Analog Devices

The LT1920 is a low power, precision instrumentation amplifier that requires only one external resistor to set gains of 1 to 10,000. The low voltage noise of 7.5nV/√Hz(at 1kHz) is not compromised by low power dissipation (0.9mA typical for ±2.3V to ±15V supplies).The high accuracy of 30ppm maximum nonlinearity and 0.3% max gain error (G = 10) is not degraded even for load resistors as low as 2k (previous monolithic instrumentation amps used 10k for their nonlinearity specifications). The LT1920 is laser trimmed for very low input offset voltage (125µV max), drift (1µV/°C), high CMRR (75dB, G = 1) and PSRR (80dB, G = 1). Low input bias currents of 2nA max are achieved with the use of superbeta processing. The output can handle capacitive loads up to 1000pF in any gain configuration while the inputs are ESD protected up to 13kV (human body). The LT1920 with two external 5k resistors passes the IEC 1000-4-2 level 4 specification.The LT1920, offered in 8-pin PDIP and SO packages, is a pin for pin and spec for spec improved replacement for the AD620. The LT1920 is the most cost effective solution for precision instrumentation amplifier applications. For even better guaranteed performance, see the LT1167.ApplicationsBridge AmplifiersStrain Gauge AmplifiersThermocouple AmplifiersDifferential to Single-Ended ConvertersMedical Instrumentation

The LT1930 and LT1930A are the industry's highest power SOT-23 switching regulators. Both include an internal 1A, 36V switch allowing high current outputs to be generated in a small footprint. The LT1930 switches at 1.2MHz, allowing the use of tiny, low cost and low height capacitors and inductors. The faster LT1930A switches at 2.2MHz, enabling further reductions in inductor size. Complete regulator solutions approaching one tenth of a square inch in area are achievable with these devices. Multiple output power supplies can now use a separate regulator for each output voltage, replacing cumbersome quasi-regulated approaches using a single regulator and custom transformers.A constant frequency internally compensated current mode PWM architecture results in low, predictable output noise that is easy to filter. Low ESR ceramic capacitors can be used at the output, further reducing noise to the millivolt level. The high voltage switch on the LT1930/LT1930A is rated at 36V, making the device ideal for boost converters up to 34V as well as for single-ended primary inductance converter (SEPIC) and flyback designs. The LT1930 can generate 5V at up to 480mA from a 3.3V supply or 5V at 300mA from four alkaline cells in a SEPIC design.The LT1930/LT1930A are available in the 5-lead ThinSOT package.ApplicationsTFT-LCD Bias SupplyDigital CamerasCordless PhonesBattery BackupMedical Diagnostic EquipmentLocal 5V or 12V SupplyExternal ModemsPC CardsxDSL Power Supply

The LT1933 is a current mode PWM step-down DC/DC converter with an internal 0.75A power switch, packaged in a tiny 6-lead SOT-23. The wide input range of 3.6V to 36V makes the LT1933 suitable for regulating power from a wide variety of sources, including unregulated wall transformers, 24V industrial supplies and automotive batteries. Its high operating frequency allows the use of tiny, low cost inductors and ceramic capacitors, resulting in low, predictable output ripple.Cycle-by-cycle current limit provides protection against shorted outputs, and soft-start eliminates input current surge during start up. The low current (<2µA) shutdown provides output disconnect, enabling easy power management in battery-powered systems.ApplicationsAutomotive Battery RegulationIndustrial Control SuppliesWall Transformer RegulationDistributed Supply RegulationBattery-Powered Equipment

The LT1934 is a micropower step-down DC/DC converter with internal 400mA power switch, packaged in a low profile (1mm) ThinSOT. With its wide input range of 3.2V to 34V, the LT1934 can regulate a wide variety of power sources, from 4-cell alkaline batteries and 5V logic rails to unregulated wall transformers and lead-acid batteries. Quiescent current is just 12µA and a zero current shutdown mode disconnects the load from the input source, simplifying power management in battery-powered systems. Burst Mode®operation and the low drop internal power switch result in high efficiency over a broad range of load current.The LT1934 provides up to 300mA of output current. The LT1934-1 has a lower current limit, allowing optimum choice of external components when the required output current is less than 60mA. Fast current limiting protects the LT1934 and external components against shorted outputs, even at 34V input.ApplicationsWall Transformer RegulationAutomotive Battery RegulationStandby Power for Portable ProductsDistributed Supply RegulationIndustrial Control Supplies

The LT1936 is a current mode PWM step-down DC/DC converter with an internal 1.9A power switch, packaged in a tiny, thermally enhanced 8-lead MSOP. The wide input range of 3.6V to 36V makes the LT1936 suitable for regulating power from a wide variety of sources, including automotive batteries, 24V industrial supplies and unregulated wall adapters. Its high operating frequency allows the use of small, low cost inductors and ceramic capacitors, resulting in low, predictable output ripple.Cycle-by-cycle current limit, frequency foldback and thermal shutdown provide protection against shorted outputs, and soft-start eliminates input current surge during startup. Transient response can be optimized by using external compensation components, or board space can be minimized by using internal compensation. The low current (<2µA) shutdown mode enables easy power management in battery-powered systems.ApplicationsAutomotive Battery RegulationIndustrial Control SuppliesUnregulated Wall Adapters

The LT1937 is a step-up DC/DC converter specifically designed to drive white LEDs with a constant current. The device can drive two, three or four LEDs in series from a Li-Ion cell. Series connection of the LEDs provides identical LED currents resulting in uniform brightness and eliminating the need for ballast resistors. The LT1937 switches at 1.2MHz, allowing the use of tiny external components. The output capacitor can be as small as 0.22µF, saving space and cost versus alternative solutions. A low 95mV feedback voltage minimizes power loss in the current setting resistor for better efficiency.The LT1937 is available in low profile SC70 and ThinSOT packages.ApplicationsCellular PhonesPDAs, Handheld ComputersDigital CamerasMP3 PlayersGPS Receivers

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

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

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