LT3640 absoluTe MaxiMuM raTings (Note 1) VIN, EN/UVLO Voltage (Note 7) ...55V SW2 Voltage .. –0.3V to (VIN2 + 0.3V) WDE Voltage ...30V Operating Junction Temperature Range (Note 2) BST Above SW, SW1 Voltage ... –0.3V to 6V LT3640E ... –40°C to 125°C SW1 Above SW Voltage ... –0.3V to 6V LT3640I .. –40°C to 125°C VIN2, SYNC, EN2, PGOOD, WDI, Storage Temperature Range ... –65°C to 150°C WDO, RST1, RST2, Voltages ... –0.3V to 6V Lead Temperature, FE Only (Soldering, 10 sec) .. 300°C SS1, SS2, FB1, FB2, RT, CWDT, CPOR Voltages………... ... –0.3V to 2.5V pin conFiguraTion TOP VIEW TOP VIEW FB2 1 28 SS2 PGOOD 2 27 EN2 EN/UVLO 3 26 GND EN/UVLO PGOOD FB2 SS2 EN2 GND 28 27 26 25 24 23 SYNC 4 25 SW2 SYNC 1 22 SW2 SS1 5 24 VIN2 SS1 2 21 VIN2 FB1 6 23 GND FB1 3 20 GND RT 7 22 V 29 IN RT 4 19 29 VIN RST2 8 GND 21 BST RST2 5 GND 18 BST RST1 9 20 SW RST1 6 17 SW WDO 10 19 SW1 WDO 7 16 SW1 CWDT 11 18 DA CWDT 8 15 DA CPOR 12 17 NC 9 10 11 12 13 14 WDE 13 16 GND NC CPOR WDE WDI GND GND WDI 14 15 GND UFD PACKAGE FE PACKAGE 28-LEAD (4mm s 5mm) PLASTIC QFN 28-LEAD PLASTIC TSSOP θJA = 34°C/W, θJC = 2.7°C/W θ EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB JA = 30°C/W, θJC = 8°C/W EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB orDer inForMaTion LEAD FREE FINISHTAPE AND REELPART MARKING*PACKAGE DESCRIPTIONTEMPERATURE RANGE LT3640EFE#PBF LT3640EFE#TRPBF LT3640FE 28-Lead Plastic TSSOP –40°C to 125°C LT3640IFE#PBF LT3640IFE#TRPBF LT3640FE 28-Lead Plastic TSSOP –40°C to 125°C LT3640EUFD#PBF LT3640EUFD#TRPBF 3640 28-Lead (4mm × 5mm) Plastic QFN –40°C to 125°C LT3640IUFD#PBF LT3640IUFD#TRPBF 3640 28-Lead (4mm × 5mm) Plastic QFN –40°C to 125°C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ 3640f Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Timing Diagrams Operation Applications Information Typical Applications Package Description Typical Application Related Parts