The AD637 is a complete, high accuracy, rms-to-dc converter that computes the true rms value of any complex waveform. It offers performance that is unprecedented in integrated circuit rms-to-dc converters and comparable to discrete and modular techniques in accuracy, bandwidth, and dynamic range. The AD637 computes the true root mean square, mean square, or absolute value of any complex ac (or ac plus dc) input waveform and gives an equivalent dc output voltage. The true rms value of a waveform is more useful than an average rectified signal because it relates directly to the power of the signal. The rms value of a statistical signal relates to the standard deviation of the signal.Superior crest factor compensation permits measurements of signals with crest factors of up to 10 with less than 1% additional error. The wide bandwidth of the AD637 permits the measurement of signals up to 600 kHz with inputs of 200 mV rms and up to 8 MHz when the input levels are above 1 V rms.Direct dB value of the rms output with a range of 60 dB is available on a separate pin. An externally programmed reference current allows the user to select the 0 dB reference voltage to correspond to any level between 0.1 V and 2.0 V rms.A chip select connection on the AD637 permits the user to decrease the supply current from 2.2 mA to 350 µA during periods when the rms function is not in use. This feature facilitates the addition of precision rms measurement to remote or handheld applications where minimum power consumption is critical. In addition, when the AD637 is powered down, the output goes to a high impedance state. This allows several AD637s to be tied together to form a wideband true rms multiplexer.The input circuitry of the AD637 is protected from overload voltages in excess of the supply levels. The inputs are not damaged by input signals if the supply voltages are lost.The AD637 is laser wafer trimmed to achieve rated performance without external trimming. The only external component required is a capacitor that sets the averaging period. The value of this capacitor also determines low frequency accuracy, ripple level, and settling time.The on-chip buffer amplifier is used either as an input buffer or in an active filter configuration. The filter can be used to reduce the amount of ac ripple, thereby increasing accuracy.The AD637 is available in accuracy Grade J and Grade K for commercial temperature range (0°C to 70°C) applications, accuracy Grade A and Grade B for industrial range (−40°C to +85°C) applications, and accuracy Grade S rated over the −55°C to +125°C temperature range. All versions are available in hermetically sealed, 14-lead SBDIP, 14-lead CERDIP, and 16-lead SOIC_W packages.

The AD7266 is a dual, 12-bit, high speed, low power, successive approximation ADC that operates from a single 2.7 V to 5.25 V power supply and features throughput rates up to 2 MSPS. The device contains two ADCs, each preceded by a 3-channel multiplexer, and a low noise, wide bandwidth track-and-hold amplifier that can handle input frequencies in excess of 30 MHz.The conversion process and data acquisition use standard control inputs allowing easy interfacing to microprocessors or DSPs. The input signal is sampled on the falling edge of CS; conversion is also initiated at this point. The conversion time is determined by the SCLK frequency. There are no pipelined delays associated with the part.The AD7266 uses advanced design techniques to achieve very low power dissipation at high throughput rates. With 5 V supplies and a 2 MSPS throughput rate, the part consumes 6.2 mA maximum. The part also offers flexible power/throughput rate management when operating in normal mode as the quiescent current consumption is so low.The analog input range for the part can be selected to be a 0 V to VREF (or 2 × VREF) range, with either straight binary or twos complement output coding. The AD7266 has an on-chip 2.5 V reference that can be overdriven when an external reference is preferred. This external reference range is 100 mV to VDD.PRODUCT HIGHLIGHTS Two Complete ADC Functions Allow Simultaneous Sampling and Conversion of Two Channels. Each ADC has three fully/pseudo differential pairs, or six single-ended channels, as programmed. The conversion result of both channels is simultaneously available on separate data lines, or in succession on one data line if only one serial port is available. High Throughput with Low Power Consumption. The AD7266 offers a 1.5 MSPS throughput rate with 11.4 mW maximum power dissipation when operating at 3 V. The AD7266 offers both a standard 0 V to VREF input range and a 2 × V input range. No Pipeline Delay. The part features two standard successive approximation ADCs with accurate control of the sampling instant via a CS input and once off conversion control.

The AD7417 and AD7418 are 10-bit, 4-channel and single-channelADCs with an on-chip temperature sensor that can operate from asingle 2.7 V to 5.5 V power supply. The devices contain a 15 μssuccessive approximation converter, a 5-channel multiplexer, atemperature sensor, a clock oscillator, a track-and-hold, and areference (2.5 V). The AD7416 is a temperature-monitoring onlydevice in an 8-lead package.The temperature sensor on the parts can be accessed via multiplexerChannel 0. When Channel 0 is selected and a conversionis initiated, the resulting ADC code at the end of the conversiongives a measurement of the ambient temperature (±1°C @ 25°C).On-chip registers can be programmed with high and low temperaturelimits, and an open-drain overtemperature indicator (OTI)output is provided, which becomes active when a programmedlimit is exceeded.A configuration register allows programming of the sense of theOTI output (active high or active low) and its operating mode(comparator or interrupt). A programmable fault queue counterallows the number of out-of-limit measurements that mustoccur before triggering the OTI output to be set to preventspurious triggering of the OTI output in noisy environments.An I2C® compatible serial interface allows the AD7416/AD7417/AD7418 registers to be written to and read back. The threeLSBs of the AD7416/AD7417 serial bus address can be selected,which allows up to eight AD7416/AD7417 devices to be connectedto a single bus.The AD7417 is available in a narrow body, 0.15 inch, 16-lead,small outline package (SOIC) and in a 16-lead, thin shrink,small outline package (TSSOP). The AD7416 and AD7418 areavailable in 8-lead SOIC and MSOP packages. Product Highlights The AD7416/AD7417/AD7418 have an on-chip temperature sensor that allows an accurate measurement of the ambient temperature (±1°C @ 25°C, ±2°C overtemperature) to be made. The measurable temperature range is −40°C to +125°C. An overtemperature indicator is implemented by carrying out a digital comparison of the ADC code for Channel 0 (temperature sensor) with the contents of the on-chip TOTI setpoint register. The AD7417 offers a space-saving, 10-bit analog-to-digital solution with four external voltage input channels, an onchip temperature sensor, an on-chip reference, and a clock oscillator. The automatic power-down feature enables the AD7416/ AD7417/AD7418 to achieve superior power performance. At slower throughput rates, the part can be programmed to operate in a low power shutdown mode, allowing further savings in power consumption.Applications Data acquisition with ambient temperature monitoring Industrial process control Automotive Battery-charging applications Personal computers

The AD7537 contains two 12-bit current output DAC's on one monolithic chip. A seperate reference input is provided for each DAC. The dual DAC saves valuable board space, and the monolithic construction ensures excellent thermal tracking. Both DAC's are guaranteed 12-bit monotonic over the full temperature range.The AD7537 has a 2-byte (8LSBs, 4MSBs) loading structure. It is designed for right-justified data format. The control signals for registering loading are A0, A1, CS, WR and UPD. Data is loaded to the input registers when CS and WR are low. To transfer this data to the DAC registers, UPD must be taken low with WR.Added features on the AD7537 include an asynchronous CLR line which is very useful in calibration routines. When this is taken low, all registers are cleares. The double buffering of the data inputs allows simultaneous update of both DAC's. Also, each DAC has a seperate AGND line. This increases the device versatility; for instance one DAC may be operated with AGND biased while the other is connected in the standard configuration.The AD7537 is manufactured using the Linear Compatible CMOS (LC²MOS) process. It is speed compatible with most microprocessors and accepts TTL, 74HC an 5V CMOS logic level inputs.PRODUCT HIGHLIGHTS DAC to DAC Matching: Since both DACs are fabricated on the same chip, precise matching and tracking is inherent. Many applications which are not practical using two discrete DACs are now possible. Typical matching: 0.5%. Small Package Size: The AD7537 is packaged in small 24-pin 0.3' DIPs and in 28-terminal surface mount packages. Wide Power Supply Tolerance: The device operates on a +12 V to +15 V VDD, with ±10% tolerance on this nominal figure. All specifications are guaranteed over this range.APPLICATIONS Automatic Test Equipment Programmable Filters Audio Applications Synchro Applications Process Control

The AD7538 is a 14-bit monolithic CMOS digital-to-analog converter (DAC) that uses laser trimmed thin-film resistors to achieve excellent linearity.The DAC is loaded by a single 14-bit wide word using standard chip select and memory write logic. Double buffering, which is optional using LDAC, allows simultaneous updates in a system containing multiple AD7538s.A novel low leakage configuration enables the AD7538 to exhibit excellent output leakage current characteristics over the specified temperature range.The AD7538 is manufactured using the linear-compatible CMOS (LC2MOS) process. It is speed compatible with most microprocessors and accepts TTL or CMOS logic level inputs.

The AD7708/18 are complete analog front-ends for low frequency measurement applications. The AD7718 contains a 24-bit sigma delta ADC with PGA and can be configured as 4/5 fully-differential input channels or 8/10 pseudo-differential input channels. Two pins on the device are configurable as analog inputs or reference inputs. The AD7708 is a 16-bit version of the AD7718. Inputs signal ranges from 20mV to 2.56V can be directly converted using these ADCs. Signals can be converted directly from a transducer without the need for signal conditioning.

The AD7765 is a high performance, 24-bit sigma-delta (Σ-Δ) 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 AD7766/AD7766-1/AD7766-2 are high performance,24-bit, oversampled SAR analog-to-digital converters (ADCs).The AD7766/AD7766-1/AD7766-2 combine the benefits of alarge dynamic range and input bandwidth, consuming 15 mW,10.5 mW, and 8.5 mW power, respectively, and are contained ina 16-lead TSSOP package.Ideal for ultralow power data acquisition (such as PCI- and USBbasedsystems), the AD7766/AD7766-1/AD7766-2 provide 24-bitresolution. The combination of exceptional SNR, wide dynamicrange, and outstanding dc accuracy make the AD7766/AD7766-1/AD7766-2 ideally suited for measuring small signal changes over awide dynamic range. This is particularly suitable for applicationswhere small changes on the input are measured on larger ac ordc signals. In such an application, the AD7766/AD7766-1/AD7766-2 accurately gather both ac and dc information.The AD7766/AD7766-1/AD7766-2 include an on-board digitalfilter (complete with linear phase response) that acts to eliminateout-of-band noise by filtering the oversampled input voltage.The oversampled architecture also reduces front-end antialiasrequirements. Other features of the AD7766/AD7766-1/AD7766-2include a SYNC/PD (synchronization/power-down) pin, allowingthe synchronization of multiple AD7766/AD7766-1/AD7766-2devices. The addition of an SDI pin provides the option of daisychaining multiple AD7766/AD7766-1/AD7766-2 devices.The AD7766/AD7766-1/AD7766-2 operate from a 2.5 V supplyusing a 5 V reference. The devices operate from −40°C to +105°C. Applications Low power PCI/USB data acquisition systems Low power wireless acquisition systems Vibration analysis Instrumentation High precision medical acquisition

The AD7792/AD7793 are low power, low noise, complete analog front ends for high precision measurement applications. The AD7792/AD7793 contain a low noise 16-/24-bit Σ-Δ ADC with three differential analog inputs. The on-chip, low noise instrumentation amplifier means that signals of small amplitude can be interfaced directly to the ADC. With a gain setting of 64, the rms noise is 40 nV when the update rate equals 4.17 Hz.The devices contain a precision low noise, low drift internal band gap reference and can accept an external differential reference. Other on-chip features include programmable excitation current sources, burnout currents, and a bias voltage generator. The bias voltage generator sets the common-mode voltage of a channel to AVDD/2.The devices can be operated with either the internal clock or an external clock. The output data rate from the parts is software-programmable and can be varied from 4.17 Hz to 470 Hz.The parts operate with a power supply from 2.7 V to 5.25 V. They consume a current of 400 μA typical and are housed in a 16-lead TSSOP package.Applications Thermocouple measurements RTD measurements Thermistor measurements Gas analysis Industrial process control Instrumentation Portable instrumentation Blood analysis Smart transmitters Liquid/gas chromatography 6-digit DVM

The AD7804/AD7808 are quad/octal 10-bit digital-to-analog converters, with serial load capabilities, while the AD7805/AD7809 are quad/octal 10-bit digital-to-analog converters with parallel load capabilities. These parts operate from a +3.3 V to +5 V (10%) power supply and incorporates an on-chip reference. These DACs provide output signals in the form of VBIAS VSWING. VSWING is derived internally from VBIAS. On-chip control registers include a system control register and channel control registers. The system control register has control over all DACs in the package. The channel control registers allow individual control of DACs. The complete transfer function of each individual DAC can be shifted around the VBIAS point using an on-chip Sub DAC. All DACs contain double buffered data inputs, which allow all analog outputs to be simultaneously updated using the asynchronous LDAC input. ApplicationsOptical Disk Drives Instrumentation and Communication Systems Process Control and Voltage Setpoint Control Trim Potentiometer Replacement Automatic Calibration Data Sheet, Rev. A, 12/98