Analog Devices

The LTC1798/LTC1798-2.5/LTC1798-3/LTC1798-4.1/ LTC1798-5 are micropower bandgap references that combine high accuracy and low drift with very low supply current and small package size. The combination of ultralow quiescent current and low dropout voltage of only 200mV (max) makes them ideal for battery-powered equipment. The output voltage is set by an external resistor divider for the adjustable LTC1798.This series of references uses curvature compensation to obtain low temperature coefficient and trimmed thin-film resistors to achieve high output accuracy. These references can source up to 10mA and sink up to 2mA, making them ideal for precision regulator applications. They are stable without an output bypass capacitor, but are also stable with capacitance up to 1μF. This feature is important in critical applications where PC board space is a premium and fast settling is demanded.The LTC1798 series references provided power dissipation advantages over shunt references. In addition to supply current, shunt references must also idle the entire load current to operate.The LTC1798 series is available in the SO-8 package.ApplicationsBattery-Powered SystemsHandheld InstrumentsPrecision Power SuppliesA/D and D/A ConvertersAvailable in the SO-8 Package

The LTC1799 is a precision oscillator that is easy to use and occupies very little PC board space. The oscillator frequency is programmed by a single external resistor (RSET). The LTC1799 has been designed for high accuracy operation (≤1.5% frequency error) without the need for external trim components.The LTC1799 operates with a single 2.7V to 5.5V power supply and provides a rail-to-rail, 50% duty cycle square wave output. The CMOS output driver ensures fast rise/fall times and rail-to-rail switching. The frequency-setting resistor can vary from 3k to 1M to select a master oscillator frequency between 100kHz and 33MHz (5V supply). The three-state DIV input determines whether the master clock is divided by 1, 10 or 100 before driving the output, providing three frequency ranges spanning 1kHz to 33MHz (5V supply). The LTC1799 features a proprietary feedback loop that linearizes the relationship between RSETand frequency, eliminating the need for tables to calculate frequency.ApplicationsLow Cost Precision OscillatorSwitching Power Supply Clock ReferenceClocking Switched Capacitor FiltersFixed Crystal Oscillator ReplacementCeramic Oscillator Replacement

The LTC1821 is a parallel input 16-bit multiplying voltage output DAC that operates from analog supply voltages of ±5V up to ±15V. INL and DNL are accurate to 1LSB over the industrial temperature range in both unipolar 0V to 10V and bipolar ±10V modes. Precise 16-bit bipolar ±10V outputs are achieved with on-chip 4-quadrant multiplication resistors. The LTC1821 is available in a 36-lead SSOP package and is specified over the industrial temperature range.The device includes an internal deglitcher circuit that reduces the glitch impulse to less than 2nV•s (typ). The LTC1821 settles to 1LBS in 2µs with a full-scale 10V step. The combination of fast, precise settling and ultra low glitch make the LTC1821 ideal for precision industrial control applications.The asynchronousCLRpin resets the LTC1821 to zero scale and resets the LTC1821-1 to midscale.ApplicationsPrecision InstrumentationProcess Control and Industrial AutomationDirect Digital Waveform GenerationSoftware-Controlled Gain AdjustmentAutomatic Test Equipment

The LTC1840 is a fan controller with two 8-bit current output DACs, two tachometer interfaces, and four general purpose I/O (GPIO) pins. It operates from a single supply with a range of 2.7V to 5.75V. A current output DAC is used to control an external switching regulator, which controls the fan speed. A current output DAC and tachometer allow a controller to form a closed control loop on fan velocity. The GPIO pins can be used as digital inputs or open drain pull-down outputs.The part features a simple 2-wire I²C and SMBus compatible serial interface that allows communication between many devices. The interface includes a fault status register that reflects the state of the part and which can be polled to find the cause of a fault condition. Other operational characteristics of the part, such as DAC output currents, GPIO modes, and tachometer frequency, are also programmed through the serial interface. Two address pins provide nine possible device addresses.TheBLASTpin is provided to force the DAC output currents to program the maximum regulator output voltages through a single pin and gate the operation of the serial access timer.ApplicationsServersDesktop ComputersPower SuppliesCooling Systems

The LTC1841 is an ultralow power dual comparator featuring less than 5.7µA supply current over temperature, a 1.182V ±1% reference, programmable hysteresis and open-drain outputs that sink current. The reference output can drive a bypass capacitor of up to 0.01µF without oscillation.The LTC1841 operates from a single 2V to 11V supply or a dual ±1V to ±5.5V supply. The comparator inputs operate from the negative supply to within 1.3V of the positive supply. The comparator outputs can typically sink greater than 20mA. By eliminating the cross-conduction current that normally happens when the comparators change logic states, power supply glitches are eliminated.The LTC1841 are available in an SO-8 package.ApplicationsBattery-Powered System MonitoringThreshold DetectorsWindow ComparatorsOscillator Circuits

The LTC1842 is an ultralow power dual comparator with a built-in reference. The comparators feature less than 5.7µA supply current over temperature, a 1.182V ±1% reference, programmable hysteresis and open-drain outputs that sink current. The reference output can drive a bypass capacitor of up to 0.01µF without oscillation.The LTC1842 operate from a single 2.5V to 11V supply or a dual ±1.25V to ±5.5V supply. Hysteresis is easily programmed by using two resistors and the HYST pin. The comparator inputs operate from the negative supply to within 1.3V of the positive supply. The comparator outputs can typically sink greater than 20mA. By eliminating the cross-conduction current that normally happens when the comparators change logic states, power supply glitches are eliminated.The LTC1842 is available in an SO-8 package.ApplicationsBattery-Powered System MonitoringThreshold DetectorsWindow ComparatorsOscillator Circuits

The LTC1844 Series are low noise VLDO™(very low dropout) linear regulators designed for low power/portable applications. These regulators can operate from input voltages as low as 1.6V. Typical output noise is only 30µVRMSand typical dropout for the LTC1844-3.3 is just 90mV at the maximum load current of 150mA, reducing to 30mV at 50mA.The internal P-channel MOSFET pass transistor requires no base current, allowing the device to draw only 35µA during normal operation, independent of the dropout voltage and load current. The quiescent current falls to a negligible 10nA during shutdown.Other features include high output voltage accuracy, excellent transient response, stability with ultralow ESR ceramic capacitors as small as 1µF, reverse-battery and reverse-current protection, short-circuit and thermal overload protection and output current limiting.The LTC1844 regulators are available in a low profile (1mm) SOT-23 (ThinSOT™) package.ApplicationsPortable Instruments and Battery-Powered SystemsBluetooth/802.11 CardsCellular PhonesPDAs and Notebook Computers

The 10-bit LTC1850 and 12-bit LTC1851 are complete 8-channel data acquisition systems. They include a flexible 8-channel multiplexer, a 1.25Msps successive approximation analog-to-digital converter with sample-and-hold, an internal 2.5V reference and reference buffer amplifier, and a parallel output interface. The multiplexer can be configured for single-ended or differential inputs, two gain ranges and unipolar or bipolar operation.The ADCs have a scan mode that will repeatedly cycle through all 8 multiplexer channels and can also be programmed with a sequence of up to 16 addresses and configurations that can be scanned in succession. The sequence memory can also be read back. The reference and buffer amplifier provide pin strappable ranges of 4.096V, 2.5V and 2.048V. The parallel output includes the 10-bit or 12-bit conversion result plus the 4-bit multiplexer address. The digital outputs are powered from a separate supply allowing for easy interface to 3V digital logic. Typical power consumption is 40mW at 1.25Msps from a single 5V supply.ApplicationsHigh Speed Data AcquisitionTest and MeasurementImaging SystemsTelecommunicationsIndustrial Process ControlSpectrum Analysis

The 10-bit LTC1850 and 12-bit LTC1851 are complete 8-channel data acquisition systems. They include a flexible 8-channel multiplexer, a 1.25Msps successive approximation analog-to-digital converter with sample-and-hold, an internal 2.5V reference and reference buffer amplifier, and a parallel output interface. The multiplexer can be configured for single-ended or differential inputs, two gain ranges and unipolar or bipolar operation.The ADCs have a scan mode that will repeatedly cycle through all 8 multiplexer channels and can also be programmed with a sequence of up to 16 addresses and configurations that can be scanned in succession. The sequence memory can also be read back. The reference and buffer amplifier provide pin strappable ranges of 4.096V, 2.5V and 2.048V. The parallel output includes the 10-bit or 12-bit conversion result plus the 4-bit multiplexer address. The digital outputs are powered from a separate supply allowing for easy interface to 3V digital logic. Typical power consumption is 40mW at 1.25Msps from a single 5V supply.ApplicationsHigh Speed Data AcquisitionTest and MeasurementImaging SystemsTelecommunicationsIndustrial Process ControlSpectrum Analysis

The 10-bit LTC1852 and 12-bit LTC1853 are complete 8-channel data acquisition systems. They include a flexible 8-channel multiplexer, a 400ksps successive approximation analog-to-digital converter, an internal reference and a parallel output interface. The multiplexer can be configured for single-ended or differential inputs, two gain ranges and unipolar or bipolar operation. The ADCs have a scan mode that will repeatedly cycle through all 8 multiplexer channels and can also be programmed to sequence through up to 16 addresses and configurations. The sequence can also be read back from internal memory.The reference and buffer amplifier provide pin strappable ranges of 4.096V, 2.5V and 2.048V. The parallel output includes the 10-bit or 12-bit conversion result plus the 4-bit multiplexer address. The digital outputs are powered from a separate supply allowing for easy interface to 3V digital logic. Typical power consumption is 10mW at 400ksps from a single 5V supply and 3mW at 250ksps from a single 3V supply.ApplicationsHigh Speed Data AcquisitionTest and MeasurementImaging SystemsTelecommunicationsIndustrial Process ControlSpectrum Analysis