AD7705BN DIP16 2-Kanal 16-Bit Sigma-Delta-ADC The AD7705/AD7706 are complete analog front ends for low frequency measurement applications. These 2-/3-channel devices can accept low level input signals directly from a transducer and produce serial digital output. The devices employ a Σ-Δ conversion technique to realize up to 16 bits of no missing codes performance. The selected 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 pro- grammed via an on-chip control register, allowing adjustment of the filter cutoff and output update rate. The AD7705/AD7706 devices operate from a single 2.7 V to 3.3 V or 4.75 V to 5.25 V supply. The AD7705 features two fully differential analog input channels; the AD7706 features three pseudo differential input channels. Both devices feature a differential reference input. Input signal ranges of 0 mV to 20 mV through 0 V to 2.5 V can be incorporated on both devices when operating with a VDD of 5 V and a reference of 2.5 V. They can also handle bipolar input signal ranges of ±20 mV through ±2.5 V, which are referenced to the AIN(−) inputs on the AD7705 and to the COMMON input on the AD7706. 3 V/5 V, 1 mW, 2-/3-Channel, 16-Bit, Sigma-Delta ADCs AD7705/AD7706 Rev. C Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibilityisassumedbyAnalogDevicesforitsuse,norforanyinfringementsofpatentsorother rightsofthirdpartiesthatmayresultfromitsuse.Specificationssubjecttochangewithoutnotice.No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2006 Analog Devices, Inc. All rights reserved. FEATURES - AD7705: 2 fully differential input channel ADCs - AD7706: 3 pseudo differential input channel ADCs - 16 bits no missing codes - 0.003% nonlinearity - Programmable gain front end: gains from 1 to 128 - 3-wire serial interface - SPI®-, QSPI™-, MICROWIRE™-, and DSP-compatible - Schmitt-trigger input on SCLK - Ability to buffer the analog input - 2.7 V to 3.3 V or 4.75 V to 5.25 V operation - Power dissipation 1 mW maximum @ 3 V - Standby current 8 μA maximum