| PMIC | 8 | Active | |
| Power Management (PMIC) | 4 | Active | |
LT193825V, 2.2A, 2.8MHz Step-Down Switching Regulator | PMIC | 4 | Active | The LT1938 is an adjustable frequency (300kHz to 2.8MHz) monolithic buck switching regulator that accepts input voltages up to 25V. A high efficiency 0.18Ω switch is included on the die along with a boost Schottky diode and the necessary oscillator, control and logic circuitry. Current mode topology is used for fast transient response and good loop stability. The LT1938's high operating frequency allows the use of small, low cost inductors and ceramic capacitors resulting in low output ripple while keeping total solution size to a minimum. The low current shutdown mode reduces input supply current to less than 1µA while a resistor and capacitor on the RUN/SS pin provide a controlled output voltage ramp (soft-start). A power good flag signals when VOUTreaches 90% of the programmed output voltage. The LT1938 is available in a 3mm × 3mm DFN package with Exposed Pad for low thermal resistance.ApplicationsAutomotive Battery RegulationPower for Portable ProductsDistributed Supply RegulationIndustrial SuppliesWall Transformer Regulation |
LT1939Monolithic 2A Step-Down Regulator Plus Linear Regulator/Controller | PMIC | 5 | Active | 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.ApplicationsAutomotive Battery RegulationIndustrial ControlWall Transformer RegulationDistributed Power Regulation |
LT1940Dual Monolithic 1.4A, 1.1MHz Step-Down Switching Regulator | PMIC | 4 | Active | The LT1940 is a dual current mode PWM step-down DC/DC converter with internal 2A power switches. Both converters are synchronized to a single 1.1MHz oscillator and run with opposite phases, reducing input ripple current. The output voltages are set with external resistor dividers, and each regulator has independent shutdown and soft-start circuits. Each regulator generates a power-good signal when its output is in regulation, easing power supply sequencing and interfacing with microcontrollers and DSPs.The LT1940’s 1.1MHz switching frequency allows the use of tiny inductors and capacitors, resulting in a very small dual 1.4A output solution. Constant frequency and ceramic capacitors combine to produce low, predictable output ripple voltage. With its wide input range of 3.6V to 25V, the LT1940 regulates a wide variety of power sources, from 4-cell batteries and 5V logic rails to unregulated wall transformers, lead acid batteries and distributed-power supplies. The LT1940L is intended to operate from regulated 5V supplies. A current mode PWM architecture provides fast transient response with simple compensation components and cycle-by-cycle current limiting. Frequency foldback and thermal shutdown provide additional protection.ApplicationsDisk DrivesDSP Power SuppliesWall Transformer RegulationDistributed Power RegulationDSL ModemsCable Modems |
LT1941Triple Monolithic Switching Regulator | Voltage Regulators - DC DC Switching Regulators | 2 | Active | The LT1941 is a triple current mode DC/DC converter with internal power switches. Two of the regulators are step-down converters with 3A and 2A power switches. The third regulator can be configured as a boost, inverter or SEPIC converter and has a 1.5A power switch. All three converters are synchronized to a 1.1MHz oscillator. The two step-down converters run with opposite phase, reducing input ripple current. The output voltages are set with external resistor dividers and each regulator has independent shutdown and soft-start circuits. Each regulator generates a power good signal when its output is in regulation, easing power supply sequencing and interfacing with microcontrollers and DSPs.The high switching frequency offers several advantages by permitting the use of small inductors and ceramic capacitors, leading to a very small triple output solution. The constant switching frequency, combined with low impedance ceramic capacitors, result in low, predictable output ripple. With its wide input voltage range of 3.5V to 25V, the LT1941 regulates a broad array of power sources from 4-cell batteries and 5V logic rails to unregulated wall transformers, lead acid batteries and distributed-power supplies.ApplicationsCable ModemsDSL ModemsDistributed Power RegulationWall Transformer RegulationDisk DrivesDSP Power |
LT1942Quad DC/DC Converter for Triple Output TFT Supply Plus LED Driver | Power Management (PMIC) | 2 | Active | The LT1942 is a highly integrated quad switching regulator designed to provide all necessary power supply functions for TFT displays, including the white LED backlight driver. The TFT supply incorporates two boost and one inverting DC/DC converters. The TFT supply output voltages are independently set, unlike charge pump solutions which have many limitations. Power sequencing for the TFT supply is built into the part and is user programmable.The LED driver is a boost DC/DC converter that can be independently controlled. The LED driver has built-in dimming control for precise control of LED current. An 8:1 dimming range is achieved by adjusting the CTRL4 voltage. The user can elect to drive a single string or two strings of LEDs. An LED ballast circuit is included to precisely match the LED currents if two strings of LEDs are used. Soft-start is built into the LED driver as well as the primary TFT supply.The LT1942 is available in a low profile (0.75mm) 24-lead QFN (4mm × 4mm) package.ApplicationsPoly-Silicon TFT DisplaysAmorphous Silicon TFT Displays |
LT1943High Current Quad Output Regulator for TFT LCD Panels | Integrated Circuits (ICs) | 2 | Active | The LT1943 quad output adjustable switching regulator provides power for large TFT LCD panels. The device, housed in a low profile 28 pin thermally enhanced TSSOP package, can generate a 3.3V or 5V logic supply along with the triple output supply required for the TFT LCD panel. Operating from an input range of 4.5V to 22V, a step-down regulator provides a low voltage output VLOGICwith up to 2A current. A high-power step-up converter, a lowerpower step-up converter and an inverting converter provide the three independent output voltages AVDD, VONand VOFFrequired by the LCD panel. A high-side PNP provides delayed turn-on of the VONsignal and can handle up to 30mA. Protection circuitry ensures that VONis disabled if any of the four outputs are more than 10% below the programmed voltage.All switchers are synchronized to an internal 1.2MHz clock, allowing the use of low profile inductors and ceramic capacitors throughout. A current mode architecture provides excellent transient response. For best flexibility, all outputs are adjustable. Soft-start is included in all four channels. APGOODpin can drive an optional PMOS pass device to provide output disconnect for the AVDDoutput.ApplicationsLarge TFT-LCD Desktop MonitorsFlat Panel Televisions |
| Voltage Regulators - DC DC Switching Regulators | 2 | Active | |
LT1944-1Dual Micropower Step-Up DC/DC Converter | Integrated Circuits (ICs) | 2 | Active | The LT1944-1 is a dual micropower step-up DC/DC converter in a 10-pin MSOP package. One converter is designed with a 100mA current limit and a 400ns off-time; the other with a 175mA current limit and a 1.5µs off-time. The 1.5µs off-time converter is ideal for generating an output voltage that is close to the input voltage (i.e. a Li-Ion to 5V converter, or a two-cell to 3.3V converter). With an input voltage range of 1.2V to 15V, the LT1944-1 is ideal for a wide variety of applications. Both converters feature a quiescent current of only 20µA at no load, which further reduces to 0.5µA in shutdown. A current limited, fixed off-time control scheme conserves operating current, resulting in high efficiency over a broad range of load current. Tiny, low profile inductors and capacitors can be used to minimize footprint and cost in space-conscious portable applications.Switch CurrentLT1944350mA, 350mALT1944-1100mA, 175mAApplicationsSmall TFT LCD PanelsHandheld ComputersBattery BackupDigital Cameras |
