Analog Devices Inc./Maxim Integrated

The LTC3600 is a high efficiency, monolithic synchronous buck regulator whose output is programmed with just one external resistor. The accurate internally generated 50μA current source on the ISETpin allows the use of a single external resistor to program an output voltage that ranges from 0V to 0.5V below VIN. The VOUTvoltage feeds directly back to the error amplifier in unity gain fashion and equals the ISETvoltage. The operating supply voltage range is 4V to 15V, making it suitable for dual lithium-ion battery and 5V or 12V input point-of-load power supply applications.The operating frequency is synchronizable to an external clock or programmable from 200kHz to 4MHz with an external resistor. High switching frequency allows the use of small surface mount inductors. The unique constant on-time architecture is ideal for operating at high frequency in high step-down ratio applications that also demand fast load transient response.ApplicationsVoltage Tracking SuppliesPoint-of-Load Power SuppliesPortable InstrumentsDistributed Power Systems

The LTC3601 is a high efficiency, monolithic synchronous buck regulator using a phase-lockable controlled on-time, current mode architecture capable of supplying up to 1.5A of output current. The operating supply voltage range is from 4V to 15V, making it suitable for a wide range of power supply applications.The operating frequency is programmable from 800kHz to 4MHz with an external resistor enabling the use of small surface mount inductors. For switching noise sensitive applications, the LTC3601 can be externally synchronized over the same frequency range. An internal phase-locked loop aligns the on-time of the top power MOSFET to the internal or external clock. This unique constant frequency/ controlled on-time architecture is ideal for high step-down ratio applications that demand high switching frequencies and fast transient response.The LTC3601 offers two operational modes: Burst Mode operation and forced continuous mode to allow the user to optimize output voltage ripple, noise, and light load efficiency for a given application. Maximum light load efficiency is achieved with the selection of Burst Mode operation while forced continuous mode provides minimum output ripple and constant frequency operation.ApplicationsDistributed Power SystemsLithium-Ion Battery-Powered InstrumentsPoint-of-Load Power Supply

The LTC3603 is a high efficiency, monolithic synchronous step-down DC/DC converter utilizing a constant-frequency, current mode architecture. It operates from an input voltage range of 4.5V to 15V and provides an adjustable regulated output voltage from 0.6V to 14.5V while delivering up to 2.5A of output current. The internal synchronous power switch with 45mΩ on-resistance increases efficiency and eliminates the need for an external Schottky diode. The switching frequency can either be set by an external resistor or synchronized to an external clock. OPTI-LOOP®compensation allows the transient response to be optimized over a wide range of loads and output capacitors.The LTC3603 can be configured for either Burst Mode operation or forced continuous operation. Forced continuous operation reduces noise and RF interference, while Burst Mode operation provides the highest efficiency at light loads. In Burst Mode operation, external control of the burst clamp level allows the output voltage ripple to be adjusted according to the requirements of the application.ApplicationsPoint-of-Load SuppliesPortable InstrumentsCommunications Infrastructure

The LTC3606B is an 800mA monolithic synchronous buck regulator using a constant frequency current mode architecture.The input supply voltage range is 2.5V to 5.5V, making it ideal for Li-Ion and USB powered applications. 100% duty cycle capability provides low dropout operation, extending the run time in battery-operated systems. Low output voltages are supported with the 0.6V feedback reference voltage. The LTC3606B can supply 800mA output current.The LTC3606B’s programmable average input current limit is ideal for USB applications and for point-of-load power supplies because the LTC3606B’s limited input current will still allow its output to deliver high peak load currents without collapsing the input supply. The operating frequency is internally set at 2.25MHz allowing the use of small surface mount inductors. Internal soft-start reduces in-rush current during start-up. The LTC3606B is available in an 8-Lead 3mm × 3mm DFN package.ApplicationsHigh Peak Load Current ApplicationsUSB Powered DevicesSupercapacitor ChargingRadio Transmitters and Other Handheld Devices