Analog Devices Inc./Maxim Integrated

The LTC1955 provides all necessary supervisory and power control functions for two smart cards, two S.A.M. cards or a combination of S.A.M. and smart cards. It provides a charge pump for battery-powered applications as well as all necessary level shifting circuitry.The card voltages can be independently set to 1.8V, 3V or 5V. Both card interfaces include a card detection channel with automatic debounce circuitry. To reduce wiring costs, the LTC1955 interfaces to a microcontroller via a simple 4-wire serial interface. Multiple devices may be connected in daisychain fashion so that the number of wires to the card socket board is independent of the number of sockets. Status data is returned over the same interface.Extensive security features ensure proper deactivation sequencing in the event of a supply fault or a smart card electrical fault. The smart card pins can withstand greater than 10kV ESD in-situ with no additional components.The LTC1955 is available in a low profile (0.75mm) 5mm × 5mm QFN package.ApplicationsHandheld Payment TerminalsPay TelephonesATM MachinesPOS TerminalsComputer KeyboardsMultiple S.A.M. Sockets

The LTC1960 is a highly integrated battery charger and selector intended for portable products using dual smart batteries. A serial SPI interface allows an external microcontroller to control and monitor status of both batteries.A proprietary PowerPath architecture supports simultaneous charging or discharging of both batteries. Typical battery run times are extended by 10%, while charging times are reduced by up to 50%. The LTC1960 automatically switches between power sources in less than 10µs to prevent power interruption upon battery or wall adapter removal.The synchronous buck battery charger delivers 95% efficiency with only 0.5V dropout voltage, and prevents audible noise in all operating modes. Patented input current limiting with 5% accuracy charges batteries in the shortest possible time without overloading the wall adapter.The LTC1960’s 5mm × 7mm 38-pin QFN and 36-pin narrow SSOP packages allow implementation of a complete SBS-compliant dual battery system while consuming minimum PCB area.ApplicationsPortable ComputersPortable Instruments

The LTC1966 is a true RMS-to-DC converter that utilizes an innovative patented ∆Σ computational technique. The internal delta sigma circuitry of the LTC1966 makes it simpler to use, more accurate, lower power and dramatically more flexible than conventional log antilog RMS-to-DC converters.The LTC1966 accepts single-ended or differential input signals (for EMI/RFI rejection) and supports crest factors up to 4. Common mode input range is rail-to-rail. Differential input range is 1VPEAK, and offers unprecedented linearity. Unlike previously available RMS-to-DC converters, the superior linearity of the LTC1966 allows hassle free system calibration at any input voltage.The LTC1966 also has a rail-to-rail output with a separate output reference pin providing flexible level shifting. The LTC1966 operates on a single power supply from 2.7V to 5.5V or dual supplies up to ±5.5V. A low power shutdown mode reduces supply current to 0.5μA.The LTC1966 is insensitive to PC board soldering and stresses, as well as operating temperature. The LTC1966 is packaged in the space saving MSOP package which is ideal for portable applications.ApplicationsTrue RMS Digital Multimeters and Panel MetersTrue RMS AC + DC Measurements

The LTC1981/LTC1982 are low-power, self-contained N-channel MOSFET drivers. An internal voltage tripler allows gates to be driven without the use of any external components. Internal regulation circuitry allows quiescent current to drop to 10µA per driver (20µA for LTC1981) once the gates are charged.Low quiescent current and low shutdown current (under 1µA) make these parts ideal for battery and other power constrained systems. The wide input voltage range accommodates a variety of battery/input configurations.Gate drive is internally clamped to 7.5V providing protection to the external MOSFET gate. The MOSFETs can be driven in either high side or low side mode.The LTC1981 single driver version also includes a gate drive ready pin and twice the drive current capacity of the dual driver LTC1982.The LTC1981 is available in a 5-pin SOT-23. The LTC1982 is available in a 6-pin SOT-23.ApplicationsCellular TelephonesPortable POS TerminalHandheld Battery Powered Equipment

The LTC1981/LTC1982 are low-power, self-contained N-channel MOSFET drivers. An internal voltage tripler allows gates to be driven without the use of any external components. Internal regulation circuitry allows quiescent current to drop to 10µA per driver (20µA for LTC1981) once the gates are charged.Low quiescent current and low shutdown current (under 1µA) make these parts ideal for battery and other power constrained systems. The wide input voltage range accommodates a variety of battery/input configurations.Gate drive is internally clamped to 7.5V providing protection to the external MOSFET gate. The MOSFETs can be driven in either high side or low side mode.The LTC1981 single driver version also includes a gate drive ready pin and twice the drive current capacity of the dual driver LTC1982.The LTC1981 is available in a 5-pin SOT-23. The LTC1982 is available in a 6-pin SOT-23.ApplicationsCellular TelephonesPortable POS TerminalHandheld Battery Powered Equipment

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 –VINsupply) 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 theSHDNpin.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.Applications–3V Generation in Single-Supply SystemsPortable EquipmentLCD Bias SuppliesGaAs FET Bias Supplies

The LTC1985-1.8 is a triple supply monitor intended for systems with multiple supply voltages. The reset output remains low until all three supplies have been in compliance for 200ms. Tight 1.5% accuracy specifications and glitch immunity ensure reliable reset operation without false triggering.TheRSToutput is guaranteed to be in the correct state for VCC18or VCC3down to 1V. The LTC1985 may also be configured to monitor any one or two VCCinputs instead of three, depending on system requirements.Very low (10µA typical) supply current makes the LTC1985 ideal for power conscious systems.The LTC1985 is available in a 5-lead SOT-23 package.ApplicationsDesktop ComputersNotebook ComputersIntelligent InstrumentsPortable Battery-Powered EquipmentNetwork Servers