The AD5940 and AD5941 are high precision, low power analog front ends (AFEs) designed for portable applications that require high precision, electrochemical-based measurement techniques, such as amperometric, voltammetric, or impedance measurements. The AD5940/AD5941 is designed for skin impedance and body impedance measurements, and works with the AD8233 AFE in a complete bioelectric or biopotential measurement system. The AD5940/AD5941 is designed for electrochemical toxic gas sensing.The AD5940/AD5941 consist of two high precision excitation loops and one common measurement channel, which enables a wide capability of measurements of the sensor under test. The first excitation loop consists of an ultra low power, dual-output string, digital-to-analog converter (DAC), and a low power, low noise potentiostat. One output of the DAC controls the noninverting input of the potentiostat, and the other output controls the noninverting input of the transimpedance amplifier (TIA). This low power excitation loop is capable of generating signals from dc to 200 Hz.The second excitation loop consists of a 12-bit DAC, referred to as the high speed DAC. This DAC is capable of generating high frequency excitation signals up to 200 kHz.The AD5940/AD5941 measurement channel features a 16-bit, 800 kSPS, multichannel successive approximation register (SAR) analog-to-digital converter (ADC) with input buffers, a built in antialias filter, and a programmable gain amplifier (PGA). An input multiplexer (mux) in front of the ADC allows the user to select an input channel for measurement. These input channels include multiple external current inputs, external voltage inputs, and internal channels. The internal channels allow diagnostic measurements of the internal supply voltages, die temperature, and reference voltages.The current inputs include two TIAs with programmable gain and load resistors for measuring different sensor types. The first TIA, referred to as the low power TIA, measures low bandwidth signals. The second TIA, referred to as the high speed TIA, measures high bandwidth signals up to 200 kHz.An ultra low leakage, programmable switch matrix connects the sensor to the internal analog excitation and measurement blocks. This matrix provides an interface for connecting external transimpedance amplifier resistors (RTIAs) and calibration resistors. The matrix can also be used to multiplex multiple electronic measurement devices to the same wearable electrodes.A precision 1.82 V and 2.5 V on-chip reference source is available. The internal ADC and DAC circuits use this on-chip reference source to ensure low drift performance for the 1.82 V and 2.5 V peripherals.The AD5940/AD5941 measurement blocks can be controlled via direct register writes through the serial peripheral interface (SPI) interface, or, alternatively, by using a preprogrammable sequencer, which provides autonomous control of the AFE chip. 6 kB of static random access memory (SRAM) is partitioned for a deep data first in, first out (FIFO) and command FIFO. Measurement commands are stored in the command FIFO and measurement results are stored in the data FIFO. A number of FIFO related interrupts are available to indicate when the FIFO is full.A number of general-purpose inputs/outputs (GPIOs) are available and controlled using the AFE sequencer. The AFE sequencer allows cycle accurate control of multiple external sensor devices.The AD5940/AD5941 operate from a 2.8 V to 3.6 V supply and are specified over a temperature range of ?40?C to +85?C. The AD5940 is packaged in a 56-lead, 3.6 mm ? 4.2 mm WLCSP. The AD5941 is packaged in a 48-lead LFCSP.APPLICATIONS Electrochemical measurements Electrochemical gas sensors Potentiostat/amperometric/voltammetry/cyclic voltammetry Bioimpedance applications Skin impedance Body impedance Continuous glucose monitoring Battery impedance

The AD608 provides a low power, low distortion, low noise mixer as well as a complete, monolithic logarithmic/limiting amplifier that uses a successive-detection technique. In addition, the AD608 provides both a high speed received signal strength indicator (RSSI) output with 80 dB dynamic range and a hard-limited output. The RSSI output is from a two-pole postdemodulation low-pass filter and provides a loadable output voltage of 0.2 V to 1.8 V. The AD608 operates from a single 2.7 V to 5.5 V supply at a typical power level of 21 mW at 3 V.The RF and local oscillator (LO) bandwidths both exceed 500 MHz. In a typical IF application, the AD608 can accept the output of a 240 MHz surface acoustic wave (SAW) filter and down-convert it to a nominal 10.7 MHz IF with a conversion gain of 24 dB (ZIF = 165 ?). The AD608 logarithmic/limiting amplifier section handles any IF from low frequency (LF) up to 30 MHz.The mixer is a doubly balanced gilbert-cell mixer and operates linearly for RF inputs spanning ?95 dBm to ?15 dBm. It has a nominal ?5 dBm third-order intercept. An on-board LO preamplifier requires only ?16 dBm of LO drive. The current output of the mixer drives a reverse-terminated, industry-standard 10.7 MHz, 330 ? filter.The nominal logarithmic scaling is such that the output is +0.2 V for a sinusoidal input to the IF amplifier of ?75 dBm and +1.8 V at an input of +5 dBm; over this range, the logarithmic conformance is typically ?1 dB. The logarithmic slope is proportional to the supply voltage. A feedback loop automatically nulls the input offset of the first stage down to the submicrovolt level.The AD608 limiter output provides a hard-limited signal output at 400 mV p-p. The voltage gain of the limiting amplifier to this output is more than 100 dB. Transition times are 11 ns and the phase is stable to within ?3? at 10.7 MHz for signals from ?75 dBm to +5 dBm.The AD608 is enabled by a CMOS logic-level voltage input, with a response time of 200 ns. When disabled, the standby power is reduced to 300 ?W within 400 ns.The AD608 is specified for the industrial temperature range of ?25?C to +85?C for 2.7 V to 5.5 V supplies and ?40?C to +85?C for 3.0 V to 5.5 V supplies. This device comes in a 16-lead plastic SOIC.APPLICATIONS PHS, GSM, TDMA, FM, or PM receivers Battery-powered instrumentation Base station RSSI measurements

The AD7091 is a 12-bit successive approximation register analog-to-digital converter (SAR ADC) that offers ultralow power consumption (typically 367 ?A at 3 V and 1 MSPS) while achieving fast throughput rates (1 MSPS with a 50 MHz SCLK). The AD7091 operates from a single 2.09 V to 5.25 V power supply. The AD7091 also features an on-chip conversion clock and a high speed serial interface.The conversion process and data acquisition are controlled using a CONVST signal and an internal oscillator. The AD7091 has a serial interface that allows data to be read after the conversion while achieving a 1 MSPS throughput rate. The AD7091 uses advanced design and process techniques to achieve very low power dissipation at high throughput rates.The reference is derived internally from VDD. This design allows the widest dynamic input range to the ADC; that is, the analog input range for the AD7091 is from 0 V to VDD.PRODUCT HIGHLIGHTS Lowest power 12-bit SAR ADC available. High Throughput Rate with Ultralow Power Consumption. Flexible Power/Throughput Rate Management. Average power scales with the throughput rate. Power-down mode allows the average power consumption to be reduced when the device is not performing a conversion. Reference Derived from the Power Supply. Single Supply Operation. APPLICATIONS Battery-powered systems Handheld meters Medical instruments Mobile communications Instrumentation and control systems Data acquisition systems Optical sensors Diagnostic/monitoring functions Energy harvesting

The AD7156 delivers a complete signal processing solution for capacitive sensors, featuring an ultralow power converter with fast response time.The AD7156 uses an Analog Devices, Inc., capacitance-to-digital converter (CDC) technology, which combines features important for interfacing to real sensors, such as high input sensitivity and high tolerance of both input parasitic ground capacitance and leakage current.The integrated adaptive threshold algorithm compensates for any variations in the sensor capacitance due to environmental factors like humidity and temperature or due to changes in the dielectric material over time.By default, the AD7156 operates in standalone mode using the fixed power-up settings and indicates detection on two digital outputs. Alternatively, the AD7156 can be interfaced to a micro-controller via the serial interface, the internal registers can be programmed with user-defined settings, and the data and status can be read from the part.The AD7156 operates with a 1.8 V to 3.6 V power supply. It is specified over the temperature range of ?40?C to +85?C.ApplicationsButtons and switchesProximity sensingContactless switchingPosition detectionLevel detectionPortable products

TThe AD7172-2 is an intelligent, low noise, low power, multiplexed,?-? analog-to-digital converter (ADC) with 2- or 4-channel(fully differential/single-ended) inputs for low bandwidthsignals. The AD7172-2 has a maximum channel scan rate of6.21 kSPS (161 ?s) for fully settled data. The output data ratesrange from 1.25 SPS to 31.25 kSPS.The AD7172-2 integrates key analog and digital signal conditioningblocks to allow users to configure an individual setup for eachanalog input channel in use via the SPI. Integrated true rail-to-railbuffers on the analog inputs and external reference inputs provideeasy to drive high impedance inputs. The precision 2.5 V low drift(2 ppm/?C) band gap internal reference (with an output referencebuffer) adds embedded functionality to reduce the externalcomponent count.The digital filter allows simultaneous 50 Hz and 60 Hz rejectionat a 27.27 SPS output data rate. The user can switch betweendifferent filter options according to the demands of each channel inthe application, with further digital processing functions such asoffset and gain calibration registers, which are also configurable ona per channel basis. General-purpose inputs/outputs (GPIOs)control external multiplexers synchronous to the ADC conversiontiming.The specified operating temperature range is ?40?C to +105?C.The AD7172-2 is in a 24-lead TSSOP package.Applications Process control: PLC/DCS modules - Temperature and pressure measurement Medical and scientific multichannel instrumentation Chromatography

The AD7172-4 is a low noise, low power, multiplexed, ?-? analog-to-digital converter (ADC) with 4- or 8-channel (fully differential/single-ended) inputs for low bandwidth signals. The AD7172-4 has a maximum channel scan rate of 6.21 kSPS (161 ?s) for fully settled data. The output data rates range from 1.25 SPS to 31.25 kSPS.The AD7172-4 integrates key analog and digital signal conditioning blocks to allow users to configure an individual setup for each analog input channel in use via the SPI. Integrated true rail-to-rail buffers on the analog inputs and reference inputs provide easy to drive high impedance inputs.The digital filter allows simultaneous 50 Hz and 60 Hz rejection at a 27.27 SPS output data rate. The user can switch between different filter options according to the demands of each channel in the application, with further digital processing functions such as offset and gain calibration registers, which are configurable on a per channel basis. General-purpose input/outputs (GPIOs) control external multiplexers synchronous to the ADC conversion timing. The specified temperature range is ?40?C to +105?C.The AD7172-4 is in a 5 mm ? 5 mm, 32-lead LFCSP.Note that, throughout this data sheet, the dual function pinnames are referenced by the relevant function only. Applications Process control: PLC/DCS modules Temperature and pressure measurement Medical and scientific multichannel instrumentation Chromatography

The AD7175-8 is a low noise, fast settling, multiplexed, 8-/16- channel (fully/pseudo differential) ?-? analog-to-digital converter (ADC) for low bandwidth inputs. It has a maximum channel scan rate of 50 kSPS (20 ?s) for fully settled data. The output data rates range from 5 SPS to 250 kSPS.The AD7175-8 integrates key analog and digital signal condition-ing blocks to allow users to configure an individual setup for each analog input channel in use. Each feature can be user selected on a per channel basis. Integrated true rail-to-rail buffers on the analog inputs and external reference inputs provide easy to drive high impedance inputs. The precision 2.5 V low drift (2 ppm/?C) band gap internal reference (with output reference buffer) adds embedded functionality to reduce external component count.The digital filter allows simultaneous 50 Hz and 60 Hz rejection at a 27.27 SPS output data rate. The user can switch between different filter options according to the demands of each channel in the application. The ADC automatically switches through each selected channel. Further digital processing functions include offset and gain calibration registers, configurable on a per channel basis.The device operates with a 5 V AVDD1 . AVSS supply, or with ?2.5 V AVDD1/AVSS, and 2.5 V to 5 V AVDD2 and IOVDD supplies. The specified operating temperature range is .40?C to +105?C. The AD7175-8 is available in a 40-lead LFCSP package.APPLICATIONS Process control: PLC/DCS modules Temperature and pressure measurement Medical and scientific multichannel instrumentation Chromatography

The AD7176-2 is a fast settling, highly accurate, high resolution,multiplexed ?-? analog-to-digital converter (ADC) for low bandwidthinput signals. Its inputs can be configured as two fullydifferential or four pseudo differential inputs via the integratedcrosspoint multiplexer. An integrated precision, 2.5 V, low drift(2 ppm/?C), band gap internal reference (with an outputreference buffer) adds functionality and reduces the externalcomponent count.The maximum channel scan data rate is 50 kSPS/channel(settling time of 20 ?s), resulting in fully settled data with17 noise free bits. User-selectable output data rates range from5 SPS to 250 kSPS. The resolution increases at lower speeds.The AD7176-2 offers three key digital filters. The fast settlingsinc5 + sinc1 filter maximizes the channel scan rate. The sinc3filter maximizes the resolution for single-channel, low speedapplications. For 50 Hz and 60 Hz environments, the AD7176-2specific filter minimizes the settling times or maximizes therejection of the line frequency. These enhanced filters enablesimultaneous 50 Hz and 60 Hz rejection with a 27 SPS outputdata rate (with a settling time of 36 ms).System offset and gain errors can be corrected on a per channelbasis. This per channel configurability extends to the output datarate used for each channel when using a sinc5 + sinc1 filter. Allswitching of the crosspoint multiplexer is controlled by the ADCand can be configured to automatically control an externalmultiplexer via the GPIO pins.The specified operating temperature range is ?40?C to +105?C.The AD7176-2 is housed in a 24-lead TSSOP package.Applications Process control: PLC/DCS modules - Temperature and pressure measurement Medical and scientific multichannel instrumentation Chromatography

The AD7193 is a low noise, complete analog front end for high precision measurement applications. It contains a low noise, 24-bit sigma-delta (?-?) analog-to-digital converter (ADC). The on-chip low noise gain stage means that signals of small amplitude can interface directly to the ADC.The device can be configured to have four differential inputs or eight pseudo differential inputs. The on-chip channel sequencer allows several channels to be enabled simultaneously, and the AD7193 sequentially converts on each enabled channel, simplifying communication with the part. The on-chip 4.92 MHz clock can be used as the clock source to the ADC or, alternatively, an external clock or crystal can be used. The output data rate from the part can be varied from 4.7 Hz to 4.8 kHz.The device has a very flexible digital filter, including a fast settling option. Variables such as output data rate and settling time are dependent on the option selected. The AD7193 also includes a zero latency option.The part operates with a power supply from 3 V to 5.25 V. It consumes a current of 4.65 mA, and it is available in a 28-lead TSSOP package and a 32-lead LFCSP package.Applications PLC/DCS analog input modules Data acquisition Strain gage transducers Pressure measurement Temperature measurement Flow measurement Weigh scales Chromatography Medical and scientific instrumentation

The AD7195 is a low noise, complete analog front end for high precision measurement applications. It contains a low noise, 24-bit sigma-delta (?-?) analog-to-digital converter (ADC). The on-chip low noise gain stage means that signals of small amplitude can be interfaced directly to the ADC. The AD7195 contains ac excitation, which is used to remove dc-induced offsets from bridge sensors.The device can be configured to have two differential inputs or four pseudo differential inputs. The on-chip channel sequencer allows several channels to be enabled, and the AD7195 sequentially converts on each enabled channel. This simplifies communication with the part. The on-chip 4.92 MHz clock can be used as the clock source to the ADC or, alternatively, an external clock or crystal can be used. The output data rate from the part can be varied from 4.7 Hz to 4.8 kHz.The device has two digital filter options. The choice of filter affects the rms noise/noise-free resolution at the programmed output data rate, the settling time, and the 50 Hz/60 Hz rejection. For applications that require all conversions to be settled, the AD7195 includes a zero latency feature.The part operates with a 5 V analog power supply and a digital power supply from 2.7 V to 5.25 V. It consumes a current of 6 mA. It is housed in a 32-lead LFCSP package.Applications Weigh scales Strain gage transducers Pressure measurement Temperature measurement Chromatography PLC/DCS analog input modules Data acquisition Medical and scientific instrumentation