LINEAR Manuals

The LT3508 is a dual current mode PWM step-down DC/DC converter with internal power switches capable of generating two 1.4A outputs.

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LTC2915/LTC2916 are low voltage single-supply monitors with selectable thresholds. The parts operate from 1.5V to 5.5V and consume a quiescent current of only 30μA. Two three-state inputs select one of nine internally programmed thresholds without the need for external resistors. For the LTC2915, an additional three-state input determines the tolerance (-5%, -10%, -15%). The tolerance for the LTC2916 is fixed at -5%. Threshold accuracy is guaranteed at ±1.5% over the entire operating temperature range. Glitch filtering ensures reliable reset operation without false triggering. The reset timeout may be set to 200ms or adjusted using an external capacitor. A separate manual reset input on the LTC2916 allows a simple push button interface. Operation to 125°C makes the LTC2915 and LTC2916 suitable for automotive applications.

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This datasheet provides information on the features of the LTC4090/LTC4090-5 USB power managers, including a 2A high voltage Bat-Track buck regulator, programmable total charge time, and an NTC thermistor input.

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The LT1220 is a high gain, high bandwidth, high precision, single-stage operational amplifier with low input bias current, low input offset voltage, high output swing, and fast settling time. It can be used in high-precision measurement, data acquisition, buffer, cable driver and other fields.

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The LT1166 is a bias generating system for controlling class AB output current in high powered amplifiers.

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The LTC3035 is a micropower, VLDO™ (very low drop-out) linear regulator which operates from input voltages as low as 1.7V. The device is capable of supplying 300mA of output current with a typical dropout voltage of only 45mV. To allow operation at low input voltages the LTC3035 includes a charge pump generator that provides the necessary bias voltage for the internal LDO circuitry. Output current comes directly from the input supply for high efficiency regulation. The charge pump bias generator requires only a 0.1µF flying capacitor and a 1µF bypass capacitor for operation. The low 0.4V internal reference voltage allows the LTC3035 to be programmed to much lower output voltages than commonly available in LDOs. The output voltage is programmed via two tiny SMD resistors. The LTC3035’s low quiescent current makes it an ideal choice for use in battery-powered systems. Other features include high output voltage.

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The LT3742 is a dual step-down DC/DC switching regulator controller from Texas Instruments. The device operates at a frequency of 500kHz and has an input voltage range of 4V to 30V. The output voltage range is 0.8V to VIN. The device uses a 2-phase antiphase output architecture to reduce output voltage ripple and minimize interference with the input supply, reducing the need for input capacitance. The device also integrates a 0.8V voltage reference and a 500kHz current mode control loop, which can provide bias power for N-channel MOSFETs and support low dropout and 100% duty cycle operation. The device also has a built-in soft-start function. The device is available in a 4mm×4mm QFN package and has a very low power consumption of only 20μA in standby mode.

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LT3500 is a monolithic 2A step-down regulator plus linear regulator/controller. It has a wide input range: 3V to 40V, which makes it suitable for a variety of power sources, including automotive batteries, 24V industrial supplies and unregulated wall adapters. The device also has resistor-programmable 250kHz to 2.2MHz frequency range and synchronization capability, which enable optimization between effi ciency and external component size. Cycle- by-cycle current limit, frequency foldback and thermal shutdown provide protection against a shorted output. Soft-start feature can control the ramp rate of the output voltage, eliminating input current surge during start-up, and also provides output tracking. LT3500 also contains an internal NPN transistor, which has feedback control and can be configured as a linear regulator or a linear regulator controller. LT3500's low current shutdown mode (<12μA) enables easy power management in battery-powered systems.

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This document describes the features and characteristics of the LTC3809 3809fb product, including no current sense resistor required, selectable spread spectrum frequency modulation, constant frequency current mode operation, etc.

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LTC1286/LTC1298 Micropower Sampling 12-Bit A/D Converters

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The LTC6702 is an extremely small dual comparator designed by LTC to maximize battery life while providing both speed and low voltage operation in applications where board space is a premium. These comparators operate on supplies between 1.7V and 5.5V, and have a maximum guaranteed propagation delay of 500ns while drawing only 30μA maximum quiescent current. Internal hysteresis desensitizes the LTC6702 to input noise and makes it easy to use, even with slow mov- ing signals. CMOS inputs allow the use of large source impedances. The LTC6702 is available in the 8-pin SOT-23 and the tiny 2mm × 2mm DFN package.

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LTC1686/LTC1687 are 52Mbps precision delay RS485 fail-safe transceivers with features including high data rate, low delay skew, high input resistance, and short-circuit protection.

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LTC4257 is a PoE PD power interface chip for IEEE 802.3af PoE system. It integrates 25k signature resistor, classification current source, input current limit with thermal foldback, undervoltage lockout and power good signalling, all in a single 8-pin package. It can be interfaced with a variety of LT DC/DC converter products to provide a cost effective power solution for IP phones, wireless access points and other PDs.

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The LT1640L/LT1640H is an 8-pin, negative voltage Hot Swap controller that allows safe board insertion and removal from a live -48V backplane. It features programmable inrush current, electronic circuit breaker, overvoltage protection, and undervoltage lockout.

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The LT1506 is a 500kHz step-down switching regulator with a constant switching frequency of 500kHz. It is easily synchronizable and operates with an input as low as 4V. The regulator uses all surface mount components and features a reduced inductor size of 1.8µH. The saturating switch design has a resistance of 0.07Ω and the shutdown current is 20µA. It also includes cycle-by-cycle current limiting. The LT1506 is optimized for lower input voltage applications and has a wide input range of 4V to 15V. It is a current mode topology with high efficiency at high switching frequency. The regulator fits into standard 7-pin DD and fused lead SO-8 packages and provides full cycle-by-cycle short-circuit protection and thermal shutdown. It can be used for both fixed output voltage and adjustable applications.

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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.

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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.

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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

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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.

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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.

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