Analog Devices

The LTC1477/LTC1478 protected high side switches provide extremely low RDS(ON)switching with built-in protection against short-circuit and thermal overload conditions. A built-in charge pump generates gate drive higher than the supply voltage to fully enhance the internal NMOS switch. This switch has no parasitic body diode and therefore no current flows through the switch when it is turned off and the output is forced above the input supply voltage. (DMOS switches have parasitic body diodes that become forward biased under these conditions.)Two levels of protection are provided by the LTC1477/LTC1478. The first level of protection is short-circuit current limit which is set at 2A. The short-circuit current can be reduced to as low as 0.85A by disconnecting portions of the power device (see Applications Information). The second level of protection is provided by thermal overload protection which limits the die temperature to approximately 130°C.The LTC1477 single is available in 8-lead SO packaging. The LTC1478 dual is available in 16-lead SO packaging.ApplicationsNotebook Computer Power ManagementPower Supply/Load ProtectionSupply/Battery Switch-Over CircuitsCircuit Breaker FunctionPeripheral Power ProtectionReconstruction Filters

The LTC1479 is the "heart" of a total power management solution for single and dual battery notebook computers and other portable equipment. The LTC1479 directs power from up to two battery packs and a DC power source to the input of the main system switching regulator. It works in concert with related LTC power management products (e.g. LTC1435, LT1511, etc.) to create a total system solution; starting from the batteries and the DC power source, and ending at the input of each of the computer’s complex loads. A system-provided power management µP monitors and actively directs the LTC1479.The LTC1479 uses low loss N-channel MOSFET switches to direct power from three main sources. An adaptive current limiting scheme reduces capacitor and battery inrush current by controlling the gates of the MOSFET switches during transitions. The LTC1479 interfaces directly to the LT1510, LT1511 and LT1620/LTC1435 battery charging circuits.ApplicationsNotebook Computer Power ManagementPortable InstrumentsHandheld TerminalsPortable Medical EquipmentPortable Industrial Control Equipment

The LTC1480 is an ultralow power differential line transceiver which provides full RS485 compatibility while operating from a single 3.3V supply. It is designed for data transmission standard RS485 applications with extended common mode range (12V to -7V). It also meets the requirements of RS422 and features high speed operation up to 2.5Mb/s. The CMOS design offers significant power savings without sacrificing ruggedness against overload or ESD damage. Typical quiescent current is only 300µA 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 inputs are left open.The LTC1480 is fully specified over the commercial and extended industrial temperature range. The LTC1480 is available in 8-pin SO and DIP packages.ApplicationsBattery-Powered RS485/RS422 ApplicationsLow Power RS485/RS422 TransceiverLevel Translator

The LTC1481 is an ultralow power differential line transceiver designed for data transmission standard RS485 applications. It will also meet the requirements of RS422. The CMOS design offers significant power savings over its bipolar counterparts without sacrificing ruggedness against overload or ESD damage. Typical quiescent current is only 80µA while operating and less than 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 inputs are left open.The LTC1481 is fully specified over the commercial and extended industrial temperature range and is available in 8-pin PDIP and SO packages.ApplicationsBattery-Powered RS485/RS422 ApplicationsLow Power RS485/RS422 TransceiverLevel Translator

The LTC1482 is a low power RS485 compatible transceiver that offers an active low carrier detect output. The open-drain carrier detect pin allows several transceivers to share the same carrier detect line and can be used to detect the insertion or removal of a driven RS485/RS422 cable.Enhanced ESD protection allows the LTC1482 to withstand ±15kV (human body model), IEC-1000-4-2 level 4 (±8kV) contact and level 3 (±8kV) air discharge ESD without latchup or damage.The LTC1482 receiver stays alive at all times except in shutdown. The supply current is a maximum of 700µA and 900µA when the driver is disabled and enabled respectively. In shutdown, the quiescent current of the LTC1482 drops to a maximum of 20µA.When the driver is disabled or the LTC1482 is in shutdown, the driver outputs are three-stated and remain in a high impedance state over the RS485 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 LTC1482 is fully specified over the commercial and industrial temperature ranges and is available in 8-lead MSOP, PDIP and SO packages.ApplicationsBattery-Powered RS485/RS422 ApplicationsLow Power RS485/RS422 TransceiverLevel Translator

The LTC1483 is an ultra-low power differential line transceiver designed for data transmission standard RS485 applications with extended common-mode range (−7V to 12V). It will also meet the requirements of RS422. The LTC1483 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 over its bipolar counterparts without sacrificing ruggedness against overload or ESD damage. Typical quiescent current is only 80µA while operating and less than 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 inputs are left open. I/O pins are protected against multiple ESD strikes of over ±10kV.The LTC1483 is fully specified over the commercial and extended industrial temperature range and is available in 8-pin DIP and SO packages.ApplicationsBattery-Powered RS485/RS422 ApplicationsLow Power RS485/RS422 TransceiverLevel Translator

The LTC1484 is a low power RS485 compatible transceiver. In receiver mode, it offers a fail-safe feature which guarantees a high receiver output state when the inputs are left open, shorted together or terminated with no signal present. No external components are required to ensure the high receiver output state.Both driver and receiver feature three-state outputs with separate receiver and driver control pins. The driver outputs maintain high impedance over the entire common mode range when three-stated. Excessive power dissipation caused by bus contention or faults is prevented by a thermal shutdown circuit that forces the driver outputs into a high impedance state.Enhanced ESD protection allows the LTC1484 to withstand ±15kV (human body model), IEC-1000-4-2 level 4 (±8kV) contact and level 3 (±8kV) air discharge ESD without latchup or damage.The LTC1484 is fully specified over the commercial and industrial temperature ranges and is available in 8-lead MSOP, PDIP and SO packages.ApplicationsBattery-Powered RS485/RS422 ApplicationsLow Power RS485/RS422 TransceiverLevel Translator

The LTC1485 is a low power differential bus/line transceiver designed for multipoint data transmission standard RS485 applications with extended common-mode range (12V to –7V). It also meets the requirements of RS422.The CMOS with Schottky design offers significant power savings over its bipolar counterpart without sacrificing ruggedness against overload or ESD damage.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. I/O pins are protected against multiple ESD strikes of over ±10kV.The receiver has a fail-safe feature which guarantees a high output state when the inputs are left open.Both AC and DC specifications are guaranteed from –40°C to 85°C and 4.75V to 5.25V supply voltage range.ApplicationsLow Power RS485/RS422 TransceiverLevel Translator

The LTC1502-3.3 is a quadrupler charge pump DC/DC converter that produces a regulated 3.3V output from a single alkaline cell input. It requires only five small external capacitors—no inductors are required. Low supply current (40µA typical, 5µA in shutdown) and minimal external components make the LTC1502-3.3 ideal for space and power conscious single-cell applications. The total printed circuit board area of the circuit shown below is less than 0.125in2.Forcing the C1−/SHDNpin through an external resistive pull-down puts the part into shutdown mode. During shutdown, the internal oscillator is stopped and the load is disconnected from VIN. An internal pull-up current on the C1−/SHDNpin forces the part back into normal operation once the pull-down resistance is removed.The LTC1502-3.3 is short-circuit protected and survives an indefinite VOUTshort to ground. The LTC1502-3.3 is available in 8-pin MSOP and SO packages.ApplicationsPagersBattery Backup SuppliesPortable Electronic EquipmentHandheld Medical InstrumentsGlucose Meters

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