Analog Devices Inc./Maxim Integrated

The LT3480 is an adjustable frequency (200kHz to 2.4MHz) monolithic buck switching regulator that accepts input voltages up to 36V (60V maximum). A high efficiency 0.25Ω 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. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping output ripple below 15mV in a typical application. In addition, the LT3480 can further enhance low output current efficiency by drawing bias current from the output when VOUTis above 3V. Shutdown 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 86% of the programmed output voltage. The LT3480 is available in 10-Pin MSOP and 3mm × 3mm DFN packages with exposed pads for low thermal resistance.ApplicationsAutomotive Battery RegulationPower for Portable ProductsDistributed Supply RegulationIndustrial Supplies

The LT3484 family of photoflash capacitor charger ICs is designed for use in digital camera and mobile phone applications where space is at a premium. The LT3484's patented control technique allows it to use extremely small transformers, and the improved NPN power switch requires no external Schottky diode clamp, reducing solution size. Output voltage detection requires no external circuitry as the transformer turns ratio determines final charge voltage.The devices feature a VBATpin, which allows the use of 2 alkaline cells to charge the capacitor. The LT3484-0, -2 and -1 have primary current limits of 1.4A, 1A and 0.7A respectively, resulting in tightly controlled average input current of 500mA, 350mA and 225mA respectively. The three versions are otherwise identical.The CHARGE pin gives full control of the part to the user. Driving CHARGE low puts the part in shutdown. TheDONEpin indicates when the part has completed charging. The LT3484 series of parts are housed in a tiny low profile 2mm × 3mm DFN package.ApplicationsDigital Camera and Cell Phone Flash Charger

The LT3485 family of photoflash chargers are highly integrated ICs containing complete charger and IGBT drive functions. The patented control technique of the LT3485-x allows it to use extremely small transformers. Output voltage detection requires no external circuitry. The turns ratio of the transformer controls the final charge voltage. While charging, the output voltage on the capacitor may be monitored by a microcontroller from the monitor pin. Each device contains an on-chip high voltage NPN power switch, which can withstand negative voltages on the switch pin without an external Schottky diode. The device features a VBATpin, which allows the use of two AA cells to charge the capacitor. The internal circuitry operates from the VINpin. The LT3485-0 has a primary current limit of 1.4A, whereas the LT3485-3, LT3485-2, and LT3485-1 have current limits of 2A, 1A and 0.7A respectively. These different current limits result in tightly controlled input currents.The CHARGE pin gives full control of the part to the user. Driving CHARGE low puts the part in shutdown. TheDONEpin indicates when the part has completed charging. The LT3485 series of parts are housed in a leadless (3mm × 3mm) DFN package.ApplicationsDigital Camera and Cell Phone Flash Charger

The LT3487 dual channel switching regulator generates positive and negative outputs for biasing CCD imagers. The device delivers up to –8V at 90mA and 15V at 45mA from a lithium-ion cell, providing bias for many popular CCD imagers. The boost regulator incorporates output disconnect technology to eliminate the DC current path from VINto the output load that is present in standard boost configurations. The 2MHz switching frequency allows CCD solutions using tiny, low profile capacitors and inductors and generates low noise outputs that are easy to filter. Schottky diodes are internal and the output voltages are set with one resistor per channel, reducing the external component count.Intelligent soft-start allows sequential soft-start of the two channels with a single capacitor. The soft-start is sequenced such that the output ramp of the negative channel begins after the ramp of the positive channel. Internal sequencing circuitry also disables the negative channel until the positive channel has reached 87% of its final value, ensuring that the sum of the two outputs is always positive.The LT3487 is available in a 10-pin 3mm × 3mm DFN package.ApplicationsCCD BiasTFT LCD BiasOLED Bias±Rail Generation for Op Amps

The LT3489 is a fixed frequency step-up DC/DC converter containing an internal 2.5A, 40V switch. The LT3489 is ideal for large TFT-LCD panel power supplies. The LT3489 switches at 2MHz, allowing the use of tiny, low profile inductors and low value ceramic capacitors. Loop compensation can be either internal or external, giving the user flexibility in setting loop compensation and allowing optimized transient response with low ESR ceramic output capacitors. Soft-start is controlled with an external capacitor, which determines the input current ramp rate during start-up.The 8-lead MS8E package and high switching frequency ensure a low profile overall solution less than 1.1mm high.ApplicationsTFT-LCD Bias SuppliesGPS ReceiversDSL ModemsLocal Power Supply