LTC3421 ABSOLUTE MAXIMUM RATINGSPACKAGE/ORDER INFORMATION(Note 1) VIN, VOUT, VOUTS Voltage ... –0.3V to 6V TOP VIEW BURST, SHDN, SS, ENB, SW, V C LBI LBO V IN V OUT V OUT LBO, LBI, SYNC Voltages ... –0.3V to 6V 24 23 22 21 20 19 Operating Temperature Range FB 1 18 VOUTS (Notes 2, 5) ..–40°C to 85°C SHDN 2 17 VOUT Storage Temperature Range .. –65°C to 125°C VREF 3 25 16 SW Lead Temperature (Soldering, 10 sec) ...300°C ENB 4 GND 15 SW RT 5 14 SW SS 6 13 PGND 7 8 9 10 11 12 I LIM SYNC GND BURST PGND PGND UF PACKAGE 24-LEAD (4mm × 4mm) PLASTIC QFN TJMAX = 125°C, θJA = 40°C/W 1 LAYER BOARD θJA = 35°C/W 4 LAYER BOARD, θJC = 2.6°C/W EXPOSED PAD IS GND (PIN 25) MUST BE SOLDERED TO PCB ORDER INFORMATIONLEAD FREE FINISHTAPE AND REELPART MARKINGPACKAGE DESCRIPTIONTEMPERATURE RANGE LTC3421EUF#PBF LTC3421EUF#TRPBF 3421 24-Lead Plastic QFN –40°C to 85°C Contact the factory for parts specified with wider operating temperature ranges. Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix. ELECTRICAL CHARACTERISTICSThe l denotes the specifications which apply over the full operatingjunction temperature range, otherwise specifications are at TA = 25°C. VIN = 1.2V, VOUT = 3.3V, RT = 28k, unless otherwise noted. PARAMETERCONDITIONSMINTYPMAXUNITS Minimum VIN Start-Up Voltage ILOAD < 1mA 0.88 1 V Minimum VIN Operating Voltage (Note 4) l 0.5 V Output Voltage Adjust Range 2.25 5.25 V l 2.40 5.25 V Feedback Voltage l 1.196 1.220 1.244 V Feedback Input Current VFB = 1.22V 1 50 nA Quiescent Current—Burst Mode Operation VC = 0V, ENB = 0V (Note 3) 12 20 µA VC = 0V, ENB = 2V (Note 3) 23 50 µA Rev. A For more information www.analog.com 3 Document Outline Description Typical Application Absolute Maximum Ratings Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Package Description Typical Application Related Parts Features Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics Package/Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Low Voltage Start-Up Low Noise Fixed Frequency Operation Burst Mode Operation Output Disconnect and Inrush Limiting Applications Information Component Selection Typical Application Package Description Revision History Typical Application Related Parts