LTC3707

` 180° Phased Dual Controllers Reduce Required Input Capacitance and Power Supply Induced Noise
` OPTI-LOOP^® Compensation Minimizes COUT
` ±1.5% Output Voltage Accuracy over Temperature
` Dual N-Channel MOSFET Synchronous Drive
` Power Good Output Voltage Monitor
` DC Programmed Fixed Frequency 150kHz to 300kHz
` Wide VIN Range: 4.5V to 28V Operation
` Very Low Dropout Operation: 99% Duty Cycle
` Adjustable Soft-Start Current Ramping
` Foldback Output Current Limiting
` Latched Short-Circuit Shutdown with Defeat Option
` Output Overvoltage Protection
` Remote Output Voltage Sense
` Low Shutdown I_Q: 20A
` 5V and 3.3V Standby Regulators
` Small 28-Lead Narrow SSOP Package
` Selectable Constant Frequency, Burst Mode^® Operation or PWM Operation

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

Input Supply Voltage (V_IN).........................30V to 0.3V
Top Side Driver Voltages
(BOOST1, BOOST2) ...................................36V to 0.3V
Switch Voltage (SW1, SW2) .........................30V to 5V
INTV_CC, EXTV_CC, RUN/SS1, RUN/SS2, (BOOST1-SW1),
(BOOST2-SW2), PGOOD .............................7V to 0.3V
SENSE1+, SENSE2 +, SENSE1,
SENSE2 Voltages ..................... (1.1)INTV_CC to 0.3V
FREQSET, STBYMD, FCB Voltage ........ INTV_CC to 0.3V
I_TH1, I_TH2, V_OSENSE1, V_OSENSE2 Voltages..2.7V to 0.3V
Peak Output Current <10ms (TG1, TG2, BG1, BG2) .. 3A
INTV_CC Peak Output Current ............................... 40mA
Operating Temperature Range
LTC3707EG (Note 2) .......................... 40°C to 85°C
Junction Temperature (Note 3) .......................... 125°C
Storage Temperature Range ........... 65°C to 150°C
Lead Temperature (Soldering, 10 sec)............... 300°C

The LTC^®3707 is a high performance dual step-down switching regulator controller that drives N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows adjustment of the frequency up to 300kHz. Power loss and noise due to the ESR of the input capacitors are minimized by operating the two controller output stages out of phase.

OPTI-LOOP compensation of LTC3707 allows the transient response to be optimized over a wide range of output capacitance and ESR values. The precision 0.8V reference and power good output indicator are compatible with future microprocessor generations, and a wide 3.5V to 30V input supply range encompasses all battery chemistries.

A RUN/SS pin for each controller provides both soft-start and optional timed, short-circuit shutdown. Current foldback of LTC3707 limits MOSFET dissipation during short-circuit conditions when overcurrent latchoff is disabled. Output overvoltage protection circuitry latches on the bottom MOSFET until V_OUT returns to normal. The FCB mode pin can select among Burst Mode operation, constant frequency mode and continuous inductor current mode or regulate a secondary winding.