Analog Devices

The LT1175 is a negative micropower low dropout regulator. It features 45μA quiescent current, dropping to 10μA in shutdown. A new reference amplifier topology gives precision DC characteristics along with the ability to maintain good loop stability with an extremely wide range of output capacitors. Very low dropout voltage and high efficiency are obtained with a unique power transistor anti-saturation design. Adjustable and fixed 5V versions are available.Several new features make the LT1175 very user-friendly. TheSHDNpin can interface directly to either positive or negative logic levels. Current limit is user-selectable at 200mA, 400mA, 600mA and 800mA. The output can be forced to reverse voltage without damage or latch-up. Unlike some earlier designs, the increase in quiescent current during a dropout condition is actively limited.The LT1175 has complete blowout protection with current limiting, power limiting and thermal shutdown. Special attention was given to the problem of high temperature operation with micropower operating currents, preventing output voltage rise under no-load conditions. The LT1175 is available in 8-pin PDIP and SO packages, 3-lead SOT-223 as well as 5-pin surface mount DD and through-hole TO-220 packages. The 8-pin SO package is specially constructed for low thermal resistance.ApplicationsAnalog SystemsModemsInstrumentationA/D and D/A ConvertersInterface DriversBattery-Powered Systems

The LT1176 is a 1A monolithic bipolar switching regulator which requires only a few external parts for normal operation. The power switch, all oscillator and control circuitry and all current limit components are included on the chip. The topology is a classic positive buck configuration but several design innovations allows this device to be used as a positive-to-negative converter, a negative boost converter, and as a flyback converter. The switch output is specified to swing below ground.The LT1176 uses a true analog multiplier in the feedback loop. This makes the device respond nearly instantaneously to input voltage fluctuations and makes loop gain independent of input voltage. As a result, dynamic behavior of the regulator is significantly improved over previous designs.On-chip pulse by pulse current limiting makes the LT1176 nearly bust proof for output overloads or shorts. The input voltage range as a buck converter is 8V to 35V, but a self boot feature allows input voltages as low as 5V in the inverting and boost configurations.The LT1176 is available in a low cost 8-lead DIP package with frequency preset at 100kHz and current limit at 1.7A. An adjustable output is offered as well as a preset 5V version. For further design details and application help, see the LT1074/LT1076 data sheet and Application Note 44.ApplicationsBuck Converter with Output Voltage Range of 2.5V to 30VPositive-to-Negative ConverterNegative Boost ConverterMultiple Output Buck Converter

The LT1178 is a micropower dual op amp in the standard 8-pin configuration; the LT1179 is a micropower quad op amp offered in the standard 14-pin packages. Both devices are optimized for single supply operation at 5V. Specifications are also provided at ±15V supplies.The extremely low supply current is combined with true precision specifications: offset voltage is 30µV, offset current is 50pA. Both offset parameters have low drift with temperature. The 1.5pAP-Pcurrent noise and picoampere offset current permit the use of megaohm level source resistors without introducing serious errors. Voltage noise, at 0.9µVP-P, is remarkably low considering the low supply current.Both the LT1178 and LT1179 can be operated from a single supply (as low as one lithium cell or two NiCd batteries). The input range goes below ground. The all-NPN output stage swings to within a few millivolts of ground while sinking current—no power consuming pull down resistors are needed.For applications where three times higher supply current is acceptable, the micropower LT1077 single, LT1078 dual and LT1079 quad are recommended. The LT1077/78/79 have significantly higher bandwidth, slew rate, lower voltage noise and better output drive capability.ApplicationsBattery or Solar Powered SystemsPortable InstrumentationRemote Sensor AmplifierSatellite CircuitryMicropower Sample-and-HoldThermocouple AmplifierMicropower Filters

The LT1178 is a micropower dual op amp in the standard 8-pin configuration; the LT1179 is a micropower quad op amp offered in the standard 14-pin packages. Both devices are optimized for single supply operation at 5V. Specifications are also provided at ±15V supplies.The extremely low supply current is combined with true precision specifications: offset voltage is 30µV, offset current is 50pA. Both offset parameters have low drift with temperature. The 1.5pAP-Pcurrent noise and picoampere offset current permit the use of megaohm level source resistors without introducing serious errors. Voltage noise, at 0.9µVP-P, is remarkably low considering the low supply current.Both the LT1178 and LT1179 can be operated from a single supply (as low as one lithium cell or two NiCd batteries). The input range goes below ground. The all-NPN output stage swings to within a few millivolts of ground while sinking current—no power consuming pull down resistors are needed.For applications where three times higher supply current is acceptable, the micropower LT1077 single, LT1078 dual and LT1079 quad are recommended. The LT1077/78/79 have significantly higher bandwidth, slew rate, lower voltage noise and better output drive capability.ApplicationsBattery or Solar Powered SystemsPortable InstrumentationRemote Sensor AmplifierSatellite CircuitryMicropower Sample-and-HoldThermocouple AmplifierMicropower Filters

The LT1180A/LT1181A are dual RS232 driver/receiver pairs with integral charge pump to generate RS232 voltage levels from a single 5V supply. These circuits feature rugged bipolar design to provide operating fault tolerance and ESD protection unmatched by competing CMOS designs. Using only 0.1µF external capacitors, these circuits consume only 40mW of power, and can operate to 120k baud even while driving heavy capacitive loads. New ESD structures on the chip allow the LT1180A/LT1181A to survive multiple ±10kV strikes, eliminating the need for costly TransZorbs®on the RS232 line pins. The LT1180A/LT1181A are fully compliant with EIA RS232 standards. Driver outputs are protected from overload, and can be shorted to ground or up to ±30V without damage. During shutdown or power-off conditions, driver and receiver outputs are in a high impedance state, allowing line sharing.The LT1181A is available in 16-pin DIP and SO packages. The LT1180A is supplied in 18-pin DIP and SO packages for applications which require shutdown.ApplicationsPortable ComputersBattery-Powered SystemsPower Supply GeneratorTerminalsModems

The LT1180A/LT1181A are dual RS232 driver/receiver pairs with integral charge pump to generate RS232 voltage levels from a single 5V supply. These circuits feature rugged bipolar design to provide operating fault tolerance and ESD protection unmatched by competing CMOS designs. Using only 0.1µF external capacitors, these circuits consume only 40mW of power, and can operate to 120k baud even while driving heavy capacitive loads. New ESD structures on the chip allow the LT1180A/LT1181A to survive multiple ±10kV strikes, eliminating the need for costly TransZorbs®on the RS232 line pins. The LT1180A/LT1181A are fully compliant with EIA RS232 standards. Driver outputs are protected from overload, and can be shorted to ground or up to ±30V without damage. During shutdown or power-off conditions, driver and receiver outputs are in a high impedance state, allowing line sharing.The LT1181A is available in 16-pin DIP and SO packages. The LT1180A is supplied in 18-pin DIP and SO packages for applications which require shutdown.ApplicationsPortable ComputersBattery-Powered SystemsPower Supply GeneratorTerminalsModems

The LT1182/LT1183 are dual current mode switching regulators that provide the control function for Cold Cathode Fluorescent Lighting (CCFL) and Liquid Crystal Display (LCD) Contrast. The LT1184/LT1184F provide only the CCFL function. The ICs include high current, high efficiency switches, an oscillator, a reference, output drive logic, control blocks and protection circuitry. The LT1182 permits positive or negative voltage LCD contrast operation. The LT1183 permits unipolar contrast operation and pins out an internal reference. The LT1182/LT1183 support grounded and floating lamp configurations. The LT1184F supports grounded and floating lamp configurations. The LT1184 supports only grounded lamp configurations.ApplicationsNotebook and Palmtop ComputersPortable InstrumentsAutomotive DisplaysRetail Terminals

The LT1182/LT1183 are dual current mode switching regulators that provide the control function for Cold Cathode Fluorescent Lighting (CCFL) and Liquid Crystal Display (LCD) Contrast. The LT1184/LT1184F provide only the CCFL function. The ICs include high current, high efficiency switches, an oscillator, a reference, output drive logic, control blocks and protection circuitry. The LT1182 permits positive or negative voltage LCD contrast operation. The LT1183 permits unipolar contrast operation and pins out an internal reference. The LT1182/LT1183 support grounded and floating lamp configurations. The LT1184F supports grounded and floating lamp configurations. The LT1184 supports only grounded lamp configurations.ApplicationsNotebook and Palmtop ComputersPortable InstrumentsAutomotive DisplaysRetail Terminals

The LT1182/LT1183 are dual current mode switching regulators that provide the control function for Cold Cathode Fluorescent Lighting (CCFL) and Liquid Crystal Display (LCD) Contrast. The LT1184/LT1184F provide only the CCFL function. The ICs include high current, high efficiency switches, an oscillator, a reference, output drive logic, control blocks and protection circuitry. The LT1182 permits positive or negative voltage LCD contrast operation. The LT1183 permits unipolar contrast operation and pins out an internal reference. The LT1182/LT1183 support grounded and floating lamp configurations. The LT1184F supports grounded and floating lamp configurations. The LT1184 supports only grounded lamp configurations.ApplicationsNotebook and Palmtop ComputersPortable InstrumentsAutomotive DisplaysRetail Terminals

The LT1185 is a 3A low dropout regulator with adjustable current limit and remote sense capability. It can be used as a positive output regulator with floating input or as a standard negative regulator with grounded input. The output voltage range is 2.5V to 25V, with ±1% accuracy on the internal reference voltage.The LT1185 uses a saturation-limited NPN transistor as the pass element. This device gives the linear dropout characteristics of a FET pass element with significantly less die area. High efficiency is maintained by using special anti-saturation circuitry that adjusts base drive to track load current. The "on resistance" is typically 0.25Ω.Accurate current limit is programmed with a single 1/8W external resistor, with a range of zero to three amperes. A second, fixed internal limit circuit prevents destructive currents if the programming current is accidentally over-ranged. Shutdown of the regulator output is guaranteed when the program current is less than 1µA, allowing external logic control of output voltage.The LT1185 has all the protection features of our previous regulators, including power limiting and thermal shutdown.