Datasheet LT3433 (Analog Devices)

LT3433 High Voltage Step-Up/Step-Down DC/DC Converter
U FEATURES DESCRIPTIO
■
Automatic Step-Up and Step-Down Conversion
The LT®3433 is a 200kHz fixed-frequency current mode ■
Uses a Single Inductor
switching regulator that provides both step-up and step- ■
Wide 4V to 60V Input Voltage Range
down regulation using a single inductor. The IC operates ■
VOUT from 3.3V to 20V
over a 4V to 60V input voltage range making it suitable for ■
Dual Internal 500mA Switches
use in various wide input voltage range applications such ■ 100µA No-Load Quiescent Current as automotive electronics that must withstand both load ■ Low Current Shutdown dump and cold crank conditions. ■ ±1% Output Voltage Accuracy Internal control circuitry monitors system conditions and ■ 200kHz Operating Frequency converts from single switch buck operation to dual switch ■ Boosted Supply Pin to Saturate High Side Switch bridged operation when required, seamlessly changing ■ Frequency Foldback Protection between step-down and step-up voltage conversion. ■ Current Limit Foldback Protection ■ Current Limit Unaffected by Duty Cycle Optional Burst Mode® operation reduces no-load quies- ■ 16-lead Thermally Enhanced TSSOP Package cent current to 100µA and maintains high efficiencies with
U
light loads.
APPLICATIO S
Current limit foldback and frequency foldback help pre- ■ 12V Automotive Systems vent inductor current runaway during start-up. Program- ■ Wall Adapter Powered Systems mable soft-start helps prevent output overshoot at start-up. ■ 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
U TYPICAL APPLICATIO 4V to 60V to 5V DC/DC Converter Maximum Output with Burst Mode Operation Current vs VIN Efficiency
1N4148 500 90 V V IN V OUT = 5V IN VBST 2.2µF 0.1µF 80 BUCK SHDN SWH 400 VIN = 13.8V 0.01µF LT3433 70 B160A SS 330pF 100µH B120A 300 60 VC SWL VOUT + VIN = 4V 68k 50 VOUT 47µF 200 1N4148 EFFICIENCY (%) BRIDGED 40 1nF VBIAS 0.1µF 309k 100 30 MAXIMUM OUTPUT CURRENT (mA) BURST_EN VFB SGND PGND 100k 20 0 0 10 20 30 40 50 60 0.1 1 10 100 1000 V OUTPUT CURRENT (mA) 3433 TA01 IN (V) 3433 TA01b 3433 TA01c 3433f 1