LINEAR Manuals

The LT1078/LT1079 are Texas Instruments' micropower dual- and quad-channel single-supply precision op amps, with a maximum supply current of 50µA and a low voltage noise of 0.6µVP-P, 0.1Hz to 10Hz.

4- and 8-Channel, 3V Micropower Sampling 12-Bit Serial I/O A/D Converters

The LT ®1494/LT1495/LT1496 are the lowest power (IS ≤ 1.5µA) op amps with precision specifications. The extremely low supply current is combined with excellent amplifier specifications: input offset voltage is 375µV maximum with a typical drift of only 0.4µV/°C, input offset current is 100pA maximum. A minimum open-loop gain (AVOL) of 100V/mV ensures that gain errors are small. The device characteristics change little over the supply range of 2.2V to ±15V. Supply rejection is 90dB and the common mode rejection ratio is 90dB. Operation is specified for 3V, 5V and ±15V supplies. Reverse battery protection (–18V␣min) and inputs that operate above the positive supply make the LT1494/LT1495/LT1496 easy to use in harsh environments. The low bias currents and offset current of the amplifier permit the use of megohm level source resistors without introducing significant errors.

The LT1680 is a high power, current mode switching power supply controller optimized for boost topologies. The IC drives N-channel MOSFET switches for DC/DC converters in applications up to 60V input. A high current gate drive output handles up to 10,000pF gate capacitance, enabling the construction of high power DC/DC converters. Current sense common mode range up to 60V allows current sensing to be referenced to the input supply, eliminating the need for sense blanking circuits. The LT1680 incorporates programmable average current limiting allowing accurate limiting of DC current in the magnetics, independent of ripple current. User adjustable slope compensation provides stable operation at duty cycles up to 90%. The LT1680 operating frequency is programmable and can be synchronized up to 200kHz. Minimum off-time operation provides switch protection. The IC also incorporates a soft start feature that is gated by both shutdown and undervoltage lockout conditions.

The LT138A/LT338A series of adjustable regulators provide 5A output current over an output voltage range of 1.2V to 32V. The internal voltage reference is trimmed to less than 1%, enabling a very tight output voltage. In addition to excel- lent line and load regulation, with full overload protection, the LT138A incorporates new current limiting circuitry allowing large transient load currents to be handled for short periods. Transient load currents of up to 12A can be supplied without limiting, eliminating the need for a large output capacitor. The LT138A is an improved version of the popular LM138 with improved circuit design and advanced process tech- niques to provide superior performance and reliability.

LT3485-0/LT3485-1/LT3485-2/LT3485-3 are photoflash capacitor chargers with output voltage monitor and integrated IGBT drive.

The LTC1569-7 is a 10th order lowpass filter featuring linear phase and a root raised cosine amplitude response. The high selectivity of the LTC1569-7 combined with its linear phase in the passband makes it suitable for filtering both in data communications and data acquisition sytems.

The LTC1798 series of micropower bandgap references combine high accuracy, low drift, 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 dissipa- tion 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.

The LTC1921 monitors two independent -48V supplies, including their fuses, and drives up to three optoisolators to indicate status, in accordance with standard backplane specifications. It features dual supply overvoltage and undervoltage detection circuits, and can ignore fast supply transients to eliminate false detection. The LTC1921 operates from -10V to -80V with a typical power dissipation of less than 10mW. It is available in an 8-pin MSOP package.

The LTC2248 / LTC2247 / LTC2246 are 14-bit 65Msps / 40Msps / 25Msps low power 3V A/D converters designed for digitizing high frequency, wide dynamic range signals. They are perfect for demanding imaging and communications applications.

The LTC1090 is a data acquisition component which contains a serial I/O successive approximation A/D converter. It uses LTCMOS switched capacitor technology to perform either 10-bit unipolar, or 9-bit plus sign bipolar A/D conversions. It has 4 differential/8 single ended input channels that can be configured for either single ended or differential inputs. It also includes an on-chip sample and hold circuit. The serial I/O is compatible with industry standard full duplex serial interfaces. The output data can be programmed for a length of 8, 10, 12 or 16 bits, allowing easy interface to shift registers and a variety of processors. The LTC1090A is specified with total unadjusted error less than ±0.5LSB.

The LT5534 is a 50MHz to 3GHz RF power detector with a dynamic range of 60dB. It features exceptional accuracy over temperature and power supply, fast transient response, and can be used for RF power detection, optical receiver gain control, etc.

The LTC1403/LTC1403A are 12-bit/14-bit, 2.8Msps serial ADCs with features such as low power dissipation and single supply operation.

LTC1196/LTC1198 are 600ns, 8-bit A/D converters with sampling rates up to 1MHz. They are offered in 8-pin SO packages and operate on 3V to 6V supplies. Power dissipation is only 10mW with a 3V supply or 50mW with a 5V supply. The LTC1198 automatically powers down to a typical supply current of 1nA whenever it is not performing conversions. These 8-bit switched-capacitor successive approximation ADCs include sample-and-holds. The LTC1196 has a differential analog input; the LTC1198 offers a software selectable 2-channel MUX. The 3-wire serial I/O, SO-8 packages, 3V operation and extremely high sample rate-to-power ratio make these ADCs an ideal choice for compact, high speed systems. These ADCs can be used in ratiometric applications or with external references. The high impedance analog inputs and the ability to operate with reduced spans below 1V full scale (LTC1196) allow direct connection to signal sources in many applications, eliminating the need for gain stages. These ADCs have low power consumption (10 mW), low noise (40 μV RMS) and high accuracy (±1/2LSB), making them suitable for a wide variety of applications, including data acquisition, motor control, instrumentation and power measurement.