The AD7730 is a complete analog front end for weigh-scale and pressure measurement applications. The device accepts low-level signals directly from a transducer and outputs a serial digital word. The input signal is applied to a proprietary programmable gain front end based around an analog modulator.The modulator output is processed by a low pass programmable digital filter, allowing adjustment of filter cutoff, output rate and settling time.The part features two buffered differential programmable gain analog inputs as well as a differential reference input. The part operates from a single +5 V supply. It accepts four unipolar analog input ranges: 0 mV to ±10 mV, +20 mV, +40 mV and +80 mV and four bipolar ranges: ±10 mV, ±20 mV, ±40 mV and ±80 mV. The peak-to-peak resolution achievable directly from the part is 1 in 230,000 counts. An on-chip 6-bit DAC allows the removal of TARE voltages. Clock signals for synchronizing ac excitation of the bridge are also provided.The serial interface on the part can be configured for three-wire operation and is compatible with microcontrollers and digital signal processors. The AD7730 contains self-calibration and system calibration options, and features an offset drift of less than 5 nV/°C and a gain drift of less than 2 ppm/°C.The part is available in a 24-pin plastic DIP, a 24-lead SOIC and 24-lead TSSOP package.APPLICATIONS Weigh Scales Pressure Measurement

The AD7730 is a complete analog front end for weigh-scale and pressure measurement applications. The device accepts low-level signals directly from a transducer and outputs a serial digital word. The input signal is applied to a proprietary programmable gain front end based around an analog modulator.The modulator output is processed by a low pass programmable digital filter, allowing adjustment of filter cutoff, output rate and settling time.The part features two buffered differential programmable gain analog inputs as well as a differential reference input. The part operates from a single +5 V supply. It accepts four unipolar analog input ranges: 0 mV to ±10 mV, +20 mV, +40 mV and +80 mV and four bipolar ranges: ±10 mV, ±20 mV, ±40 mV and ±80 mV. The peak-to-peak resolution achievable directly from the part is 1 in 230,000 counts. An on-chip 6-bit DAC allows the removal of TARE voltages. Clock signals for synchronizing ac excitation of the bridge are also provided.The serial interface on the part can be configured for three-wire operation and is compatible with microcontrollers and digital signal processors. The AD7730 contains self-calibration and system calibration options, and features an offset drift of less than 5 nV/°C and a gain drift of less than 2 ppm/°C.The part is available in a 24-pin plastic DIP, a 24-lead SOIC and 24-lead TSSOP package.APPLICATIONS Weigh Scales Pressure Measurement

The AD7730 is a complete analog front end for weigh-scale and pressure measurement applications. The device accepts low-level signals directly from a transducer and outputs a serial digital word. The input signal is applied to a proprietary programmable gain front end based around an analog modulator.The modulator output is processed by a low pass programmable digital filter, allowing adjustment of filter cutoff, output rate and settling time.The part features two buffered differential programmable gain analog inputs as well as a differential reference input. The part operates from a single +5 V supply. It accepts four unipolar analog input ranges: 0 mV to ±10 mV, +20 mV, +40 mV and +80 mV and four bipolar ranges: ±10 mV, ±20 mV, ±40 mV and ±80 mV. The peak-to-peak resolution achievable directly from the part is 1 in 230,000 counts. An on-chip 6-bit DAC allows the removal of TARE voltages. Clock signals for synchronizing ac excitation of the bridge are also provided.The serial interface on the part can be configured for three-wire operation and is compatible with microcontrollers and digital signal processors. The AD7730 contains self-calibration and system calibration options, and features an offset drift of less than 5 nV/°C and a gain drift of less than 2 ppm/°C.The part is available in a 24-pin plastic DIP, a 24-lead SOIC and 24-lead TSSOP package.APPLICATIONS Weigh Scales Pressure Measurement

The AD7730L is a complete analog front end for weigh-scale and pressure measurement applications. The device accepts low-level signals directly from a transducer and outputs a serial digital word. Theinput signal is applied to a proprietary programmable gain front end based around an analog modulator. The modulator output is processed by a low pass programmable digital filter, allowing adjustment of filter cutoff, output rate and settling time.The part features two buffered differential programmable gain analog inputs as well as a differential reference input. The device operates from a single +5 V supply. It accepts four unipolar analog input ranges: 0 mV to +10 mV, +20 mV, +40 mV and +80 mV and four bipolar ranges: ±10 mV, ±20 mV, ±40 mV and ±80 mV. The peak-to-peak resolution achievable directly from the part is 1 in 110,000 counts. An on-chip 6-bit DAC allows the removal of TARE voltages. Clock signals for synchronizing ac excitation of the bridge are also provided.The serial interface on the part can be configured for three-wire operation and is compatible with microcontrollers and digital signal processors. The AD7730L contains self-calibration and system calibration options, and features an offset drift of less than 5 nV/°C and a gain drift of less than 3 ppm/°C. The part is available in a 24-lead SOIC and 24-lead TSSOP package. It is a lower power version of the AD7730 (approximately 1/3 the power).

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 AD7813 is a high speed, microprocessor-compatible,8-/10-bit analog-to-digital converter with a maximum through-putof 400 kSPS. The converter operates off a single +2.7 V to+5.5 V supply and contains a 2.3 ms successive approximationA/D converter, track/hold circuitry, on-chip clock oscillator and8-bit wide parallel interface. The parallel interface is designed toallow easy interfacing to microprocessors and DSPs. The 10-bitconversion result is read by carrying out two 8-bit read operations.The first read operation accesses the 8 MSBs of the ADCconversion result and the second read accesses the 2 LSBs.Using only address decoding logic the AD7813 is easily mappedinto the microprocessor address space.When used in its power-down mode, the AD7813 automaticallypowers down at the end of a conversion and powers up at thestart of a new conversion. This feature significantly reduces thepower consumption of the part at lower throughput rates. TheAD7813 can also operate in a high speed mode where the part isnot powered down between conversions. In this mode of operationthe part is capable of providing 400 kSPS throughput.The part is available in a small, 16-pin, 0.3' wide, plastic dual-in-line package (DIP), in a 16-pin, 0.15' wide, narrow bodysmall outline IC (SOIC) and in a 16-pin thin shrink small outlinepackage (TSSOP).

The AD7871 / AD7872 are fast, complete, 14-bit analog-to-digital converters (ADC). They consist of a track-and-hold amplifier, successive approximation ADC, 3 V buried Zener reference, and versatile interface logic. The ADC features a self-contained, laser trimmed internal clock, so no external clock timing components are required. The on-chip clock may be overridden to synchronize ADC operation to the digital system for minimum noise.The AD7871 offers a choice of three data output formats: a single, parallel, 14-bit word; two 8-bit bytes or a 14-bit serial data stream. The AD7872 is a serial output device only. The two parts are capable of interfacing to all modern microprocessors and digital signal processors.The AD7871 / AD7872 operate from ±5 V power supplies, accept bipolar input signals of ±3 V and can convert full power signals up to 41.5 kHz.In addition to the traditional dc accuracy specifications, the AD7871 / AD7872 are also fully specified for dynamic performance parameters including distortion and signal-to-noise ratio.Both devices are fabricated in Analog Devices, Inc., LC2MOS mixed technology process. The AD7871 is available in 28-pin PDIP, PLCC, and CERDIP packages. The AD7872 is available in a 16-pin PDIP, CERDIP, and SOIC packages.

The AD421 is a complete, loop-powered, digital to 4-20 mA converter, designed to meet the needs of smart transmitter manufacturers in the Industrial Control industry. It provides a high precision, fully integrated, low cost solution in a compact 16-pin package. The AD421 is ideal for extending the resolution of smart 4-20 mA transmitters at very low cost. The AD421 includes a selectable regulator that is used to power itself and other devices in the transmitter. This regulator provides either a +5 V, +3.3 V or +3 V regulated output voltage. The part also contains +1.25 V and +2.5 V precision references. The AD421 thus eliminates the need for a discrete regulator and voltage reference. The only external components required are a number of passive components and a pass transistor to span large loop voltages.The AD421 can be used with standard HART FSK protocol communication circuitry without any degradation in specified performance. The high speed serial interface is capable of operating at 10 Mbps and allows for simple connection to commonly-used microprocessors and microcontrollers via a standard three-wire serial interface.The sigma-delta architecture of the DAC guarantees 16-bit monotonicity while the integral nonlinearity for the AD421 is ±0.01%. The part provides a zero scale 4 mA output current with ±0.1% offset error and a 20 mA full-scale output current with ±0.2% gain error.The AD421 is available in a 16-pin, 0.3 inch-wide, plastic DIP and a 16-lead, 0.3 inch-wide, SOIC package. The part is specified over the industrial temperature range of -40°C to +85°C.

The AD5200 and AD5201 are programmable resistor devices, with 256 positions and 33 positions respectively, that can be digitally controlled through a 3-wire SPI serial interface. The terms programmable resistor, variable resistor (VR), and RDAC are commonly used interchangeably to refer to digital potentiometers. These devices perform the same electronic adjustment functionas a potentiometer or variable resistor. Both AD5200 / AD5201 contain a single variable resistor in the compact MSOP package. Each device contains a fixed wiper resistance at the wiper contact that taps the programmable resistance at a point determined by a digital code. The code is loaded in the serialinput register. The resistance between the wiper and either end point of the programmable resistor varies linearly with respect to the digital code transferred into the VR latch. Each variable resistor offers a completely programmable value of resistance, between the A terminal and the wiper, or the B terminal and the wiper. The fixed A-to-B terminal resistance of 10 kΩ or 50 kΩ has a nominal temperature coefficient of 500 ppm/°C. The VR has a VR latch that holds its programmed resistance value. The VR latch is updated from an SPI-compatible serial-to-parallel shift register that is loaded from a standard 3-wire serial-input digital interface. Eight data bits for the AD5200 and six databits for the AD5201 make up the data word that is clocked into the serial input register. The internal preset forces the wiper to the midscale position by loading 80H and 10H into AD5200 and AD5201 VR latches respectively. The SHDN pin forces the resistor to an end-to-end open-circuit condition on the A terminal and shorts the wiper to the B terminal, achieving a microwatt power shutdown state. When SHDN is returned to logic high, the previous latch setting puts the wiper in the same resistance setting prior to shutdown. The digital interface is still active during shutdown so that code changes can be made that will produce a new wiper position when the device is returned from shutdown.All parts are guaranteed to operate over the extended industrial temperature range of –40°C to +85°C.APPLICATIONS Mechanical Potentiometer Replacement Instrumentation: Gain, Offset Adjustment Programmable Voltage to Current Conversion Programmable Filters, Delays, Time Constants Line Impedance Matching

The AD538 is a monolithic real-time computational circuit which provides precision analog multiplication, division, and exponentiation. The combination of low input and output offset voltages and excellent linearity results in accurate computation over an unusually wide input dynamic range. Laser wafer trimming makes multiplication and division with errors as low as 0.25% of reading possible, while typical output offsets of 100 microV or less add to the overall off-the-shelf performance level. Real-time analog signal processing is further enhanced by the device's 400 kHz bandwidth.The AD538's overall transfer function is Vo=Vy(Vz/Vx)m. Programming a particular function is via pin strapping. No external components are required for one-quadrant (positive input) multiplication and division. Two-quadrant (bipolar numerator) division is possible with the use of external level shifting and scaling resistors. The desired scale factor for both multiplication and division can be set using the on-chip +2 V or +10 V references, or controlled externally to provide simultaneous multiplication and division. Exponentiation with an M value from 0.2 to 5 can be implemented with the addition of one or two external resistors. Direct log ratio computation is possible by utilizing only the log ratio and output sections of the chip. Access to the multiple summing junctions adds further to the AD538's flexibility. Finally, a wide power-supply range of ±4.5 V to ±18 V allows operation from standard ±5 V, ± 12 V and ± 15 V supplies. The AD538 is available in two accuracy grades (A and B) over the industrial (-25°C to +85°C) temperature range and one grade (S) over the military (-55°C to +125°C) temperature range. The device is packaged in an 18-pin TO-118 hermetic size-brazed ceramic DIP. A-grade chips are also available.APPLICATIONS One- or two-quadrant multiply/divide Log ratio computation Squaring/square rooting Trigonometric function approximations Linearization via curve fitting Precision AGC Power functions