LTC3802

Features:

` Wide V<sub>IN</sub> Range: 3V to 30V Operation with Line Feedforward Compensation
` Leading Edge Modulation Architecture for Extremely Low Duty Cycle Operation
`Phase-Lockable Fixed Frequency: 330kHz to 750kHz
` Two 180° Out-of-Phase Controllers
` Fast Programmable Power-Up/-Down Tracking
` Programmable Current Limit Without External Current Sense Resistor
` Optional Burst Mode<sup>®</sup> Operation at Light Load
` ±1% 0.6V Voltage Reference
` External N-Channel MOSFET Architecture
` Low Shutdown Current: <100A
` Overvoltage Protection and PGOOD Flag
` Small 28-Lead SSOP and 32-Lead QFN Packages


Application

· Notebook and Palmtop Computers
· Portable Instruments
· Battery-Operated Digital Devices
· DC Power Distribution Systems


Pinout




Specifications

Supply Voltage
    V_CC, PV_CC .................................................................. 7V
    BOOST n.................................................................... 37V
    BOOST n SW n......................................................... 7V
    SW n.............................................................. 1V to 30V
Input Voltage
    V_INFF .......................................................................... 30V
    FB n, CMPIN n, FBT, PLLIN, FCB,
    RUN/SS, PGOOD, PLLLPF, PHASEMD,
    EXTREF, I_MAX n.................................. 0.3V to VCC + 0.3V
Extended Commercial
Operating Temperature Range (Note 2) .. ......40°C to 85
Storage Temperature Range
    LTC3802EGN .............................................. 65 to 150
    LTC3802EUH .............................................. 65 to 125
Lead Temperature (Soldering, 10 sec)
    LTC3802EGN Only ..................................................... 300


Description

The LTC®3802 is a dual switching regulator controller optimized for high efficiency step-down conversion from input voltages between 3V to 30V. The controller uses a leading edge modulation scheme to allow extremely low duty cycle operation. The constant frequency voltage mode controller allows a phase-lockable frequency between 330kHz and 750kHz. Power loss and noise due to the ESR of the input capacitors are minimized by operating the two controller output stages 180°out of phase. The synchronous buck architecture automatically shifts to Burst Mode operation as the output load decreases, ensuring maximum efficiency over a wide range of load currents.

The LTC3802 features an onboard, trimmed 0.6V reference and provides better than 1% regulation at the converter outputs. A separate output sense provides real time overvoltage protection and PGOOD sensing. An FBT pin programs the power-up/-down tracking between the two channels to meet various sequencing requirements. A RUN/SS pin provides soft-start and externally programmable current limit protection functions.