The AD7715 is a complete analog front end for low frequency measurement applications. The part can accept low level input signals directly from a transducer and outputs a serial digital word. It employs a Σ-Δ conversion technique to realize up to 16 bits of no missing codes performance. The input signal is applied to a proprietary programmable gain front end based around an analog modulator. The modulator output is processed by an on-chip digital filter. The first notch of this digital filter can be programmed via the on-chip control register allowing adjustment of the filter cutoff and output update rate.The AD7715 features a differential analog input as well as a differential reference input. It operates from a single supply (3 V or 5 V). It can handle unipolar input signal ranges of 0 mV to 20 mV, 0 mV to 80 mV, 0 V to 1.25 V and 0 V to 2.5 V. It can also handle bipolar input signal ranges of ±20 mV, ±80 mV, ±1.25 V and ±2.5 V. These bipolar ranges are referenced to the negative input of the differential analog input. The AD7715 thus performs all signal conditioning and conversion for a single channel system.The AD7715 is ideal for use in smart, microcontroller, or DSP-based systems. It features a serial interface that can be configured for three-wire operation. Gain settings, signal polarity, and update rate selection can be configured in software using the input serial port. The part contains self-calibration and system calibration options to eliminate gain and offset errors on the part itself or in the system.CMOS construction ensures very low power dissipation, and power-down mode reduces the standby power consumption to 50 μW typical. The part is available in a 16-lead, 0.3 inch-wide, plastic dual-in-line package (PDIP) as well as a 16-lead 0.3 inch wide small outline (SOIC_W) package and a 16-lead TSSOP package.PRODUCT HIGHLIGHTS The AD7715 consumes less than 450 μA in total supply current at 3 V supplies and 1 MHz master clock, making it ideal for use in low-power systems. Standby current is less than 10 μA. The programmable gain input allows the AD7715 to accept input signals directly from a strain gage or transducer removing a considerable amount of signal conditioning. The AD7715 is ideal for microcontroller or DSP processor applications with a three-wire serial interface reducing the number of interconnect lines and reducing the number of optocouplers required in isolated systems. The part contains on-chip registers which allow software control over output update rate, input gain, signal polarity, and calibration modes. The part features excellent static performance specifications with 16-bits no missing codes, ±0.0015% accuracy, and low rms noise (<550 nV). Endpoint errors and the effects of temperature drift are eliminated by on-chip calibration options, which remove zero-scale and full-scale errors.

This device is a 7th order sigma-delta modulator that converts the analog input signal into a high speed 1-bit data stream. The part operates from a +5 V supply and accepts a differential input range of 0 V to +2.5 V or ±1.25 V centered about a common-mode bias. The analog input is continuously sampled by the analog modulator, eliminating the need for external sample and hold circuitry. The input information is contained in the output stream as a density of ones. The original information can be reconstructed with an appropriate digital filter.

The AD7722 is a complete low power, 16-bit, sigma-delta ADC. The part operates from a +5 V supply and accepts a differential input voltage range of 0 V to +2.5 V or ±1.25 V centered around a common-mode bias. The AD7722 provides 16-bit performance for input bandwidths up to 90.625 kHz. The part provides data at an output word rate of 195.3 kHz.The analog input is continuously sampled by an analog modulator eliminating the need for external sample-and-hold circuitry. The modulator output is processed by two Finite Impulse Response (FIR) digital filters in series. The on-chip filtering reduces the external antialias requirements to first order, in most cases. The group delay for the filter is 215.5 µs, while the settling time for a step input is 431 µs. The sample rate, filter corner frequency, and output word rate are set by an external clock that is nominally 12.5 MHz.Use of a single bit DAC in the modulator guarantees excellent linearity and dc accuracy. Endpoint accuracy is ensured by on-chip calibration. This calibration procedure minimizes the zero-scale and full-scale errors.Conversion data is provided at the output register through a flexible serial port or a parallel port. This offers 3-wire, high speed interfacing to digital signal processors. The serial interface operates in an internal clocking (master) mode, whereby an internal serial data clock and framing pulse are device outputs. Additionally, two AD7722s can be configured with the serial data outputs connected together. Each converter alternately transmits its conversion data on a shared serial data line.The part provides an accurate on-chip 2.5 V reference. A reference input/output function is provided to allow either the internal reference or an external system reference to be used as the reference source for the part.The AD7722 is available in a 44-pin PQFP package and is specified over the industrial temperature range from –40°C to +85°C.

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 AD7731 is a complete analog front-end for process controlapplications. The device has a proprietary programmable gainfront end that allows it to accept a range of input signal ranges,including low level signals, directly from a transducer. The sigma-deltaarchitecture of the part consists of an analog modulatorand a low pass programmable digital filter, allowing adjustmentof filter cutoff, output rate and settling time.The part features three buffered differential programmable gainanalog inputs (which can be configured as five pseudo-differentialinputs), as well as a differential reference input. The part operatesfrom a single +5 V supply and accepts seven unipolar analoginput ranges: 0 to +20 mV, +40 mV, +80 mV, +160 mV,+320 mV, +640 mV and +1.28 V, and seven bipolar ranges:±20 mV, ±40 mV, ±80 mV, ±160 mV, ±320 mV, ±640 mV and±1.28 V. The peak-to-peak resolution achievable directly fromthe part is 16 bits at an 800 Hz output rate. The part can switchbetween channels with 1 ms settling time and maintain a performancelevel of 13 bits of peak-to-peak resolution.The serial interface on the part can be configured for three-wireoperation and is compatible with microcontrollers and digitalsignal processors. The AD7731 contains self-calibration andsystem calibration options and features an offset drift of lessthan 5 nV/°C and a gain drift of less than 2 ppm/°C.The part is available in a 24-lead plastic DIP, a 24-lead SOICand 24-lead TSSOP package.APPLICATIONS Process Control PLCs/DCS Industrial Instrumentation

The AD7731 is a complete analog front-end for process controlapplications. The device has a proprietary programmable gainfront end that allows it to accept a range of input signal ranges,including low level signals, directly from a transducer. The sigma-deltaarchitecture of the part consists of an analog modulatorand a low pass programmable digital filter, allowing adjustmentof filter cutoff, output rate and settling time.The part features three buffered differential programmable gainanalog inputs (which can be configured as five pseudo-differentialinputs), as well as a differential reference input. The part operatesfrom a single +5 V supply and accepts seven unipolar analoginput ranges: 0 to +20 mV, +40 mV, +80 mV, +160 mV,+320 mV, +640 mV and +1.28 V, and seven bipolar ranges:±20 mV, ±40 mV, ±80 mV, ±160 mV, ±320 mV, ±640 mV and±1.28 V. The peak-to-peak resolution achievable directly fromthe part is 16 bits at an 800 Hz output rate. The part can switchbetween channels with 1 ms settling time and maintain a performancelevel of 13 bits of peak-to-peak resolution.The serial interface on the part can be configured for three-wireoperation and is compatible with microcontrollers and digitalsignal processors. The AD7731 contains self-calibration andsystem calibration options and features an offset drift of lessthan 5 nV/°C and a gain drift of less than 2 ppm/°C.The part is available in a 24-lead plastic DIP, a 24-lead SOICand 24-lead TSSOP package.APPLICATIONS Process Control PLCs/DCS Industrial Instrumentation

The AD7782 is a complete analog front end for low-frequency measurement applications. The 24-bit sigma-delta ADC contains two fully differential analog input channels that can be configured with a gain of 1 or 16 allowing full-scale input signal ranges of ±2.56 V or ± 160 mV from a +2.5 V differential reference input. The AD7782 has an extremely simple, read-only digital interface which can be operated in master mode or slave mode. There are no on-chip registers to be programmed. The input signal range and input channel selection are configured using two external pins.The device operates from a 32.768 kHz crystal with an on-chip PLL generating the required internal operating frequency. The output data rate from the part is fixed via the master clock at 19.79 Hz and provides simultaneous 50 Hz and 60 Hz rejection at this update rate. Eighteen-bit p-p resolution can be obtained at this update rate. The part operates from a single 3 V or 5 V supply. When operating from 3 V supplies, the power dissipation for the part is 3.9 mW. The AD7782 is available in a 16-lead TSSOP package. Another part in the AD778x family is the AD7783. It is similar to the AD7782 except it has two integrated current sources and only one differential input channel.APPLICATIONS Sensor Measurement Industrial Process Control Temperature Measurement Pressure Measurements Weigh Scales Portable Instrumentation

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 AD7821 is a high-speed, 8-bit, sampling, analog-to-digital converter that offers improved performance over the popular AD7820. It offers a conversion time of 660 ns (vs. 1.36 µs for the AD7820) and 100 kHz signal bandwidth (vs. 6.4 kHz). The sampling instant is better defined and occurs on the falling edge of WR or RD. The provision for a VSS pin (Pin 19) allows the part to operate from  ±5 V supplies and to digitize bipolar input signals. Alternatively, for unipolar inputs, the VSS pin can be grounded and the AD7821 will operate from a single +5 V supply, like the AD7820.The AD7821 has a built-in track-and-hold function capable of digitizing full-scale signals up to 100 kHz max. It also uses a half-flash conversion technique that eliminates the need to generate a CLK signal for the ADC.The AD7821 is designed with standard microprocessor control signals (CS, RD, WR, RDY, INT) and latched, three-state data outputs capable of interfacing to high-speed data buses. An overflow output (OFL) is also provided for cascading devices to achieve higher resolution.The AD7821 is fabricated in Linear-Compatible CMOS (LC2MOS), an advanced, mixed technology process combining precision bipolar circuits with low-power CMOS logic. The part features a low power dissipation of 50 mW.

The AD7851 is a high speed, 14-bit ADC which operate from a single 5V power supply. The ADC powers-up with a set of default conditions at which time it can be operated as a read-only ADC. The ADC contains self-calibration and system calibration options to ensure accurate operation over time and temperature and has a number of power down options for low power applications.The AD7851 is capable of 272kHz throughput rate. The input track-and-hold acquires a signal in 0.33 µs and features a pseudo-differential sampling scheme. The AD7851 has the added advantage of two input voltage ranges ( 0 to VREF, and -VREF/2 to +VREF/2 centered about VREF/2). Input signal range is to VDD and the part is capable of converting full-power signals to 140 kHz.CMOS construction ensures low power dissipation (60 mW typ) with power-down mode (5 µW typ). The part is available in 24- pin, 0.3 inch-wide dual-in-line package (DIP), 24 lead small outline (SOIC) and 24 lead small shrink outline (SSOP) packages.PRODUCT HIGHLIGHTS Single 5 V supply. Operates with reference voltages from 4 V to VDD. Analog input ranges from 0 V to VDD. System and self-calibration including power-down mode. Versatile serial I/O port.APPLICATIONS Digital Signal Processing Speech Recognition and Synthesis Spectrum Analysis DSP Servo Control Instrumentation and Control Systems High Speed Modems Automotive