Analog Devices Inc./Maxim Integrated

The LTC1487 is an ultra-low power differential line transceiver designed with high impedance inputs allowing up to 256 transceivers to share a single bus. It meets the requirements of RS485 and RS422. The LTC1487 features output drivers with controlled slew rate, decreasing the EMI radiated from the RS485 lines, and improving signal fidelity with misterminated lines. The CMOS design offers significant power savings without sacrificing ruggedness against overload or ESD damage. Typical quiescent current is only 80µA while operating and 1µA in shutdown.The driver and receiver feature three-state outputs, with the driver outputs maintaining high impedance over the entire common-mode range. Excessive power dissipation caused by bus contention or faults is prevented by a thermal shutdown circuit which forces the driver outputs into a high impedance state. The receiver has a fail-safe feature which guarantees a high output state when the iputs are left open. I/O pins are protected against multiple ESD strikes of over ±10kV using the Human Body Model. The LTC1487 is fully specified over the commercial temperature range and is available in 8-pin DIP and SO packages.ApplicationsBattery-Powered RS485/RS422 ApplicationsLow Power RS485/RS422 TransceiverLevel Translator

The LTC1503-1.8/LTC1503-2 are switched capacitor step-down DC/DC converters that produce a regulated output from a 2.4V to 6V input. The parts use switched capacitor fractional conversion to achieve high efficiency over the entire input range. No inductors are required. Internal circuitry controls the step-down conversion ratio to optimize efficiency as the input voltage and load conditions vary. Typical efficiency is 25% higher than that of a low dropout (LDO) linear regulator.Regulation is achieved by sensing the output voltage and enabling the internal switching network as needed to maintain a fixed output voltage. This method of regulation enables the parts to achieve high efficiency at extremely light loads. Low operating current (25µA with no load, 5µA in shutdown) and low external parts count (two 1µF flying capacitors and two 10µF bypass capacitors) make the LTC1503-1.8/LTC1503-2 ideally suited for space constrained battery-powered applications. The parts are fully short-circuit and over temperature protected.The LTC1503-1.8/LTC1503-2 are available in 8-pin MSOP and SO packages.ApplicationsCellular PhonesHandheld ComputersSmart Card ReadersLow Power DSP SuppliesPortable Electronic EquipmentHandheld Medical Instruments

The LTC1504 is a self-contained, high efficiency synchronous buck switching regulator. It includes a pair of on-chip 1.5Ω power switches, enabling it to supply up to 500mA of load current. Efficiency peaks at 92%, minimizing heat and wasted power. The synchronous buck architecture allows the output to source or sink current as required to keep the output voltage in regulation.The LTC1504 is available in adjustable and fixed 3.3V output versions. An adjustable current limit circuit provides protection from overloads. The internal 1% reference combined with a sophisticated voltage feedback loop provides optimum output voltage accuracy and fast load transient response. The LTC1504 is specified to operate with input voltages between 4V and 10V. Contact the LTC factory for guaranteed specifications at 2.7V supply.The LTC1504 is available in a plastic SO-8 package.ApplicationsSmall Portable Digital SystemsActive TerminationAuxiliary Output Voltage SuppliesMinimum Part Count/Size Switchers

The LTC1504A is a self-contained, high efficiency synchronous buck switching regulator. It includes a pair of on-chip 1.3Ω power switches, enabling it to supply up to 500mA of load current. Efficiency peaks at 92%, minimizing heat and wasted power. The synchronous buck architecture allows the output to source or sink current as required to keep the output voltage in regulation. 100% duty cycle operation minimizes dropout voltage.The LTC1504A is available in adjustable and fixed 3.3V output versions. An adjustable current limit circuit provides protection from overloads. The internal 1% reference combined with a sophisticated voltage feedback loop provides optimum output voltage accuracy and fast load transient response. The LTC1504A is specified to operate with input voltages between 4V and 10V. Contact the LTC factory for guaranteed specifications at 2.7V supply.The LTC1504A is a pin-compatible, functional upgrade to the LTC1504.The LTC1504A is available in a plastic SO-8 package.ApplicationsSmall Portable Digital SystemsActive TerminationAuxiliary Output Voltage SuppliesMinimum Part Count/Size Switchers

The LTC1514-3.3/LTC1514-5 are micropower switched capacitor DC/DC converters that produce a regulated output voltage by either stepping up or stepping down the input voltage. Output voltage is fixed at either 3.3V (LTC1514-3.3) or 5V (LTC1514-5) by an internal resistor divider.A unique architecture allows the parts to accommodate a wide input voltage range (2V to 10V) while maintaining+4% regulation. Additional circuitry prevents excessive inrush current and output voltage ripple when large VINto VOUTdifferentials are present.An internal uncommitted comparator is kept active in shutdown. The comparator has an open-drain output for flexible interfacing.The parts are short-circuit and overtemperature protected. Battery life is maximized by very low operating currents (ICC= 60µA typ, 10µA in shutdown). Both parts are available in an SO-8 package.ApplicationsBattery Operated EquipmentSmart Card ReadersLocal Power SuppliesHandheld InstrumentsBattery Backup Supplies

The LTC1517-5 is a micropower charge pump DC/DC converter that produces a regulated 5V output. The input voltage range is 2.7V to 5V. Extremely low operating current (typically 6µA with no load) and low external parts count (one 0.1µF flying capacitor and two small bypass capacitors at VINand VOUT) make the part ideally suited for small, light load battery-powered applications. The total printed circuit board area of the application circuit shown below is only 0.045in2.The part operates as a Burst Mode™switched-capacitor voltage doubler to produce a regulated output. The part has thermal shutdown capability and can survive a continuous short circuit from VOUTto GND. The device is available in a 5-pin SOT-23 package.ApplicationsCellular TelephonesBattery-Operated EquipmentLocal Power SuppliesHandheld InstrumentsPCMCIA Supplies