Product Summary

The ltc3728eg/tr is a dual high performance step-down switching regulator controller that drives all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture of the ltc3728eg/tr oallows phase-lockable frequency of up to 550kHz. Power loss and noise due to the ESR of the input capacitors are minimized by operating the two controller output stages out of phase. Applications are (1)Notebook and Palmtop Computers; (2)Telecom Systems; (3)Portable Instruments; (4)Battery-Operated Digital Devices; (5)DC Power Distribution Systems.

Parametrics

ltc3728eg/tr absolute maximum ratings: (1)Input Supply Voltage (VIN): 36V to –0.3V; (2)Top Side Driver Voltages (BOOST1, BOOST2): 42V to –0.3V; (3)Switch Voltage (SW1, SW2): 36V to –5V; (4)INTVCC, EXTVCC, RUN/SS1, RUN/SS2, (BOOST1-SW1), (BOOST2-SW2), PGOOD : 7V to –0.3V; (5)SENSE1+, SENSE2 +, SENSE1–, SENSE2– Voltages : (1.1)INTVCC to –0.3V; (6)PLLIN, PLLFLTR, FCB, Voltage : INTVCC to –0.3V; (7)ITH1, ITH2, VOSENSE1, VOSENSE2 Voltages : 2.7V to –0.3V; (8)Peak Output Current <10μs (TG1, TG2, BG1, BG2): 3A; (9)INTVCC Peak Output Current : 50mA; (10)Operating Temperature Range (Note 7): –40°C to 85°C; (11)Junction Temperature (Note 2): 125°C; (12)Storage Temperature Range : –65°C to 125°C; (13)Lead Temperature (Soldering, 10 sec)(G Package Only): 300°C.

Features

ltc3728eg/tr features: (1)±1% Output Voltage Accuracy; (2)Power Good Output Voltage Indicator; (3)Phase-Lockable Fixed Frequency 250kHz to 550kHz; (4)Dual N-Channel MOSFET Synchronous Drive; (5)Wide VIN Range: 3.5V to 36V Operation; (6)Very Low Dropout Operation: 99% Duty Cycle; (7)Adjustable Soft-Start Current Ramping; (8)Foldback Output Current Limiting; (9)Latched Short-Circuit Shutdown with Defeat Option; (10)Output Overvoltage Protection; (11)Remote Output Voltage Sense; (12)Low Shutdown IQ: 20μA; (13)5V and 3.3V Regulators; (14)3 Selectable Operating Modes: Constant Frequency, Burst Mode Operation and PWM; (15)Available in 32-Pin 5mm × 5mm QFN and 28-Pin SSOP Packages.

Diagrams

ltc3728eg/tr pin connection