High Efficiency Step-Down Switching Regulator Controllers Features: Very High Efficiency: Over 95% Possible Wide VIN Range: 3.5V to 16V Current Mode Operation for Excellent Line and Load Transient Response High Efficiency Maintained Over Three Decades of Output Current Low 160µA Standby Current at Light Loads Logic Controlled Micropower Shutdown: IQ <20µA Short-Circuit Protection Very Low Dropout Operation: 100% Duty Cycle High Efficiency in a Small Amount of Board Space Output Can Be Externally Held High in Shutdown Available in 8-Pin SO Package

High Efficiency Synchronous Step-Down Switching Regulators Features: Ultra-High Efficiency: Over 95% Possible Current-Mode Operation for Excellent Line and Load Transient Response High Efficiency Maintained Over Three Decades of Output Current Low 160µA Standby Current at Light Loads Logic Controlled Micropower Shutdown: IQ <20µA Wide VIN Range: 3.5V to 20V Short-Circuit Protection Very Low Dropout Operation: 100% Duty Cycle Synchronous FET Switching for High Efficiency Adaptive Nonoverlap Gate Drives Output Can Be Externally Held High in Shutdown Available in 14-Pin Narrow SO Package

Switching Voltage Regulators Boost/SEPIC/Inverting DC/DC Converter with 65V Switch, Soft-Start and Synchronization

105V, 1A Low EMI Synchronous Step-Down Regulator with Fast Current Programming PassThru Features: Wide VIN Range: 4.4V to 105V (110V Abs Max) Ultralow EMI/EMC Emissions: CISPR 25 Compliant 2µA IQ When Regulating 48VIN to 3.3VOUT Fast and Accurate Output Current Programming and Monitoring with No External RSENSE Brick Wall Current Limit Low Minimum On-Time: 35ns Wide VOUT Range: 1V to VIN 100% Maximum Duty Cycle Operation Programmable Fixed Frequency: 200kHz to 2MHz Eight, Pin-Selectable Fixed (1.2V to 15V) or Adjustable Output Voltages Selectable Continuous, Pulse-Skipping, or Low Ripple Burst Mode® Operation at Light Loads PLL Synchronization to External Clock EXTVCC LDO Powers Chip from VOUT = 3.3V to 40V OPTI-LOOP® or Fixed Internal Compensation Input and Output Overvoltage Protection Thermally Enhanced (5mm × 6mm) QFN Package

105V, 1A Low EMI Synchronous Step-Down Regulator with Fast Current Programming PassThru Features: Wide VIN Range: 4.4V to 105V (110V Abs Max) Ultralow EMI/EMC Emissions: CISPR 25 Compliant 2µA IQ When Regulating 48VIN to 3.3VOUT Fast and Accurate Output Current Programming and Monitoring with No External RSENSE Brick Wall Current Limit Low Minimum On-Time: 35ns Wide VOUT Range: 1V to VIN 100% Maximum Duty Cycle Operation Programmable Fixed Frequency: 200kHz to 2MHz Eight, Pin-Selectable Fixed (1.2V to 15V) or Adjustable Output Voltages Selectable Continuous, Pulse-Skipping, or Low Ripple Burst Mode® Operation at Light Loads PLL Synchronization to External Clock EXTVCC LDO Powers Chip from VOUT = 3.3V to 40V OPTI-LOOP® or Fixed Internal Compensation Input and Output Overvoltage Protection Thermally Enhanced (5mm × 6mm) QFN Package

100VIN Micropower Isolated Flyback Converter with 150V/260mA Switch Features: 6V to 100V Input Voltage Range 260mA, 150V Internal DMOS Power Switch Low Quiescent Current 70µA in Sleep Mode 330µA in Active Mode Boundary Mode Operation at Heavy Load Low-Ripple Burst Mode® Operation at Light Load Minimum Load <0.5% (Typ) of Full Output VOUT Set with a Single External Resistor No Transformer Third Winding or Opto-Isolator Required for Regulation Accurate EN/UVLO Threshold and Hysteresis Internal Compensation and Soft-Start 5-Lead TSOT-23 Package AEC-Q100 Qualified for Automotive Applications

42V, 1.5A Synchronous Step-Down Regulator with 3A Quiescent Current Features: Silent Switcher® 2 Architecture Ultralow EMI/EMC Emissions on Any PCB Eliminates PCB Layout Sensitivity Internal Bypass Capacitors Reduce Radiated EMI Optional Spread Spectrum Modulation Wide Input Voltage Range: 3.0V to 42V Ultralow Quiescent Current Burst Mode® Operation: <3μA IQ Regulating 12VIN to 3.3VOUT Output Ripple <10mVP-P High Efficiency 2MHz Synchronous Operation: >90% Efficiency at 0.75A, 5VOUT from 12VIN 1.5A Continuous Output Current Fast Minimum Switch-On Time: 35ns Adjustable and Synchronizable: 200kHz to 2.2MHz Allows Use of Small Inductors Low Dropout Peak Current Mode Operation Internal Compensation Output Soft-Start and Tracking Small 12-Lead LQFN Package

65V, 2A Synchronous Step-Down Regulator with 2.5A Quiescent Current Features: Wide Input Voltage Range: 3.4V to 65V Ultralow Quiescent Current Burst Mode® Operation: 2.5μA IQ Regulating 12VIN to 3.3VOUT  Output Ripple < 10mVP-P High Efficiency Synchronous Operation: 94% Efficiency at 1A, 12VIN to 5VOUT 92% Efficiency at 1A, 12VIN to 3.3VOUT Fast 30ns Minimum Switch-On Time Low Dropout Under All Conditions: 250mV at 1A Safely Tolerates Inductor Saturation in Overload Low EMI Adjustable and Synchronizable: 200kHz to 2.2MHz Accurate 1V Enable Pin Threshold Internal Compensation Output Soft-Start and Tracking Small Thermally Enhanced 16-Lead MSOP and 24-Lead 3mm × 5mm QFN Packages

The LTC2953 is a push button On/Off controller that manages system power via a push button interface. An enable output toggles system power while an interrupt output provides debounced push button status. The interrupt output can be used in menu driven applications to request a system power down. The LTC2953 also features input and output power supply monitors. An uncommitted power fail comparator provides real time input monitor information, while a de-glitched under voltage lockout comparator gracefully initiates a system power down. The under voltage lockout comparator prevents the system from powering from a low power supply. The adjustable supply monitor input is compared against an accurate internal 0.5V reference. The reset output remains low until the supply monitor input has been in compliance for 200ms. The LTC2953 operates over a wide 2.7V to 27V input voltage range and draws only 14µA of current. Two versions of the part accommodate either positive or negative enable polarities. Applications Push Button Power Path Control Battery Power Supervisor Portable Instrumentation, PDA Blade Servers Desktop and Notebook Computers

The LT1939 is a current mode PWM step-down DC/DC converter with an internal 2.3A switch. The wide input range of 3V to 25V makes the LT1939 suitable for regulating power from a wide variety of sources, including automotive batteries, industrial supplies and unregulated wall adapters.Resistor-programmable 250kHz to 2.2MHz frequency range and synchronization capability enable optimization between efficiency and external component size. Cycle-by-cycle current limit, frequency foldback and thermal shutdown provide protection against a shorted output. The soft-start feature controls the ramp rate of the output voltage, eliminating input current surge during start-up, and also provides output tracking.The LT1939 contains an internal NPN transistor with feedback control which can be configured as a linear regulator or as a linear regulator controller.The LT1939’s low current shutdown mode (<12μA) enables easy power management in battery-powered systems.Applications Automotive Battery Regulation Industrial Control Wall Transformer Regulation Distributed Power Regulation