Analog Devices

The LTC1235 provides complete power supply monitoring and battery control functions for microprocessor reset, battery backup, RAM write protection, power failure warning and watchdog timing. The LTC1235 has all the LTC695 features plus conditional battery backup and external reset control. When an out-of-tolerance power supply condition occurs, the reset outputs are forced to active states and the Chip Enable output write-protects external memory. TheRESEToutput is guaranteed to remain logic low with VCCas low as 1V. External reset control is provided by a debounced push-button reset input.The LTC1235 powers the active CMOS RAMs with a charge pumped NMOS power switch to achieve low dropout and low supply current. When primary power is lost, auxiliary power, connected to the battery input pin, provides backup power to the RAMs. The LTC1235 can be programmed by a P signal to either back up the RAMs or not. This extends the battery life in situations where RAM data need not always be saved when power goes down.For an early warning of impending power failure, the LTC1235 provides an internal comparator with a user-defined threshold. An internal watchdog timer is also available, which forces the reset pins to active states when the watchdog input is not toggled prior to the time-out period.ApplicationsCritical µP Power MonitoringIntelligent InstrumentsBattery-Powered Computers and ControllersAutomotive Systems

The LTC1250 is a high performance, very low noise zero-drift operational amplifier. The LTC1250's combination of low front-end noise and DC precision makes it ideal for use with low impedance bridge transducers. The LTC1250 features typical input noise of 0.75µVP-Pfrom 0.1Hz to 10Hz, and 0.2µVP-Pfrom 0.1Hz to 1Hz. The LTC1250 has DC to 1Hz noise of 0.35µVP-P, surpassing that of low noise bipolar parts including the OP-07, OP-77, and LT1012. The LTC1250 uses the industry-standard single op amp pinout, and requires no external components or nulling signals, allowing it to be a plug-in replacement for bipolar op amps.The LTC1250 incorporates an improved output stage capable of driving 4.3V into a 1k load with a single 5V supply; it will swing ±4.9V into 5k with ±5V supplies. The input common mode range includes ground with single power supply voltages above 12V. Supply current is 3mA with a ±5V supply, and overload recovery times from positive and negative saturation are 0.5ms and 1.5ms, respectively. The internal nulling clock is set at 5kHz for optimum low frequency noise and offset drift; no external connections are necessary.The LTC1250 is available in a standard 8-pin plastic DIP and 8-pin SO packages.Protected by U.S. Patents including 4933642.ApplicationsElectronic ScalesStrain Gauge AmplifiersThermocouple AmplifiersHigh Resolution Data AcquisitionLow Noise TransducersInstrumentation Amplifiers

The LTC1255 dual high-side driver allows using low cost N-channel FETs for high-side industrial and automotive switching applications. An internal charge pump boosts the gate drive voltage above the positive rail, fully enhancing an N-channel MOS switch with no external components. Low power operation, with 12µA standby current, allows use in virtually all systems with maximum efficiency.Included on-chip is independent overcurrent sensing to provide automatic shutdown in case of short circuits. A time delay can be added to the current sense to prevent false triggering on high in-rush current loads.The LTC1255 operates from 9V to 24V supplies and is well suited for industrial and automotive applications.The LTC1255 is available in both an 8-pin DIP and an 8-pin SOIC.ApplicationsSolenoid DriversDC Motor DriversStepper Motor DriversLamp Drivers/DimmersRelay DriversLow Frequency H-BridgeP-Channel Switch Replacement

The LTC®1257 is a complete single supply, 12-bit voltage output D/A converter (DAC) in an SO-8 package. The LTC1257 includes an output buffer amplifier, 2.048V voltage reference and an easy to use 3-wire cascadable serial interface. An external reference can be used to override the internal reference and extend the output voltage range to 12V. The power supply current is a low 350µA when operating from a 5V supply, making the LTC1257 ideal for battery-powered applications. The space-saving 8-pin SO package and operation with no external components provide the smallest 12-bit D/A system available.ApplicationsDigital Offset/Gain AdjustmentIndustrial Process ControlAutomatic Test Equipment

The LTC1261L is a switched-capacitor voltage inverter designed to provide a regulated negative voltage from a single positive supply. The LTC1261L operates from a single 2.7V to 5.25V supply and provides an adjustable output voltage from -1.23V to ±5V. The LTC1261L-4/LTC1261L-4.5 needs a single 4.5V to 5.25V supply and provides a fixed output voltage of -4V to -4.5V respectively. Three external capacitors are required: a 0.1µF flying capacitor and an input and output bypass capacitors. An optional compensation capacitor at ADJ (COMP) can be used to reduce the output voltage ripple.Each version of the LTC1261L will supply up to 20mA output current with guaranteed output regulation of ±3.5%. The LTC1261L includes an open-drain REG output that pulls low when the output is within 5% of the set value. Quiescent current is typically 650µA when operating and 5µA in shutdown.The LTC1261L is available in 8-pin MSOP and SO packages.ApplicationsGaAs FET Bias GeneratorsNegative Supply GeneratorsBattery-Powered SystemsSingle Supply Applications

The LTC1262 is a regulated 12V, 30mA output DC/DC converter. It is designed to provide the 12V ±5% output necessary to program byte-wide flash memories. The output will provide up to 30mA from input voltages as low as 4.75V without using any inductors. Only four external capacitors are required to complete an extremely small surface mountable circuit.The TTL compatible shutdown pin can be directly connected to a microprocessor and reduces the supply current to less than 0.5µA. The LTC1262 offers improved shutdown current performance and requires fewer external components than competing solutions.The LTC1262 is available in an 8-pin PDIP or SO-8 package.Applications12V Flash Memory Programming SuppliesCompact 12V Op Amp SuppliesBattery-Powered Systems

The LTC1263 is a regulated 12V, 60mA output DC/DC converter. It provides the 12V ±5% output necessary to program double byte-wide flash memories. The output provides 60mA from input voltages as low as 4.75V without using any inductors. Only four external capacitors are required to complete an extremely small, surface mountable circuit. The output can be momentarily shorted to ground without damaging the part.The active high TTL compatible Shutdown pin can be directly connected to a microprocessor. In the shutdown mode, the supply current typically drops to 0.5µA.The LTC1263 is available in an 8-pin SO package.Applications12V Flash Memory Programming SuppliesCompact 12V Op Amp SuppliesBattery-Powered Systems

The LTC1264-7 is a clock-tunable monolithic 8th order lowpass filter with linear passband phase and flat group delay. The amplitude response approximates a maximally flat passband and exhibits steeper roll-off than an equivalent 8th order Bessel filter. For instance, at twice the cutoff frequency, the filter attains 28dB attenuation (vs 12dB for Bessel), while at three times the cutoff frequency, the filter attains 55dB attenuation (vs 30dB for Bessel).The cutoff frequency of the LTC1264-7 is tuned via an external TTL or CMOS clock. The clock-to-cutoff frequency ratio of the LTC1264-7 can be set to 25:1 (pin 10 to V+) or 50:1 (pin 10 to V–). When the filter operates at clock-to-cutoff frequency ratio of 25:1, the input is double-sampled to lower the risk of aliasing.The LTC1264-7 is optimized for speed. Depending on the operating conditions, cutoff frequencies between 200kHz and 250kHz can be obtained. (Please refer to the Passband vs Clock Frequency graphs.)The LTC1264-7 is pin-compatible with the LTC1064-X series.ApplicationsData Communication FiltersTime Delay NetworksPhase Matched Filters

The LTC1265 is a monolithic step-down current mode DC/DC converter featuring Burst Mode™ operation at low output current. The LTC1265 incorporates a 0.3Ω switch (VIN=10V) allowing up to 1.2A of output current.Under no load condition, the converter draws only 160µA. In shutdown it typically draws a mere 5µA making this converter ideal for current sensitive applications. In dropout the internal P-channel MOSFET switch is turned on continuously maximizing the life of the battery source. The LTC1265 incorporates automatic power saving Burst Mode operation to reduce gate charge losses when the load currents drop below the level required for continuous operation.The inductor current is user-programmable via an external current sense resistor. Operation up to 700kHz permits the use of small surface mount inductors and capacitors.Applications5V to 3.3V ConversionDistributed Power SystemsStep-Down ConvertersInverting ConvertersMemory Backup SupplyPortable InstrumentsBattery-Powered EquipmentCellular Telephones