The AD7741/AD7742 are a new generation of synchronous voltage-to-frequency converters (VFCs). The AD7741 is a single-channel version in an 8-lead package (SOIC/DIP) and the AD7742 is a multichannel version in a 16-lead package (SOIC/DIP). No user trimming is required to achieve the specified performance.The AD7741 has a single buffered input whereas the AD7742 has four buffered inputs that may be configured as two fully-differential inputs or three pseudo-differential inputs. Both parts include an on-chip +2.5 V bandgap reference that provides the user with the option of using this internal reference or an external reference.The AD7741 has a single-ended voltage input range from 0 V to REFIN. The AD7742 has a differential voltage input range from ?VREF to +VREF. Both parts operate from a single +5 V supply consuming typically 6 mA, and also contain a power down feature that reduces the current consumption to less than 35 ?A.Applications Low Cost Analog-to-Digital Conversion Signal Isolation AD7742 is obsolete

The AD7747 is a high-resolution, ?-? capacitance-to-digital converter (CDC). The capacitance to be measured is connected directly to the device inputs. The architecture features inherent high resolution (24-bit no missing codes, up to 19.5-bit effective resolution), high linearity (?0.01%), and high accuracy (?10 fF factory calibrated). The AD7747 capacitance input range is ?8 pF (changing), and it can accept up to 17 pF common-mode capacitance (not changing), which can be balanced by a programmable on-chip digital-to-capacitance converter (CAPDAC).The AD7747 is designed for single-ended or differential capacitive sensors with one plate connected to ground. For floating (not grounded) capacitive sensors, the AD7745 or AD7746 are recommended.The part has an on-chip temperature sensor with a resolution of 0.1?C and accuracy of ?2?C. The on-chip voltage reference and the on-chip clock generator eliminate the need for any external components in capacitive sensor applications. The part has a standard voltage input that, together with the differential reference input, allows easy interface to an external temperature sensor, such as an RTD, thermistor, or diode.The AD7747 has a 2-wire, I2C-compatible serial interface. The part can operate with a single power supply of 2.7 V to 5.25 V. It is specified over the automotive temperature range of ?40?C to +125?C and is housed in a 16-lead TSSOP package.ApplicationsAutomotive, industrial, and medical systems for:Pressure measurementPosition sensingProximity sensingLevel sensingFlowmetersImpurity detections

The AD7765 is a high performance, 24-bit sigma-delta (?-?) analog-to-digital converter (ADC). It combines wide input bandwidth, high speed, and performance of 112 dB dynamic range at a 156 kHz output data rate. With excellent dc specifications, the converter is ideal for high speed data acquisition of ac signals where dc data is also required.Using the AD7765 eases front-end antialias filtering requirements, simplifying the design process significantly. The AD7765 offers pin-selectable decimation rates of 128? and 256?. Other features include an integrated buffer to drive the reference, as well as a fully differential amplifier to buffer and level shift the input to the modulator.An overrange alert pin indicates when an input signal exceeds the acceptable range. The addition of internal gain and internal overrange registers makes the AD7765 a compact, highly integrated data acquisition device requiring minimal peripheral components.The AD7765 also offers a low power mode, significantly reducing power dissipation without reducing the output data rate or available input bandwidth.The differential input is sampled at up to 40 MSPS by an analog modulator. The modulator output is processed by a series of low-pass filters. The external clock frequency applied to the AD7765 determines the sample rate, filter corner frequencies, and output word rate.The AD7765 device boasts a full band on-board FIR filter. The full stop-band attenuation of the filter is achieved at the Nyquist frequency. This feature offers increased protection from signals that lie above the Nyquist frequency being aliased back into the input signal bandwidth.The reference voltage supplied to the AD7765 determines the input range. With a 4 V reference, the analog input range is ?3.2768 V differential, biased around a common mode of 2.048 V. This common-mode biasing is achieved using the on-chip differential amplifier, further reducing the external signal conditioning requirements.The AD7765 is available in a 28-lead TSSOP package and is specified over the industrial temperature range of ?40?C to +85?C.APPLICATIONS Data acquisition systems Vibration analysis Instrumentation

The LTC1700 is a current mode synchronous step-up DC/DC controller that drives external N-channel and P-channel power MOSFETs using a constant frequency PWM architecture. Current limiting is provided by sensing the voltage drop across the main MOSFET, eliminating the need of a sense resistor. This No RSENSE? technique helps the LTC1700 maintain high efficiency at heavy loads while Burst Mode operation ensures high efficiency at light loads, thus providing high efficiencies over a wide range of load currents.The LTC1700 operates at a minimum input voltage as low as 0.9V. The device boasts a ?1.5% output voltage accuracy and consumes only 200?A of quiescent current. In shutdown, it only draws 10?A.To prevent inductor current runaway, the duty cycle is limited to 90%. Overvoltage protection is also provided which shuts both the external MOSFETs off when tripped.High constant operating frequency of 530kHz allows the use of small inductors and output capacitors. The LTC1700 can also be synchronized between 400kHz to 750kHz. Burst Mode operation is inhibited when the device is externally clocked or when the SYNC/MODE pin is pulled low to reduce noise and RF interference.Applications Cellular Telephones Wireless Modems RF Communications 2.5V to 3.3V, 2.5V to 5V Converters Battery-Powered Equipment Telecom/Network Systems

The LTC1734 is a low cost, single cell, constant-current/constant-voltage Li-Ion battery charger controller. When combined with a few external components, the SOT-23 package forms a very small, low cost charger for single cell lithium-ion batteries.The LTC1734 is available in 4.1V and 4.2V versions with 1% accuracy. Constant current is programmed using a single external resistor between the PROG pin and ground. Manual shutdown is accomplished by floating the program resistor while removing input power automatically puts the LT1734 into sleep mode. Both the shutdown and sleep modes drain near zero current from battery.Charge current can be monitored via the voltage on the PROG pin allowing a microcontroller or ADC to read the current and determine when to terminate the charge cycle. The output driver is both current limited and thermally protected to prevent the LTC1734 from operating outside of safe limits. No external blocking diode is required.The LTC1734 can also function as a general purpose current source or as a current source for charging nickel-cadmium (NiCd) and nickel-metal-hydride (NiMH) batteries using external termination. Charge Current Vfloat LTC1734 180mA to 700mA 4.1V or 4.2V LTC1734L 50mA to 180mA 4.2V Applications Cellular Telephones Handheld Computers Digital Cameras Charging Docks and Cradles Low Cost and Small Size Chargers Programmable Current Source

The LTC3201 is an ultralow noise, constant frequency, charge pump DC/DC converter specifically designed for powering white LEDs. The part produces a low noise boosted supply capable of supplying 100mA of output current. LED current is regulated for accurate and stable backlighting. A 3-bit DAC provides output current adjust for brightness control.Low external parts count (one small flying capacitor and three small bypass capacitors) and small MSOP-10 package size make the LTC3201 ideally suited for space constrained applications. An input noise filter further reduces input noise, thus enabling direct connection to the battery. High switching frequency enables the use of small external capacitors.The LTC3201 contains overtemperature protection and can survive an indefinite output short to GND. Internal soft-start circuitry also prevents excessive inrush current on start-up. A low current shutdown feature disconnects the load from VIN and reduces quiescent current to less than 1?A.Applications White LED Backlighting Programmable Boost Current Source

The LTC1923 is a pulse width modulator intended for thermoelectric cooler (TEC) or heater applications requiring either unidirectional or bidirectional drive circuits. All of the necessary control circuitry and two sets of complementary output drivers are integrated into the LTC1923 to drive a full bridge, providing an efficient means of bidirectional current flow to the TEC. An accurate temperature control loop to stabilize the temperature of a laser diode system is easily achieved with the addition of just a few external components. Typical temperature setpoint accuracy of 0.1?C is achievable with the LTC1923. Adding an instrumentation amplifier front end allows setpoint stability of 0.01?C.The part features independent adjustable heating and cooling pulse-by-pulse current limit, current soft-start for controlled start-up, output slew rate control to reduce system noise, differential current sense and voltage amplifiers and a host of auxiliary circuits to protect the laser and provide redundant system monitoring.Applications Laser-Based Fiber Optic Links Medical Instruments CPU Temperature Regulators

DC391A-A: Demo Board for LTC5505 RF Power Detector with Buffered Output and >40dB Dynamic Range.

The LT1961 is a 1.25MHz monolithic boost switching regulator. A high efficiency 1.5A, 0.2? switch is included on the die together with all the control circuitry required to complete a high frequency, current-mode switching regulator. Current-mode control provides fast transient response and excellent loop stability.New design techniques achieve high efficiency at high switching frequencies over a wide operating voltage range. A low dropout internal regulator maintains consistent performance over a wide range of inputs from 24V systems to Li-Ion batteries. An operating supply current of 1mA maintains high efficiency, especially at lower output currents. Shutdown reduces quiescent current to 6?A. Maximum switch current remains constant at all duty cycles. Synchronization allows an external logic level signal to increase the internal oscillator from 1.5MHz to 2MHz.The LT1961 is available in an exposed pad, 8-pin MSOP package. Full cycle-by-cycle switch current limit protection and thermal shutdown are provided. High frequency operation allows the reduction of input and output filtering components and permits the use of chip inductors.Applications DSL Modems Portable Computers Battery-Powered Systems Distributed Power

DC442A: Demo Board for the LT1950 Single Switch PWM Controller with Auxiliary Boost Converter.