The 3B Series Signal Conditioning I/O Subsystem provides a low cost, versatile method of interconnecting real world analog signals to a data acquisition, monitoring or control system. It is designed to interface directly to analog signals such as thermocouple, RTD, ac and dc Strain Gage, Torque Transducer, Frequency, LVDT, AD590/AC2626 solid state temperature sensor outputs, and millivolt or process current signals, and convert the inputs to standardized analog outputs compatible with high level analog I/O subsystems.The 3B Series Subsystem consists of a 19" relay rack, compatible universal mounting backplane and a family of plug-in input and output signal conditioning modules (up to 16 per rack). 8- and 4-channel backplanes are also available. Each backplane incorporates screw terminals for sensor inputs and current outputs and a connector for high level, single-ended outputs to the user’s equipment.Input and output modules are offered in both isolated (±1500 V peak) and nonisolated versions. The input modules feature complete signal conditioning circuitry optimized for specific sensors or analog signals, and provide high level analog outputs. Each input module provides two simultaneous outputs: 0 V to +10 V (or ±10 V) and 4–20 mA (or 0–20 mA). Output modules accept 0 V to +10 V (or ±10 V) single ended signals and provide an isolated or nonisolated 4–20 mA (or 0–20 mA) process signal. All modules feature a universal pinout and may be readily "mixed and matched" and interchanged without disrupting field wiring.Each backplane contains the provision for a subsystem power supply. The 3B Series Subsystem can operate either from a common dc/dc or ac power supply mounted on each backplane, or from externally provided dc power. Two LEDs are used to indicate that power is being applied.

The 3B Series Signal Conditioning I/O Subsystem provides a low cost, versatile method of interconnecting real world analog signals to a data acquisition, monitoring or control system. It is designed to interface directly to analog signals such as thermocouple, RTD, ac and dc Strain Gage, Torque Transducer, Frequency, LVDT, AD590/AC2626 solid state temperature sensor outputs, and millivolt or process current signals, and convert the inputs to standardized analog outputs compatible with high level analog I/O subsystems.The 3B Series Subsystem consists of a 19" relay rack, compatible universal mounting backplane and a family of plug-in input and output signal conditioning modules (up to 16 per rack). 8- and 4-channel backplanes are also available. Each backplane incorporates screw terminals for sensor inputs and current outputs and a connector for high level, single-ended outputs to the user’s equipment.Input and output modules are offered in both isolated (±1500 V peak) and nonisolated versions. The input modules feature complete signal conditioning circuitry optimized for specific sensors or analog signals, and provide high level analog outputs. Each input module provides two simultaneous outputs: 0 V to +10 V (or ±10 V) and 4–20 mA (or 0–20 mA). Output modules accept 0 V to +10 V (or ±10 V) single ended signals and provide an isolated or nonisolated 4–20 mA (or 0–20 mA) process signal. All modules feature a universal pinout and may be readily "mixed and matched" and interchanged without disrupting field wiring.Each backplane contains the provision for a subsystem power supply. The 3B Series Subsystem can operate either from a common dc/dc or ac power supply mounted on each backplane, or from externally provided dc power. Two LEDs are used to indicate that power is being applied.

The AD580 is a three-terminal, low cost, temperature compensated, bandgap voltage reference which provides a fixed 2.5 V output for inputs between 4.5 V and 30 V. A unique combination of advanced circuit design and laser-wafer trimmed thin-film resistors provide the AD580 with an initial tolerance of ±0.4%, a temperature stability of better than 10 ppm/°C and long-term stability of better than 250µV. In addition, the low quiescent current drain of 1.5 mA max offers a clear advantage over classical Zener techniques.The AD580 is recommended as a stable reference for all 8-, 10- and 12-bit D-to-A converters that require an external reference. In addition, the wide input range of the AD580 allows operation with 5 volt logic supplies making the AD580 ideal for digital panel meter applications or whenever only a single logic power supply is available.The AD580J, K, L and M are specified for operation over the 0°C to +70°C temperature range; the AD580S, T and U are specified for operation over the extended temperature range of -55°C to +125°C.

The LT1031/LT0070 are precision 10V references with ultralow drift and noise, extremely good long term stability, and almost total immunity to input voltage variations. The reference output will both source and sink up to 10mA and can be used as a shunt regulator (two terminal Zener) with the same precision characteristics as the three terminal connection. Special care has been taken to minimize thermal regulation effects and temperature induced hysteresis.The LT1031 reference is based on a buried Zener diode structure which eliminates noise and stability problems associated with surface breakdown devices. Further, a subsurface Zener exhibits better temperature drift and time stability than even the best band-gap references.Unique circuit design makes the LT1031 the first three terminal IC reference to offer ultralow drift without the use of high power on-chip heaters. Output voltage is pretrimmed to 0.05% accuracy.The LT1031 can be used as a plug-in replacement for the AD581 and LH0070*, with improved electrical and thermal performance.ApplicationsA-to-D and D-to-A ConvertersPrecision RegulatorsDigital Voltmeterslnertial Navigation SystemsPrecision ScalesPortable Reference Standard

The AD581 is a 3-pin, temperature compensated, monolithic, band gap voltage reference that provides a precise 10.00 V output from an unregulated input level ranging from 12 V to 30 V. Laser wafer trimming (LWT) is used to trim both the initial error at +25°C as well as the temperature coefficient, resulting in high precision performance previously available only in expensive hybrids or oven regulated modules. The 5 mV initial error tolerance and 5 ppm/°C guaranteed temperature coefficient of the AD581L is available in a monolithic voltage reference.The band gap circuit design used in the AD581 offers several advantages over classical Zener breakdown diode techniques. Most important, no external components are required to achieve full accuracy and significant stability to low power systems. In addition, total supply current to the device, including the output buffer amplifier (which can supply up to 10 mA) is typically 750 μA. The long-term stability of the band gap design is equivalent to selected Zener reference diodes.The AD581 is recommended for use as a reference for 8-, 10- or 12-bit digital-to-analog converters (DACs) that require an external precision reference. The device is also ideal for all types of analog-to-digital converters (ADCs) up to 14-bit accuracy, either successive approximation or integrating designs, and can generally offer better performance than that provided by standard self-contained references.The AD581J, K, and L are specified for operation from 0°C to +70°C; the AD581S, T, and U are specified for the -55°C to +125°C range. All grades are packaged in a hermetically sealed three-terminal TO-5 metal can.PRODUCT HIGHLIGHTSLaser trimming of both initial accuracy and temperature coefficient results in very low errors over temperature without the use of external components. The AD581L has a maximum deviation from 10.000 V of ±7.25 mV from 0°C to 70°C, whereas the AD581U guarantees ±15 mV maximum total error without external trims from −55°C to +125°C.Because the laser trimming is done on the wafer prior to separation into individual chips, the AD581 is extremely valuable to hybrid designers for its ease of use, lack of required external trims, and inherent high performance.The AD581 can also be operated in a 2-pin Zener mode to provide a precision −10 V reference with just one external resistor to the unregulated supply. The performance in this mode is nearly equal to that of the standard 3-pin configuration.Advanced circuit design using the band gap concept allows the AD581 to give full performance with an unregulated input voltage down to 13 V. With an external resistor, the device operates with a supply as low as 11.4 V. 5. The AD581 is available in versions compliant with MILSTD-883. Refer to the military datasheet for detailed specifications.

The AD585 is a complete monolithic sample-and-hold circuit consisting of a high performance operational amplifier in series with an ultralow leakage analog switch and a FET input integrating amplifier. An internal holding capacitor and matched applications resistors have been provided for high precision and applications flexibility.The performance of the AD585 makes it ideal for high speed 10- and 12-bit data acquisition systems, where fast acquisition time, low sample-to-hold offset, and low droop are critical. The AD585 can acquire a signal to ±0.01% in 3 µs maximum, and then hold that signal with a maximum sample-to-hold offset of 3 mV and less than 1 mV/ms droop, using the on-chip hold capacitor. If lower droop is required, it is possible to add a larger external hold capacitor.The high speed analog switch used in the AD585 exhibits aperture jitter of 0.5 ns, enabling the device to sample full scale (20 V peak-to-peak) signals at frequencies up to 78 kHz with 12-bit precision.The AD585 can be used with any user-defined feedback net-work to provide any desired gain in the sample mode. On-chip precision thin-film resistors can be used to provide gains of +1, -1, or +2. Output impedance in the hold mode is sufficiently low to maintain an accurate output signal even when driving the dynamic load presented by a successive-approximation A/D converter. However, the output is protected against damage from accidental short circuits.The control signal for the HOLD command can be either active high or active low. The differential HOLD signal is compatible with all logic families, if a suitable reference level is provided. An on-chip TTL reference level is provided for TTL compatibility.The AD585 is available in three performance grades. The JP grade is specified for the 0°C to +70°C commercial temperature range and packaged in a 20-pin PLCC. The AQ grade is specified for the -25°C to +85°C industrial temperature range and is packaged in a 14-pin cerdip. The SQ and SE grades are specified for the -55°C to +125°C military temperature range and are packaged in a 14-pin cerdip and 20-pin LCC.

The AD590 is a 2-terminal integrated circuit temperature trans-ducer that produces an output current proportional to absolute temperature. For supply voltages between 4 V and 30 V, the device acts as a high impedance, constant current regulator passing 1 μA/K. Laser trimming of the chip’s thin-film resistors is used to calibrate the device to 298.2 μA output at 298.2 K (25°C).The AD590 should be used in any temperature-sensing application below 150°C in which conventional electrical temperature sensors are currently employed. The inherent low cost of a monolithic integrated circuit combined with the elimination of support circuitry makes the AD590 an attractive alternative for many temperature measurement situations. Linearization circuitry, precision voltage amplifiers, resistance measuring circuitry, and cold junction compensation are not needed in applying the AD590.In addition to temperature measurement, applications include temperature compensation or correction of discrete components, biasing proportional to absolute temperature, flow rate measurement, level detection of fluids and anemometry. The AD590 is available in die form, making it suitable for hybrid circuits and fast temperature measurements in protected environments.The AD590 is particularly useful in remote sensing applications. The device is insensitive to voltage drops over long lines due to its high impedance current output. Any well-insulated twisted pair is sufficient for operation at hundreds of feet from the receiving circuitry. The output characteristics also make the AD590 easy to multiplex: the current can be switched by a CMOS multiplexer, or the supply voltage can be switched by a logic gate output.PRODUCT HIGHLIGHTSThe AD590 is a calibrated, 2-terminal temperature sensor requiring only a dc voltage supply (4 V to 30 V). Costly transmitters, filters, lead wire compensation, and linearization circuits are all unnecessary in applying the device.State-of-the-art laser trimming at the wafer level in conjunction with extensive final testing ensures that AD590 units are easily interchangeable.Superior interface rejection occurs because the output is a current rather than a voltage. In addition, power requirements are low (1.5 mW @ 5 V @ 25°C). These features make the AD590 easy to apply as a remote sensor.The high output impedance (>10 MΩ) provides excellent rejection of supply voltage drift. For instance, changing the power supply from 5 V to 10 V results in only a 1 μA maximum current change, or 1°C equivalent error.The AD590 is electrically durable: it withstands a forward voltage of up to 44 V and a reverse voltage of 20 V. Therefore, supply irregularities or pin reversal does not damage the device.

The AD7572 is a complete, 12-bit ADC that offers high speed performance combined with low, CMOS power levels. The AD7572 uses an accurate, high speed DAC and comparator in a successive-approximation loop to achieve a fast conversion time.An on-chip, buried Zener diode provides a stable reference voltage to give low drift performance over the full temperature range and the specified accuracy is achieved without any user trims. An on-chip clock circuit is provided, which may be used with a crystal for stand-alone operation, or the clock input may be driven from a external clock source such as a divided-down microprocessor clock. The only other external components required for basic operation of the AD7572 are decoupling capacitors for the supply voltages and reference output.

The AD670 is a complete 8-bit signal conditioning analog-to-digital converter. It consists of an instrumentation amplifier front end along with a DAC, comparator, successive approximation register (SAR), precision voltage reference, and a three-state output buffer on a single monolithic chip. No external components or user trims are required to interface, with full accuracy, an analog system to an 8-bit data bus. The AD670 will operate on the +5 V system supply. The input stage provides differential inputs with excellent common-mode rejection and allows direct interface to a variety of transducers.The device is configured with input scaling resistors to permit two input ranges: 0 mV to 255 mV (1 mV/LSB) and 0 to 2.55 V (10 mV/LSB). The AD670 can be configured for both unipolar and bipolar inputs over these ranges. The differential inputs and common-mode rejection of this front end are useful in applications such as conversion of transducer signals superimposed on common-mode voltages.The AD670 incorporates advanced circuit design and proven processing technology. The successive approximation function is implemented with I2L (integrated injection logic). Thin-film SiCr resistors provide the stability required to prevent missing codes over the entire operating temperature range while laser wafer trimming of the resistor ladder permits calibration of the device to within ±1 LSB. Thus, no user trims for gain or offset are required. Conversion time of the device is 10 µs.The AD670 is available in four package types and five grades. The J and K grades are specified over 0°C to +70°C and come in 20-pin plastic DIP packages or 20-terminal PLCC packages. The A and B grades (-40°C to +85°C) and the S grade (-55°C to +125°C) come in 20-pin ceramic DIP packages.The S grade is also available with optional processing to MIL-STD-883 in 20-pin ceramic DIP or 20-terminal LCC packages. The Analog Devices Military Products Databook should be consulted for detailed specifications.