST2 Voltage ... –0.3V to 87V UHG PACKAGE 40-LEAD (5mm × 8mm) PLASTIC QFN BG1, BG2, TG1, TG2 .. (Note 5) TJMAX = 150°C, θJA = 36°C/W, θJC = 3.8°C/W EXPOSED PAD (PIN 41) IS GND, MUST BE SOLDERED TO PCB LDO33, CLKOUT ... (Note 8) Operating Junction Temperature Range LT8708E (Notes 3, 8) .. –40°C to 125°C LT8708I (Notes 3, 8) ... –40°C to 125°C LT8708H (Notes 3, 8) ... –40°C to 150°C Storage Temperature Range .. –65°C to 150°C
ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LT8708EUHG#PBF LT8708EUHG#TRPBF 8708 40-Lead (5mm × 8mm) Plastic QFN –40°C to 125°C LT8708IUHG#PBF LT8708IUHG#TRPBF 8708 40-Lead (5mm × 8mm) Plastic QFN –40°C to 125°C LT8708HUHG#PBF LT8708HUHG#TRPBF 8708 40-Lead (5mm × 8mm) Plastic QFN –40°C to 150°C Consult ADI Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix. Rev 0 For more information www.analog.com 3 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