The AD7788/AD7789 are low power, low noise, analog frontends for low frequency measurement applications. The AD7789contains a low noise, 24-bit, ∑-∆ analog-to-digital converter(ADC) with one differential input. The AD7788 is a 16-bitversion of the AD7789.The devices operate from an internal clock. Therefore, the userdoes not have to supply a clock source to the devices. The outputdata rate is 16.6 Hz, which gives simultaneous 50 Hz/60 Hzrejection.The devices operate with a single power supply from 2.5 V to5.25 V. When operating from a 3 V supply, the power dissipationfor the device is 225 µW maximum. The AD7788/AD7789 areavailable in a 10-lead MSOP.Applications Smart transmitters Battery applications Portable instrumentation Sensor measurement Temperature measurement Pressure measurement Weigh scales 4 to 20 mA loops

The AD7790/AD7791 are low-power, complete analog front ends for low frequency measurement applications. The device consumes 65 µA of current typically when operated with a 3 V power supply and 75 µA typical when operated with a 5 V power supply with the buffer disabled. The AD7791 contains a 24-bit S-D ADC with one differential input, which can be buffered or unbuffered. The AD7790 is a 16-bit version of the AD7791. The AD7790 has a peak-to-peak resolution of 16 bits at the default output data rate of 16.6 Hz while the AD7789 has a peak to peak resolution of 19 bits, which is equivalent to an effective resolution of 21.5 bits at this output data rate.The device operates from an internal clock. Therefore, the user does not have to supply a clock source to the device. The output data rate from the part is software programmable, allowing rates from 9.5 Hz to 120 Hz. The p-p resolution from the part varies with the programmed output data rate. With an output data rate of 16.6 Hz, simultaneous 50 Hz/60 Hz rejection is achieved. Power supply monitoring is also included.The part can be used in single conversion mode whereby the device powers up, performs a single conversion and then returns to powerdown mode. Alternatively, it can be operated in continuous mode. In continuous conversion mode, the part can be configured to continuously read i.e. the conversions are placed on the serial bus automatically as soon as a conversion is complete (the user does not need to write to the ADC to read the data), assuming that the serial clock is applied to the device.The AD7790/AD7791 is housed in a 10-lead MSOP package.

The AD7837 / AD7847 is a complete, dual, 12-bit multiplying digital-to-analog converter with output amplifiers on a monolithic CMOS chip. No external user trims are required to achieve full specified performance.Both parts are microprocessor compatible, with high speed data latches and interface logic. The AD7847 accepts 12-bit parallel data which is loaded into the respective DAC latch using the WR input and a separate Chip Select input for each DAC. The AD7837 has a double-buffered 8-bit bus interface structure with data loaded to the respective input latch in two write operations. An asynchronous LDAC signal on the AD7837 updates the DAC latches and analog outputs.The output amplifiers are capable of developing ±10 V across a 2 kΩ load. They are internally compensated with low input offset voltage due to laser trimming at wafer level.The amplifier feedback resistors are internally connected to VOUT on the AD7847.The AD7837 / AD7847 is fabricated in Linear Compatible CMOS (LC2MOS), an advanced, mixed technology process that combines precision bipolar circuits with low power CMOS logic.A novel low leakage configuration (U.S. Patent No. 4,590,456) ensures low offset errors over the specified temperature range.

The AD7874 is a four-channel simultaneous sampling, 12-bit data acquisition system. The part contains a high speed 12-bit ADC, on chip reference, on-chip clock and four track/hold amplifiers. This latter feature allows the four input channels to be sampled simultaneously, thus preserving the relative phase information of the four input channels, which is not possible if all four channels share a single track/hold amplifier. This makes the AD7874 ideal for applications such as phased-array sonar and ac motor controllers where the relative phase information is important.The aperture delay of the four track/hold amplifiers is small and specified with minimum and maximum limits. This allows several AD7874s to sample multiple input channels simultaneously without incurring phase errors between signals connected to several devices. A reference output/reference input facility also allows several AD7874s to be driven from the same reference source.In addition to the traditional dc accuracy specifications such as linearity, full-scale and offset errors, the AD7874 is also fully specified for dynamic performance parameters including distortion and signal-to-noise ratio.The AD7874 is fabricated in Analog Devices' Linear Compatible CMOWS (LC2MOS) process, a mixed technology process that combines precision bipolar circuits with low-power CMOS logic. The part is available in a 28-pin, 0.6' wide, plastic or hermetic dual-in-line package (DIP), in a 28-terminal leadless ceramic chip carrier (LCCC) and in a 28-pin SOIC.PRODUCT HIGHLIGHTS Simultaneous Sampling of Four Input Channels. Four input channels, each with its own track/hold amplifier, allow simultaneous sampling of input signals. Track/hold acquisition time is 2 µs, and the conversion time per channel is 8 µs, allowing 29 kHz sample rate for all four channels. Tight Aperture Delay Matching. The aperture delay for each channel is small and the aperture delay matching between the four channels is less than 4 ns. Additionally, the aperture delay specification has upper and lower limits allowing multiple AD7874s to sample more than four channels. Fast Microprocessor Interface. The high speed digital interface of the AD7874 allows direct connection to all modern 16-bit microprocessors and digital signal processors.APPLICATIONS Sonar Motor Controllers Adaptive Filters Digital Signal Processing

The AD7870 / AD7875 / AD7876 is a fast, complete, 12-bit A/D converter. It consists of a track/hold amplifier, 8 µs successive approximation ADC, 3 V buried Zener reference and versatile interface logic. The ADC features a self-contained internal clock which is laser trimmed to guarantee accurate control of conversion time. No external clock timing components are required; the on-chip clock may be overridden by an external clock if required.The parts offer a choice of three data output formats: a single, parallel, 12-bit word; two 8-bit bytes or serial data. Fast bus access times and standard control inputs ensure easy interfacing to modern microprocessors and digital signal processors.All parts operate from ±5 V power supplies. The AD7870 and AD7876 accept input signal ranges of ±3 V and ±10 V, respectively, while the AD7875 accepts a unipolar 0 V to +5 V input range. The parts can convert full power signals up to 50 kHz.The AD7870 / AD7875 / AD7876 feature dc accuracy specifications such as linearity, full-scale and offset error. In addition, the AD7870 and AD7875 are fully specified for dynamic performance parameters including distortion and signal-to-noise ratio.The parts are available in a 24-pin, 0.3 inch-wide, plastic or hermeticdual-in-line package (DIP). The AD7870 and AD7875 are available in a 28-pin plastic leaded chip carrier (PLCC), while the AD7876 is available and in a 24-pin small outline (SOIC) package.

The AD7880 is a high speed, low power, 12-bit A/D converter which operates from a single +5 V supply. It consists of a 3 µs track/hold amplifier, a 12 µs successive-approximation ADC, versatile interface logic and a multiple-input range circuit. The part also includes a power save feature.An internal resistor network allows the part to accept both unipolar and bipolar input signals while operating from a single +5 V supply. Fast bus access to modern microprocessors and digital signal processors.The AD7880 features a total throughput time of 15 µs and can convert full power signals up to 33 kHz with a sampling frequency of 66 kHz.In addition to the traditional dc accuracy specifications such as linearity, full scale and offset errors, the AD7880 is also fully specified for dynamic performance parameters including harmonic distortion and signal-to-noise ratio.The AD7880 is fabricated in Analog Devices' Linear Compatible CMOS (LC2MOS) process, a mixed technology process that combines precision bipolar circuits with low power CMOS logic. The part is available in a 24-pin, 0.3 inch wide, plastic or hermetic dual-in-line package (DIP) as well as a small 24-lead SOIC package.

The AD7880 is a high speed, low power, 12-bit A/D converter which operates from a single +5 V supply. It consists of a 3 µs track/hold amplifier, a 12 µs successive-approximation ADC, versatile interface logic and a multiple-input range circuit. The part also includes a power save feature.An internal resistor network allows the part to accept both unipolar and bipolar input signals while operating from a single +5 V supply. Fast bus access to modern microprocessors and digital signal processors.The AD7880 features a total throughput time of 15 µs and can convert full power signals up to 33 kHz with a sampling frequency of 66 kHz.In addition to the traditional dc accuracy specifications such as linearity, full scale and offset errors, the AD7880 is also fully specified for dynamic performance parameters including harmonic distortion and signal-to-noise ratio.The AD7880 is fabricated in Analog Devices' Linear Compatible CMOS (LC2MOS) process, a mixed technology process that combines precision bipolar circuits with low power CMOS logic. The part is available in a 24-pin, 0.3 inch wide, plastic or hermetic dual-in-line package (DIP) as well as a small 24-lead SOIC package.

The AD7896 is a fast, 12-bit ADC that operates from a single 2.7 V to 5.5 V supply and is housed in small 8-lead PDIP and 8-lead SOIC packages. The part contains an 8 µs successive approximation ADC, an on-chip track-and-hold amplifier, an on-chip clock, and a high speed serial interface.Output data from the AD7896 is provided via a high speed, serial interface port. This 2-wire serial interface has a serial clock input and a serial data output with the external serial clock accessing the serial data from the part.In addition to the traditional dc accuracy specifications, such as linearity, full-scale, and offset errors, the AD7896 is also specified for dynamic performance parameters, including harmonic distortion and signal-to-noise ratio.The part accepts an analog input range of 0 V to VDD and operates from a single 2.7 V to 5.5 V supply, consuming only 9 mW typical. The VDD input is also used as the reference for the part so that no external reference is required.The AD7896 features a high sampling rate mode and, for low power applications, a proprietary automatic power down mode where the part automatically goes into power down once con-version is complete and 'wakes up' before the next conversion cycle.The part is available in a small, 8-lead, 0.3'' wide, plastic or hermetic dual-in-line package (PDIP) and in an 8-lead, small outline IC (SOIC).PRODUCT HIGHLIGHTS Complete, 12-bit ADC in an 8-Lead Package. The AD7896 contains an 8 µs ADC, a track-and-hold amplifier, control logic, and a high speed serial interface, all in an 8-lead PDIP. The VDD input is used as the reference for the part, so no external reference is needed. This offers considerable space saving over alternative solutions. Low Power, Single-Supply Operation. The AD7896 operates from a single 2.7 V to 5.5 V supply and consumes only 9 mW typical. The automatic powerdown mode, where the part goes into power down once conversion is complete and “wakes up” before the next conversion cycle, makes the AD7896 ideal for battery-powered or portable applications. High Speed Serial Interface. The part provides high speed serial data and serial clock lines allowing for an easy, 2-wire serial interface arrangement.

The AD797 is a very low noise, low distortion operational amplifier ideal for use as a preamplifier. The low noise of 0.9 nV√Hz and low total harmonic distortion of -120 dB at audio bandwidths give the AD797 the wide dynamic range necessary for preamps in microphones and mixing consoles.Furthermore, the AD797's excellent slew rate of 20 V/µs and 110 MHz gain bandwidth make it highly suitable for low frequency ultrasound applications.The AD797 is also useful in IR and Sonar Imaging applications where the widest dynamic range is necessary. The low distortion and 16-bit settling time of the AD797 make it ideal for buffering the inputs to Sigma Delta ADCs or the outputs of high resolution DACs especially when they are used in critical applications such as seismic detection and spectrum analyzers. Key features such as a 50 mA output current drive and the specified power supply voltage range of ±5 to ±15 volts make the AD797 an excellent general purpose amplifier.APPLICATIONS Professional audio preamplifiers IR, CCD, and sonar imaging systems Spectrum analyzers Ultrasound preamplifiers Seismic detectors Σ-Δ ADC/DAC buffers

The AD7997 / AD7998 are 8-channel, 10- and 12-bit, low power,successive approximation ADCs with an I2C-compatibleinterface. The parts operate from a single 2.7 V to 5.5 V powersupply and feature a 2 µs conversion time. The parts contain an8-channel multiplexer and track-and-hold amplifier that canhandle input frequencies up to 11 MHz.The AD7997 / AD7998 provide a 2-wire serial interface that iscompatible with I2C interfaces. Each part comes in two versions,AD7997-0 / AD7998-0 and AD7997-1 / AD7998-1, and eachversion allows at least two different I2C addresses. The I2C interface on the AD7997-0/AD7998-0 supports standard andfast I2C interface modes. The I2C interface on the AD7997-1 / AD7998-1 supports standard, fast, and high speed I2C interface modes.The AD7997 / AD7998 normally remain in a shutdown statewhile not converting, and power up only for conversions. Theconversion process can be controlled using the CONVST pin,by a command mode where conversions occur across I2C writeoperations or an automatic conversion interval mode selectedthrough software control. The AD7997 / AD7998 require an external reference that shouldbe applied to the REFIN pin and can be in the range of 1.2 V toVDD. This allows the widest dynamic input range to the ADC. On-chip limit registers can be programmed with high andlow limits for the conversion result, and an open-drain, out-of-range indicator output (ALERT) becomes active when theprogrammed high or low limits are violated by the conversionresult. This output can be used as an interrupt.PRODUCT HIGHLIGHTS 2 µs conversion time with low power consumption. I2C-compatible serial interface with pin-selectable addresses. Two AD7997/AD7998 versions allow five AD7997/AD7998 devices to be connected to the same serial bus. The parts feature automatic shutdown while not converting to maximize power efficiency. Current consumption is 1 µA max when in shutdown mode at 3V. Reference can be driven up to the power supply. Out-of-range indicator that can be software disabled or enabled. One-shot and automatic conversion rates. Registers store minimum and maximum conversion results.

The AD8000 is an ultrahigh speed, high performance, currentfeedback amplifier. Using Analog Devices, Inc., proprietaryeXtra Fast Complementary Bipolar (XFCB) process, the amplifiercan achieve a small signal bandwidth of 1.5 GHz and a slewrate of 4100 V/μs.The AD8000 has low spurious-free dynamic range (SFDR) of75 dBc at 20 MHz and input voltage noise of 1.6 nV/√Hz. TheAD8000 can drive over 100 mA of load current with minimaldistortion. The amplifier can operate on +5 V to ±6 V. Thesespecifications make the AD8000 ideal for a variety of applications,including high speed instrumentation.With a differential gain of 0.02%, differential phase of 0.01°, and0.1 dB flatness out to 170 MHz, the AD8000 has excellent videospecifications, which ensure that even the most demandingvideo systems maintain excellent fidelity.The AD8000 power-down mode reduces the supply current to1.3 mA. The amplifier is available in a tiny 8-lead LFCSP package,as well as in an 8-lead SOIC package. The AD8000 is rated to workover the extended industrial temperature range (−40°C to +125°C).A triple version of the AD8000 (AD8003) is underdevelopment.Applications Professional video High speed instrumentation Video switching IF/RF gain stage CCD imaging

The AD8044 is a quad low power, voltage feedback, high speed amplifier designed to operate on +3 V, +5 V or ±5 V supplies. It has true single-supply capability with an input voltage range extending 200 mV below the negative rail and within 1 V of the positive rail.The output voltage swing extends to within 25 mV of each rail, providing the maximum output dynamic range. Additionally, it features gain flatness of 0.1 dB to 12 MHz while offering differential gain and phase error of 0.04% and 0.22° on a single +5 V supply. This makes the AD8044 ideal for video electronics such as cameras, video switchers or any high speed portable equipment. The AD8044's low distortion and fast settling make it ideal for active filter applications.The AD8044 offers low power supply current of 13.1 mA max and can run on a single +3.3 V power supply. These features are ideally suited for portable and battery powered applications where size and power are critical.The wide bandwidth of 150 MHz along with 170 V/µs of slew rate on a single +5 V supply make the AD8044 useful in many general purpose, high speed applications where dual power supplies of up to ±6 V and single supplies from +3 V to +12 V are needed. The AD8044 is available in 14-pin plastic DIP and SOIC.

A wideband current feedback operational amplifier, the AD811 is optimized for broadcast-quality video systems. The -3 dB bandwidth of 120 MHz at a gain of +2 and differential gain and phase of 0.01% and 0.01° (RL = 150 W) make the AD811 an excellent choice for all video systems. The AD811 is designed to meet a stringent 0.1 dB gain flatness specification to a bandwidth of 35 MHz (G = +2) in addition to the low differential gain and phase errors. This performance is achieved whether driving one or two back terminated 75 W  cables, with a low power supply current of 16.5 mA. Furthermore, the AD811 is specified over a power supply range of ±4.5 V to ±18 V.The AD811 is also excellent for pulsed applications where transient response is crititcal. It can achieve a maximum slew rate of greater than 2500 V/µs with a settling time of less than 25 ns to 0.1% on a 2 V step and 65 ns to 0.01% on a 10 V step.The AD811 is ideal as an ADC or DAC buffer in data acquisition systems due to its low distortion up to 10 MHz and its wide unity gain bandwidth. Because the AD811 is a current feedback amplifier, this bandwidth can be maintained over a wide range of gains. The AD811 also offers low voltage and current noise of 1.9nV/√Hz and 20 pA/√Hz, respectively, and excellent dc accuracy for wide dynamic range applications.

The AD8137 is a low cost differential driver with a rail-to-rail output that is ideal for driving ADCs in systems that are sensitive to power and cost. The AD8137 is easy to apply, and its internal common-mode feedback architecture allows its output common-mode voltage to be controlled by the voltage applied to one pin. The internal feedback loop also provides inherently balanced outputs as well as suppression of even-order harmonic distortion products. Fully differential and single-ended-to-differential gain configurations are easily realized by the AD8137. External feedback networks consisting of four resistors determine the closed-loop gain of the amplifier. The power-down feature is beneficial in critical low power applications.The AD8137 is manufactured on Analog Devices, Inc., proprietary second-generation XFCB process, enabling it to achieve high levels of performance with very low power consumption.The AD8137 is available in the small 8-lead SOIC package and 3 mm × 3 mm LFCSP package. It is rated to operate over the extended industrial temperature range of −40°C to +125°C.APPLICATIONS ADC drivers Portable instrumentation Battery-powered applications Single-ended-to-differential converters Differential active filters Video amplifiers Level shifters

The AD826 is a dual, high speed voltage feedback op amp. It is ideal for use in applications which require unity gain stability and high output drive capability, such as buffering and cable driving. The 50 MHz bandwidth and 350 V/µs slew rate make the AD826 useful in many high speed applications including: video, CATV, copiers, LCDs, image scanners and fax machines. The AD826 features high output current drive capability of 50 mA min per amp, and is able to drive unlimited capacitive loads. With a low power supply current of 15 mA max for both amplifiers, the AD826 is a true general purpose operational amplifier.The AD826 is ideal for power sensitive applications such as video cameras and portable instrumentation. The AD826 can operate from a single +5V supply, while still achieving 25 MHz of bandwidth. Furthermore the AD826 is fully specified from a single +5V to ±15V power supplies.The AD826 excels as an ADC/DAC buffer or active filter in data acquisition systems and achieves a settling time of 70 ns to 0.01%, with a low input offset voltage of 2mV max. The AD826 is available in small 8-pin plastic mini-DIP and SO packages.

The AD828 is a low cost, dual video op amp optimized for use in video applications which require gains of +2 or greater and high ouput drive capability, such as cable driving. Due to its low power and single supply functionality, along with excellent differential gain and phase errors, the AD828 is ideal for power sensitive applications such as video cameras and professional video equipment.With video specs like 0.1 dB flatness to 40 MHz and low differential gain and phase errors of 0.01% and 0.05°, along with 50 mA of output current per amplifier, the AD828 is an excellent choice for any video application. The 130 MHz gain bandwidth and 450 V/µs slew rate make the AD828 useful in many high speed applications including: video monitors, CATV, color copiers, image scanners and fax machines.The AD828 is fully specified for operation with a single +5 V power supply and with dual supplies from ±5 V to ±15 V. this power supply flexibility, coupled with a very low supply current of 15 mA and excellent ac characteristics under all power supply conditions, make the AD828 the ideal choice for many demanding yet power sensitive applications.The AD828 is a voltage feedback op amp which excels as a gain stage (gains>+2) or active filter and high speed video systems and achieves a settling time of 45 ns to 0.1%, with a low input offset voltage of 2 mV max.The AD828 is available in low cost, small 8-pin plastic mini-DIP and SOIC packages.

The AD8302 is a fully integrated system for measuring gain/loss and phase in numerous receive, transmit, and instrumentation applications. It requires few external components and a single supply of 2.7 V–5.5 V. The ac-coupled input signals can range from –60 dBm to 0 dBm in a 50 Ω system, from low frequencies up to 2.7 GHz. The outputs provide an accurate measurement of either gain or loss over a ±30 dB range scaled to 30 mV/dB, and of phase over a 0°–180° range scaled to 10 mV/degree. Both subsystems have an output bandwidth of 30 MHz, which may optionally be reduced by the addition of external filter capacitors. The AD8302 can be used in controller mode to force the gain and phase of a signal chain toward predetermined setpoints. The AD8302 comprises a closely matched pair of demodulating logarithmic amplifiers, each having a 60 dB measurement range. By taking the difference of their outputs, a measurement of the magnitude ratio or gain between the two input signals is available. These signals may even be at different frequencies, allowing the measurement of conversion gain or loss. The AD8302 may be used to determine absolute signal level by applying the unknown signal to one input and a calibrated ac reference signal to the other. With the output stage feedback connection disabled, a comparator may be realized, using the setpoint pins MSET and PSET to program the thresholds.The signal inputs are single-ended, allowing them to be matched and connected directly to a directional coupler. Their input impedance is nominally 3 kΩ at low frequencies. The AD8302 includes a phase detector of the multiplier type, but with precise phase balance driven by the fully limited signals appearing at the outputs of the two logarithmic amplifiers. Thus, the phase accuracy measurement is independent of signal level over a wide range. The phase and gain output voltages are simultaneously available at loadable ground referenced outputs over the standard output range of 0 V to 1.8 V. The output drivers can source or sink up to 8 mA. A loadable, stable reference voltage of 1.8 V is available for precise repositioning of the output range by the user. In controller applications, the connection between the gain output pin VMAG and the setpoint control pin MSET is broken. The desired setpoint is presented to MSET and the VMAG control signal drives an appropriate external variable gain device. Likewise, the feedback path between the phase output pin VPHS and its setpoint control pin PSET may be broken to allow operation as a phase controller. The AD8302 is fabricated on Analog Devices’ proprietary, high performance 25 GHz SOI complementary bipolar IC process. It is available in a 14-lead TSSOP package and operates over a –40°C to +85°C temperature range. An evaluation board is available.

The AD8302 is a fully integrated system for measuring gain/loss and phase in numerous receive, transmit, and instrumentation applications. It requires few external components and a single supply of 2.7 V–5.5 V. The ac-coupled input signals can range from –60 dBm to 0 dBm in a 50 Ω system, from low frequencies up to 2.7 GHz. The outputs provide an accurate measurement of either gain or loss over a ±30 dB range scaled to 30 mV/dB, and of phase over a 0°–180° range scaled to 10 mV/degree. Both subsystems have an output bandwidth of 30 MHz, which may optionally be reduced by the addition of external filter capacitors. The AD8302 can be used in controller mode to force the gain and phase of a signal chain toward predetermined setpoints. The AD8302 comprises a closely matched pair of demodulating logarithmic amplifiers, each having a 60 dB measurement range. By taking the difference of their outputs, a measurement of the magnitude ratio or gain between the two input signals is available. These signals may even be at different frequencies, allowing the measurement of conversion gain or loss. The AD8302 may be used to determine absolute signal level by applying the unknown signal to one input and a calibrated ac reference signal to the other. With the output stage feedback connection disabled, a comparator may be realized, using the setpoint pins MSET and PSET to program the thresholds.The signal inputs are single-ended, allowing them to be matched and connected directly to a directional coupler. Their input impedance is nominally 3 kΩ at low frequencies. The AD8302 includes a phase detector of the multiplier type, but with precise phase balance driven by the fully limited signals appearing at the outputs of the two logarithmic amplifiers. Thus, the phase accuracy measurement is independent of signal level over a wide range. The phase and gain output voltages are simultaneously available at loadable ground referenced outputs over the standard output range of 0 V to 1.8 V. The output drivers can source or sink up to 8 mA. A loadable, stable reference voltage of 1.8 V is available for precise repositioning of the output range by the user. In controller applications, the connection between the gain output pin VMAG and the setpoint control pin MSET is broken. The desired setpoint is presented to MSET and the VMAG control signal drives an appropriate external variable gain device. Likewise, the feedback path between the phase output pin VPHS and its setpoint control pin PSET may be broken to allow operation as a phase controller. The AD8302 is fabricated on Analog Devices’ proprietary, high performance 25 GHz SOI complementary bipolar IC process. It is available in a 14-lead TSSOP package and operates over a –40°C to +85°C temperature range. An evaluation board is available.

The OP727 is a precision dual rail-to-rail output single supply amplifier featuring micropower operation and rail to rail output ranges. The OP777, OP727 and OP747 amplifiers provide improved performance over the industry standard OP07 with ±15V supplies and offer the further advantages of true single supply operation down to +3.0V and smaller package options than any other high voltage precision bipolar amplifier. Outputs are stable with capacitive loads of over 1000pF. Supply current is less than 300 μA per amplifier at 5 V. 500 Ω series resistors protect the inputs, allowing input signal levels several voltsabove the positive supply without phase reversal.

The AD420 is a complete digital to current loop output converter, designed to meet the needs of the industrial control market. It provides a high precision, fully integrated, low cost single-chip solution for generating current loop signals in a compact 24-pin SOIC or PDIP package.The output current range can be programmed to 4 mA-20 mA, 0 mA-20 mA or an overrange function of 0 mA-24 mA. The AD420 can alternatively provide a voltage output from a separate pin that can be configured to provide 0 V-5 V, 0 V-10 V, ±5 V or ±10 V with the addition of a single external buffer amplifier.The 3.3 M Baud serial input logic design minimizes the cost of galvanic isolation and allows for simple connection to commonly used microprocessors. It can be used in three-wire or asynchronous mode and a serial-out pin is provided to allow daisy chaining of multiple DACs on the current loop side of the isolation barrier.The AD420 uses sigma-delta (SD) DAC technology to achieve 16-bit monotonicity at very low cost. Full-scale settling to 0.1% occurs within 3 ms. The only external components that are required (in addition to normal transient protection circuitry) are three low cost capacitors which are used in the DAC output filter.If the AD420 is going to be used at extreme temperatures and supply voltages, an external output transistor can be used to minimize power dissipation on the chip via the 'BOOST' pin.The FAULT DETECT pin signals when an open circuit occurs in the loop. The on-chip voltage reference can be used to supply a precision +5 V to external components in addition to the AD420 or, if the user desires temperature stability exceeding 25 ppm/°C, an external precision reference such as the AD586 can be used as the reference.The AD420 is available in a 24-pin SOIC and PDIP over the industrial temperature range of -40°C to +85°C.PRODUCT HIGHLIGHTS The AD420 is a single chip solution for generating 4 mA to 20 mA or 0 mA to 20 mA signals at the controller end of the current loop. The AD420 is specified with a power supply range from 12 V to 32 V. Output loop compliance is 0 V to VCC − 2.75 V. The flexible serial input can be used in 3-wire mode with SPI® or MICROWIRE® microcontrollers, or in asynchronous mode, which minimizes the number of control signals required. The serial data out pin can be used to daisy chain any number of AD420s together in 3-wire mode. At power-up, the AD420 initializes its output to the low end of the selected range. The AD420 has an asynchronous CLEAR pin, which sends the output to the low end of the selected range (0 mA, 4 mA, or 0 V). The AD420 BOOST pin accommodates an external transistor to off-load power dissipation from the chip. The offset of ±0.05% and total output error of ±0.15% can be trimmed if desired, using two external potentiometers.