LINEAR Manuals

The LT1339 is a high power synchronous current mode switching regulator controller. The IC drives dual N-channel MOSFETs to create a single IC solution for high power DC/DC converters in applications up to 60V. The LT1339 incorporates programmable average current limiting, allowing accurate limiting of DC load current independent of inductor ripple current. The IC also incorporates user-adjustable slope compensation for minimization of magnetics at duty cycles up to 90%. The LT1339 timing oscillator operating frequency is programmable and can be synchronized up to 150kHz. Minimum off-time operation provides main switch protection. The IC also incorporates a soft start feature that is gated by both shutdown and undervoltage lockout conditions. An output phase reversal pin allows flexibility in configuration of converter types, including inverting and negative topologies.

The LT3501 is a dual current mode PWM step-down DC/DC converter with two internal 3.5A switches. It features independent input voltage, feedback, soft-start, and power good pins for each channel, simplifying complex power supply tracking/sequencing requirements. The converters can be synchronized to a common external clock input or a resistor programmable fixed 250kHz to 1.5MHz internal oscillator. The channels maintain a 180° phase relationship at all frequencies, reducing voltage ripple and component size. The programmable frequency allows for optimization between efficiency and external component size. The switch can stay on through multiple clock cycles, only switching off when the boost capacitor needs recharging, resulting in a maximum duty cycle of ~95% and improved minimum input-to-output voltage ratios. Each output can be independently disabled using its own soft-start pin, or the entire part can be placed in low quiescent current shutdown mode using the SHDN pin. The LT3501 is available in a 20-lead TSSOP package with an exposed leadframe for low thermal resistance.

This document introduces the features of the LTC4081 lithium-ion battery charger, including constant current constant voltage, NTC temperature detection, automatic charging, soft start and other functions

The LTC1649 is a high power, high efficiency switching regulator controller optimized for use with very low supply voltages. It operates from 2.7V to 5V input, and provides a regulated output voltage from 1.26V to 2.5V at up to 20A load current. A typical 3.3V to 2.5V application features efficiency above 90% from 1A to 10A load. The LTC1649 uses a pair of standard 5V logic-level N-channel external MOSFETs, eliminating the need for expensive P-channel or super-low-threshold devices. The LTC1649 shares its internal switching architecture with the LTC1430, and features the same ±1% line, load and temperature regulation characteristics. Current limit is user-adjustable without requiring an external low-value sense resistor.

The LT3010/LT3010-5 is a high voltage, micropower low dropout linear regulator capable of supplying 50mA output current with a dropout voltage of 300mV. Designed for use in battery-powered or high voltage systems, the low quiescent current (30μA operating and 1μA in shutdown) makes the LT3010 an ideal choice. Quiescent current is also well controlled in dropout. Other features of the LT3010 include the ability to operate with very small output capacitors. The regulators are stable with only 1μF on the output while most older devices re- quire between 10μF and 100μF for stability. Small ceramic capacitors can be used without the necessary addition of ESR as is common with other regulators. Internal protec- tion circuitry includes reverse-battery protection, current limiting, thermal limiting and reverse current protection. The device is available in a fi xed output voltage of 5V and as an adjustable device with a 1.275V reference voltage. The LT3010 regulator is available in the 8-lead MSOP pack- age with an exposed pad for enhanced thermal handling capability.

The LT1425 is a monolithic high power switching regulator specifically designed for the isolated flyback topology. No “third winding” or optoisolator is required; the integrated circuit senses the isolated output voltage directly from the primary side flyback waveform. A high current, high efficiency switch is included on the die along with all oscillator, control and protection circuitry. The LT1425 operates with input supply voltages from 3V to 20V and draws only 7mA quiescent current. It can deliver output power up to 6W with no external power devices. By utilizing current mode switching techniques, it provides excellent AC and DC line regulation. The LT1425 has a number of features not found on other switching regulator ICs. Its unique control circuitry can maintain regulation well into discontinuous mode in most applications. Optional load compensation circuitry allows for improved load regulation. An externally activated shutdown mode reduces total supply current to 15µA for standby operation.

This document is about LT1676, which is a wide input range, high efficiency Buck (step-down) switching regulator. The part can accept input voltages as high as 60V and contains an output switch rated at 700mA peak current.

The LTC1553 is a high power, high efficiency switching regulator controller optimized for 5V or 12V input to 1.8V-3.5V output applications. It features a digitally programmable output voltage, a precision internal reference, and an internal feedback system that provides output accuracy of ±1.5% at room temperature and typically ±2% over-temperature, load current, and line voltage shifts. The LTC1553 uses a synchronous switching architecture with two external N-channel output devices, providing high efficiency and eliminating the need for a high power, high-cost P-channel device. Additionally, it senses the output current across the on-resistance of the upper N-channel FET, providing an adjustable current limit without an external low-value sense resistor.

The LTC3809 is a synchronous step-down switching regulator controller that drives external complementary power MOSFETs using few external components. It features selectable spread spectrum frequency modulation for low noise operation, constant frequency current mode operation for excellent line and load transient response, and true PLL for frequency locking or adjustment. It has a wide input voltage range and output voltage range, and is suitable for one or two lithium-ion powered devices, portable instruments, and distributed DC power systems.

This datasheet introduces the LTC4101, a single chip smart battery charger controller that is 100% compliant (Rev. 1.1) SMBus support that allows operation with or without a host. It has up to 4A charging current capability, high efficiency synchronous buck charger, VBAT optimized 3V to 5.5V, SMBus accelerator improves SMBus timing, hardware interrupt and SMBAlert response eliminate interrupt polling, 0.5V dropout voltage, maximum duty cycle>98%, AC adapter current limit maximizes charge rate, ±0.8% voltage accuracy, ±4% current accuracy, 10-bit DAC for charge current programming, 11-bit DAC for charger voltage programming, user-selectable overvoltage and overcurrent limits, high noise immunity SafetySignal sensor, 24-pin SSOP package.

LTC2927 is a single power supply tracking controller from LTC company, which can achieve VCORE and VI/O power tracking, suitable for microprocessor, DSP and FPGA power supplies, supporting multiple power supply systems, power tracking, power sequencing and other functions.

The LTC1983-3 and LTC1983-5 are inverting charge pump DC/DC converters that produce negative regulated outputs. The parts require only three tiny external capacitors and can provide up to 100mA of output current. The devices can operate in open loop mode (creating a –VIN supply) or regulated output mode depending on the input supply voltage and the output current. The LTC1983-3/LTC1983-5 have many useful features for portable applications including very low quiescent current (25µA typical) and a zero current shutdown mode programmed through the SHDN pin. The LTC1983-3/LTC1983-5 are over-temperature and short-circuit protected. The parts are available in a 6-pin low profile (1mm) ThinSOT package.

The LTC4060 is a complete fast charging system for NiMH or NiCd batteries. Just a few external components are needed to design a standalone linear charging system. An external PNP transistor provides charge current that is user programmable with a resistor. A small external capacitor is also needed to provide precharge.