LT3433IFE#PBF Analog Devices

LT3433 High Voltage Step-Up/Step-Down DC/DC Converter FEATURES DESCRIPTIO n Automatic Step-Up and Step-Down Conversion The LT 3433 is a 200kHz fixed-frequency current mode n Uses a Single Inductor switching regulator that provides both step-up and step- n Wide 4V to 60V Input Voltage Range down regulation using a single inductor. The IC operates n V from 3.3V to 20V over a 4V to 60V input voltage range making it suitable for OUT n Dual Internal 500mA Switches use in various wide input voltage range applications such n 100m A No-Load Quiescent Current as automotive electronics that must withstand both load n Low Current Shutdown dump and cold crank conditions. n 1% Output Voltage Accuracy Internal control circuitry monitors system conditions and n 200kHz Operating Frequency converts from single switch buck operation to dual switch n Boosted Supply Pin to Saturate High Side Switch bridged operation when required, seamlessly changing n Frequency Foldback Protection between step-down and step-up voltage conversion. n Current Limit Foldback Protection n Optional Burst Mode operation reduces no-load quies- Current Limit Unaffected by Duty Cycle n cent current to 100m A and maintains high efficiencies with 16-lead Thermally Enhanced TSSOP Package light loads. U APPLICATIO S Current limit foldback and frequency foldback help pre- n vent inductor current runaway during start-up. Program- 12V Automotive Systems n mable soft-start helps prevent output overshoot at start-up. Wall Adapter Powered Systems n Battery Power Voltage Buffering The LT3433 is available in a 16-lead thermally enhanced , LTC and LT are registered trademarks of Linear Technology Corporation. TSSOP package. Burst Mode is a registered trademark of Linear Technology Corporation. U.S. patent number: 5731694 TYPICAL APPLICATIO Maximum Output 4V to 60V to 5V DC/DC Converter Current vs V with Burst Mode Operation Efficiency IN 1N4148 90 500 V = 5V OUT V V V IN IN BST 80 2.2F 0.1F BUCK V = 13.8V 400 SHDN SWH IN 0.01F 70 LT3433 B160A SS 100H 330pF 300 60 B120A V C SWL V OUT V = 4V IN + 50 68k V OUT 200 47F 1N4148 BRIDGED 40 V BIAS 1nF 0.1F 309k 100 30 BURST EN V FB 20 0 SGND PGND 100k 0 10 20 30 40 50 60 0.1 1 10 100 1000 OUTPUT CURRENT (mA) V (V) 3433 TA01 IN 3433 TA01b 3433 TA01c 3433f 1 MAXIMUM OUTPUT CURRENT (mA) EFFICIENCY (%) U ULT3433 ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) TOP VIEW Input Supply (V ) .................................... 0.3V to 60V IN ORDER PART Boosted Supply (V ) .............. 0.3V to V + 30V SGND 1 16 SGND BST SW H NUMBER (V = 80V) V 2 15 SW L BST(MAX) BST LT3433EFE SW H 3 14 PWRGND Internal Supply (V ) ............................. 0.3V to 30V BIAS LT3433IFE V 4 13 V SW H Switch Voltage .................................. 2V to 60V IN OUT 17 BURST EN 5 12 V BIAS SW L Switch Voltage ............................... 0.3V to 30V V 6 11 SHDN C Feedback Voltage (V ) ............................... 0.3V to 5V FB V 7 10 SS FB Burst Enable Pin (V ) ................... 0.3V to 30V BURST EN FE PART MARKING SGND 8 9 SGND Shutdown Pin (V ) ............................. 0.3V to 60V SHDN FE PACKAGE 3433EFE Operating Junction Temperature Range (Note 5) 16-LEAD PLASTIC TSSOP 3433IFE LT3433E (Note 6) ............................ 40 C to 125 C T = 125 C, q = 40 C/W, q = 10 C/W JMAX JA JC EXPOSED PAD (PIN 17) LT3433I ........................................... 40 C to 125 C MUST BE SOLDERED TO SGND Storage Temperature Range ................ 65 C to 150 C Lead Temperature (Soldering, 10 sec)................. 300 C Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The l denotes specifications that apply over the full operating temperature range, otherwise specifications are at T = 25 C. A V = 13.8V, V = 1.25V, V = 5V, V = 0V, V V = 5V, unless otherwise noted. IN FB OUT BURST EN BST IN SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Operating Voltage Range l460 V IN V Undervoltage Lockout Enable Threshold l 3.4 3.95 V IN(UVLO) Undervoltage Lockout Hysteresis 160 mV V Operating Voltage Range l 3.3 20 V OUT V Operating Voltage Range V < V + 20V l 75 V BST BST SW H V V l 3.3 20 V BST SW H I Normal Operation (Notes 2, 3) l 580 940 m A VIN Burst Mode Operation V < 0.6V l 100 190 m A VC < 0.4V l 10 25 m A Shutdown V SHDN V Internal Supply Output Voltage l 2.6 2.9 V BIAS Operating Voltage Range l 20 V I Normal Operation l 660 990 m A VBIAS Burst Mode Operation V < 0.6V 0.1 m A VC < 0.4V 0.1 m A Shutdown V SHDN Short-Circuit Current Limit 4.5 mA R Boost Supply Switch On-Resistance I = 500mA l 0.8 1.2 W SWH(ON) SW R Output Supply Switch On-Resistance I = 500mA l 0.6 1 W SWL(ON) SW V Shutdown Pin Thresholds Disable l 0.4 V SHDN Enable l 1V I /I Boost Supply Switch Drive Current High Side Switch On, I = 500mA l 30 50 mA/A VBST SW SW I /I Output Supply Switch Drive Current Low Side Switch On, I = 500mA l 30 50 mA/A VOUT SW SW I Switch Current Limit l 0.5 0.7 0.9 A LIM Foldback Current Limit V = 0V 0.35 A FB I Soft-Start Output Current l 359 m A SS 3433f 2 U W U U WWW