The LTC1700 is a current mode synchronous step-up DC/DC controller that drives external N-channel and P-channel power MOSFETs using a constant frequency PWM architecture. Current limiting is provided by sensing the voltage drop across the main MOSFET, eliminating the need of a sense resistor. This No RSENSE? technique helps the LTC1700 maintain high efficiency at heavy loads while Burst Mode operation ensures high efficiency at light loads, thus providing high efficiencies over a wide range of load currents.The LTC1700 operates at a minimum input voltage as low as 0.9V. The device boasts a ?1.5% output voltage accuracy and consumes only 200?A of quiescent current. In shutdown, it only draws 10?A.To prevent inductor current runaway, the duty cycle is limited to 90%. Overvoltage protection is also provided which shuts both the external MOSFETs off when tripped.High constant operating frequency of 530kHz allows the use of small inductors and output capacitors. The LTC1700 can also be synchronized between 400kHz to 750kHz. Burst Mode operation is inhibited when the device is externally clocked or when the SYNC/MODE pin is pulled low to reduce noise and RF interference.Applications Cellular Telephones Wireless Modems RF Communications 2.5V to 3.3V, 2.5V to 5V Converters Battery-Powered Equipment Telecom/Network Systems

The LTC1734 is a low cost, single cell, constant-current/constant-voltage Li-Ion battery charger controller. When combined with a few external components, the SOT-23 package forms a very small, low cost charger for single cell lithium-ion batteries.The LTC1734 is available in 4.1V and 4.2V versions with 1% accuracy. Constant current is programmed using a single external resistor between the PROG pin and ground. Manual shutdown is accomplished by floating the program resistor while removing input power automatically puts the LT1734 into sleep mode. Both the shutdown and sleep modes drain near zero current from battery.Charge current can be monitored via the voltage on the PROG pin allowing a microcontroller or ADC to read the current and determine when to terminate the charge cycle. The output driver is both current limited and thermally protected to prevent the LTC1734 from operating outside of safe limits. No external blocking diode is required.The LTC1734 can also function as a general purpose current source or as a current source for charging nickel-cadmium (NiCd) and nickel-metal-hydride (NiMH) batteries using external termination. Charge Current Vfloat LTC1734 180mA to 700mA 4.1V or 4.2V LTC1734L 50mA to 180mA 4.2V Applications Cellular Telephones Handheld Computers Digital Cameras Charging Docks and Cradles Low Cost and Small Size Chargers Programmable Current Source

The LTC3201 is an ultralow noise, constant frequency, charge pump DC/DC converter specifically designed for powering white LEDs. The part produces a low noise boosted supply capable of supplying 100mA of output current. LED current is regulated for accurate and stable backlighting. A 3-bit DAC provides output current adjust for brightness control.Low external parts count (one small flying capacitor and three small bypass capacitors) and small MSOP-10 package size make the LTC3201 ideally suited for space constrained applications. An input noise filter further reduces input noise, thus enabling direct connection to the battery. High switching frequency enables the use of small external capacitors.The LTC3201 contains overtemperature protection and can survive an indefinite output short to GND. Internal soft-start circuitry also prevents excessive inrush current on start-up. A low current shutdown feature disconnects the load from VIN and reduces quiescent current to less than 1?A.Applications White LED Backlighting Programmable Boost Current Source

The LTC1730 is a complete pulse charger for 1-cell lithium-ion batteries. When charging a depleted cell, the internal MOSFET is fully on allowing the current limited input power source to provide charge current to the battery, virtually eliminating heat generation in the charger.As the battery accepts charge and approaches the programmed voltage, the internal MOSFET begins switching off and on with the duty cycle gradually decreasing as the battery approaches a fully charged condition. A programmable timer ends the charge cycle. The end-of-charge condition is indicated at the CHRG pin when the average charge current falls to C/10. Removing the input voltage puts the LTC1730 into a sleep mode, dropping the battery current drain to less than 1?A (maximum).An external sense resistor limits the maximum charge current as a safety precaution against a user connecting a wall adapter with the incorrect or no current limit. The internal MOSFET prevents reverse battery current from flowing if the input voltage is shorted to ground, eliminating the need for a blocking diode.The LTC1730-4 is available in the 16-pin SSOP package and the LTC1730-4.2 is available in the 8-pin SO package.Applications Standalone Lithium-Ion Battery Charger Handheld Computers Cellular Telephones

The LTC1923 is a pulse width modulator intended for thermoelectric cooler (TEC) or heater applications requiring either unidirectional or bidirectional drive circuits. All of the necessary control circuitry and two sets of complementary output drivers are integrated into the LTC1923 to drive a full bridge, providing an efficient means of bidirectional current flow to the TEC. An accurate temperature control loop to stabilize the temperature of a laser diode system is easily achieved with the addition of just a few external components. Typical temperature setpoint accuracy of 0.1?C is achievable with the LTC1923. Adding an instrumentation amplifier front end allows setpoint stability of 0.01?C.The part features independent adjustable heating and cooling pulse-by-pulse current limit, current soft-start for controlled start-up, output slew rate control to reduce system noise, differential current sense and voltage amplifiers and a host of auxiliary circuits to protect the laser and provide redundant system monitoring.Applications Laser-Based Fiber Optic Links Medical Instruments CPU Temperature Regulators

DC391A-A: Demo Board for LTC5505 RF Power Detector with Buffered Output and >40dB Dynamic Range.

The LT1961 is a 1.25MHz monolithic boost switching regulator. A high efficiency 1.5A, 0.2? switch is included on the die together with all the control circuitry required to complete a high frequency, current-mode switching regulator. Current-mode control provides fast transient response and excellent loop stability.New design techniques achieve high efficiency at high switching frequencies over a wide operating voltage range. A low dropout internal regulator maintains consistent performance over a wide range of inputs from 24V systems to Li-Ion batteries. An operating supply current of 1mA maintains high efficiency, especially at lower output currents. Shutdown reduces quiescent current to 6?A. Maximum switch current remains constant at all duty cycles. Synchronization allows an external logic level signal to increase the internal oscillator from 1.5MHz to 2MHz.The LT1961 is available in an exposed pad, 8-pin MSOP package. Full cycle-by-cycle switch current limit protection and thermal shutdown are provided. High frequency operation allows the reduction of input and output filtering components and permits the use of chip inductors.Applications DSL Modems Portable Computers Battery-Powered Systems Distributed Power

DC442A: Demo Board for the LT1950 Single Switch PWM Controller with Auxiliary Boost Converter.

The LT1970A is a ?500mA power op amp with precise externally controlled current limiting. Separate control voltages program the sourcing and sinking current limit sense thresholds with 1% accuracy. Output current may be boosted by adding external power transistors.The circuit operates with single or split power supplies from 5V to 36V total supply voltage. In normal operation, the input stage supplies and the output stage supplies are connected (VCC to V+ and VEE to V?). To reduce power dissipation it is possible to power the output stage (V+, V?) from independent, lower voltage rails. The amplifier is unity-gain stable with a 3.6MHz gain-bandwidth product and slews at 1.6V/?s. The LT1970A can drive capacitive and inductive loads directly.Open-collector status flags signal current limit circuit activation, as well as thermal shutdown of the amplifier. An enable logic input puts the amplifier into a low power, high impedance output state when pulled low. Thermal shutdown and a ?800mA fixed current limit protect the chip under fault conditions.The LT1970A is packaged in a 20-lead TSSOP package with a thermally conductive copper bottom plate to facilitate heat sinking.Applications Automatic Test Equipment Laboratory Power Supplies Motor Drivers Thermoelectric Cooler Driver

DC459A Demo Board for: LT1946 1.2MHz Boost DC/DC Converter with 1.5A Switch and Soft-Start LT1946A 2.7MHz Boost DC/DC Converter with 1.5A Switch and Soft-Start