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.

The AD7719 is a complete analog front-end for low frequency measurement applications. It contains two high-resolution sigma delta ADCs, switchable matched excitation current sources, low-side power switches, digital I/O port and temperature sensor. The 24-bit mainchannel with PGA accepts fully differential, unipolar and bipolar input signal ranges from REFIN1/128 to REFIN1. Signals can be converted directly from a transducer without the need for signal conditioning. The 16-bit aux channel does not have a PGA and has an input signal range of REFIN2 or REFIN2/2.

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 ADM1085-ADM1088 are Simple Sequencing™ circuits which provide a time delay between the enabling of voltage regulators at power-up in multiple supply systems. When the output voltage of the first regulator reaches a preset threshold, a time delay is initiated before an enable signal allows subsequent regulators to power-up. Any number of these devices can be cascaded with regulators to allow sequencing of multiple power supplies.Threshold levels can be set with a pair of external resistors in a voltage divider configuration. By choosing appropriate resistor values, the threshold can be adjusted to monitor voltages as low as 0.6V. The ADM1086 and ADM1088 have push-pull output stages, with active-high (ENOUT) and active-low (ENOUT) logic outputs, respectively. Similarly, the ADM1085 has an active-high (ENOUT) logic output and the ADM1087 has an active-low (ENOUT) output. Both the ADM1085 and ADM1087 have open-drain output stages which can be pulled up to voltage levels as high as 22V through an external resistor. This level shifting property of the ADM1085 and ADM1087 ensures compatibility with enable input logic levels of different regulators and converters.All four models have a dedicated enable input pin which allows the output signal to the regulator to be controlled externally. This is an active-high input (ENIN) for the ADM1085 and ADM1086, and an active-low input (ENIN) for the ADM1087 and ADM1088. The Simple Sequencers™ are specified over the extended –40°C to +125°C temperature range, and with low current consumption of 15µA (typ) and 6-lead SC70 packaging, they are suitable for low power portable applications.

The ADM3202 / ADM3222 / ADM1385 are high speed, 2-channel RS232/V.28 interface devices which operate from a single +3.3 V power supply. Low power consumption and a shutdown facility (ADM3222 / ADM1385) makes them ideal for battery powered portable instruments.The ADM3202 / ADM3222 / ADM1385 conform to the EIA-232E and CCITT V.28 specifications and operate at data rates up to 230 kbps. Four external 0.1 µF charge pump capacitors are used for the voltage doubler/inverter permitting operation from a single +3.3 V supply.The ADM3222 / ADM1385 contain additional enable and shutdown circuitry. The EN input may be used to three-state the receiver outputs. The SD input is used to power down the charge pump and transmitter outputs reducing the quiescent current to less than 1 µA. The receivers remain enabled during shutdown unless disabled using EN.The ADM3202 is available in a 16-lead DIP, narrow and wide SO as well as a space saving TSSOP package. The ADM3222 is available in 18 lead DIP , SO and in 20 lead SSOP and TSSOP. The ADM1385 is available in a 20 lead SSOP package and is pin compatible with the LTC1385 CG.

The ADM181x range of voltage monitoring circuits can be used in any application where an electronic system needs to be reset when a voltage increases above or below a predetermined value.Because of the “reset delay time” incorporated into the ADM181xseries, these devices can provide a safe startup for electronic systems. Before a system initializes, the power supply must stabilize. Using the ADM181x series ensures that there are typically 150 ms for the power supply to stabilize before the system is reset and safe system initialization begins.The ADM181x series of microprocessor reset circuits are available in low cost, space-saving SOT-23 packages.

The ADM181x range of voltage monitoring circuits can be used in any application where an electronic system needs to be reset when a voltage increases above or below a predetermined value.Because of the “reset delay time” incorporated into the ADM181x series, these devices can provide a safe startup for electronic systems. Before a system initializes, the power supply must stabilize. Using the ADM181x series ensures that there are typically 150 ms for the power supply to stabilize before the system is reset and safe system initialization begins.The ADM181x series of microprocessor reset circuits are available in low cost, space-saving SOT-23 packages.APPLICATIONS Microprocessor systems Computers Controllers Intelligent instruments Automotive systems

The ADM222, ADM232A, ADM242 are a family of high-speedRS-232 line drivers/receivers offering transmission rates up to200 kB/s. Operating from a single 5 V power supply, a highlyefficient on-chip charge pump using small (0.1 µF) externalcapacitors allows RS-232 bipolar levels to be developed. TwoRS-232 drivers and two RS-232 receivers are provided oneach device.The devices are fabricated on BiCMOS, an advanced mixedtechnology process that combines low power CMOS with highspeedbipolar circuitry. This allows for transmission rates up to200 kB/s, yet minimizes the quiescent power supply current tounder 5 mA.The ADM232A is a pin-compatible, high-speed upgrade for theAD232 and for the ADM232L. It is available in 16-lead DIPand in both narrow and wide surface-mount (SOIC) packages.The ADM222 contains an additional shutdown (SHDN) functionthat may be used to disable the device, thereby reducing thesupply current to 0.1 µA. During shutdown, all transmit/receivefunctions are disabled. The ADM222 is available in 18-leadDIP and in a wide surface-mount (SOIC) package.The ADM242 combines both shutdown (SHDN) and enable(EN) functions. The shutdown function reduces the supplycurrent to 0.1 mA. During shutdown, the transmitters are disabledbut the receivers continue to operate normally. Theenable function allows the receiver outputs to be disabledthereby facilitating sharing a common bus. The ADM242 isavailable in 18-lead DIP and in a wide surface-mount (SOIC)package.Applications Computers Peripherals Modems Printers Instruments

The ADM2483 differential bus transceiver is an integrated,galvanically isolated component designed for bidirectional datacommunication on balanced, multipoint bus transmission lines.It complies with ANSI EIA/TIA-485-A and ISO 8482: 1987(E).Using the iCoupler technology from Analog Devices, Inc., theADM2483 combines a 3-channel isolator, a three-state differentialline driver, and a differential input receiver into a single package.The logic side of the device is powered with either a 5 V or 3 Vsupply, and the bus side uses a 5 V supply only.The ADM2483 is slew-limited to reduce reflections withimproperly terminated transmission lines. The controlled slewrate limits the data rate to 500 kbps. The device’s input impedanceis 96 kΩ, allowing up to 256 transceivers on the bus. Its driverhas an active-high enable feature. The driver differential outputsand receiver differential inputs are connected internally to forma differential input/output (I/O) port.When the driver is disabled or when VDD1 or VDD2 = 0 V, thisimposes minimal loading on the bus. An active-high receiverdisable feature, which causes the receive output to enter a highimpedance state, is provided as well.The receiver inputs have a true fail-safe feature that ensures alogic-high receiver output level when the inputs are open orshorted. This guarantees that the receiver outputs are in aknown state before communication begins and at the pointwhen communication ends.Current limiting and thermal shutdown features protect againstoutput short circuits and bus contention situations that mightcause excessive power dissipation. The part is fully specifiedover the industrial temperature range and is available in a16-lead, wide body SOIC package.Applications Low power RS-485/RS-422 networks Isolated interfaces Building control networks Multipoint data transmission systems