AD7705

PRODUCTION

3V/5V, 1 mW, 2-Channel Differential, 16-Bit Sigma-Delta ADC

Data Sheet (Rev. C) Product Selection Table

Part Models: 7
1ku List Price: Starting From $7.47

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Overview

Two Fully Differential Input Channel ADCs
Programmable Gain Front End Gains from 1 to 128
Three-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 max @ 3 V
Standby Current 8 µA max
16-Lead DIP, 16-Lead SOIC and TSSOP Packages

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 programmed 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 V_DD 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.

The AD7705 / AD7706 devices, with a 3 V supply and a 1.225 V reference, can handle unipolar input signal ranges of 0 mV to 10 mV through 0 V to 1.225 V. The devices can accept bipolar input ranges of ±10 mV through ±1.225 V. Therefore, the AD7705 / AD7706 devices perform all signal conditioning and conversion for a 2-channel or 3-channel system.

The AD7705 / AD7706 are ideal for use in smart, microcontroller, or DSP-based systems. The devices feature a serial interface that can be configured for 3-wire operation. Gain settings, signal polarity, and update rate selection can be configured in software using the input serial port. The parts 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 the power-down mode reduces the standby power consumption to 20 μW typ.

These parts are available in a 16-lead, wide body (0.3 inch), plastic dual in-line package (DIP); a 16-lead, wide body (0.3 inch), standard small outline (SOIC) package; and a low profile, 16-lead, thin shrink small outline package (TSSOP).

Part Models: 7
1ku List Price: Starting From $7.47

Documentation

Frequently Asked Question 1

FAQ 03/20/2018

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
AD7705BNZ	16-Lead PDIP	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
AD7705BRUZ	16-Lead TSSOP	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
AD7705BRUZ-REEL	16-Lead TSSOP	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
AD7705BRUZ-REEL7	16-Lead TSSOP	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
AD7705BRZ	16-Lead SOIC Wide	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
AD7705BRZ-REEL	16-Lead SOIC Wide	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
AD7705BRZ-REEL7	16-Lead SOIC Wide	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Jul 21, 2023 - 23_0082 Qualification of Alternate Wafer Fab Site at ADI Limerick for Select ADC Products
		PCN23_0082_Form Material_Report Qualification Results Summary
AD7705BNZ	PRODUCTION
AD7705BRUZ	PRODUCTION
AD7705BRUZ-REEL	PRODUCTION
AD7705BRUZ-REEL7	PRODUCTION
AD7705BRZ	PRODUCTION
AD7705BRZ-REEL	PRODUCTION
AD7705BRZ-REEL7	PRODUCTION
Mar 29, 2021 - 21_0033 Assembly Site Transfer for 14/16L 300_MIL PDIP to Cirtek
		PCN21_0033_Form Material_Report Detailed Change Description Qualification Results Summary
AD7705BNZ	PRODUCTION
Aug 19, 2009 - 07_0024 Package Material Changes for SOT23, MiniSO, MQFP, PDIP, PLCC, SOIC (narrow and wide body), SSOP, TSSOP and TSSOP exposed pad
		Material_Report Material_Report Parts List PCN07_0024_Form Qual Data
AD7705BNZ	PRODUCTION
Jul 1, 2025 - 25_0162 Gold to Copper Wire Conversion
		PCN25_0162_Form Material_Report Qualification Results Summary Qualification Results Summary Qualification Results Summary
AD7705BRUZ	PRODUCTION
AD7705BRUZ-REEL	PRODUCTION
AD7705BRUZ-REEL7	PRODUCTION
Apr 5, 2021 - 21_0035 Amkor Philippines as an Alternate Site for TSSOP_4.4
		PCN21_0035_Form Material_Report Qualification Results Summary Other
AD7705BRUZ	PRODUCTION
AD7705BRUZ-REEL	PRODUCTION
AD7705BRUZ-REEL7	PRODUCTION
Jan 20, 2012 - 11_0218 Halogen Free Material Change for Certain TSSOP Products at Carsem
		PCN11_0218_Form Material_Report Qualification Report Summary
AD7705BRUZ	PRODUCTION
AD7705BRUZ-REEL	PRODUCTION
AD7705BRUZ-REEL7	PRODUCTION
Aug 4, 2010 - 10_0117 Halogen Free Material Change for SOIC_W Products at Carsem
		PCN10_0117_Form Material_Report Reliability Report
AD7705BRZ	PRODUCTION
AD7705BRZ-REEL	PRODUCTION
AD7705BRZ-REEL7	PRODUCTION
Feb 8, 2010 - 04_0080 Qualification of the 8" C6 and Q Wafer Fab Processes at Analog Devices, Limerick, Ireland.
		PCN04_0080_Form Material_Report Reliability Report Reliability Report
AD7705BRZ	PRODUCTION

This is the most up-to-date revision of the Data Sheet.

Software Resources

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Hardware Ecosystem

Parts	Product Life Cycle	Description
Data Isolators 7
ADUM1400	PRODUCTION	Quad-Channel Digital Isolator (4/0 Channel Directionality)
ADUM1200	PRODUCTION	Dual-Channel Digital Isolator (2/0 Channel Directionality)
ADUM7440	PRODUCTION	1 kV RMS Quad-Channel Digital Isolator
ADUM7441	PRODUCTION	1 kV RMS Quad-Channel Digital Isolator

ADUM7442	PRODUCTION	1 kV RMS Quad-Channel Digital Isolator
ADUM5402	PRODUCTION	Quad-Channel, 2.5 kV Isolators with Integrated DC-to-DC Converter (2/2 channel directionality)
ADUM5403	PRODUCTION	Quad-Channel, 2.5 kV Isolators with Integrated DC-to-DC Converter (1/3 channel directionality)
Interface Transceivers 2
ADUM4160	PRODUCTION	Full/Low Speed USB Digital Isolator
ADUM5401	PRODUCTION	Quad-Channel, 2.5 kV Isolators with Integrated DC-to-DC Converter (3/1 channel directionality)
Voltage References 6
AD589	NOT RECOMMENDED FOR NEW DESIGNS	Two-Terminal IC 1.2 V Reference
AD1580	PRODUCTION	1.2 V Micropower, Precision Shunt Voltage Reference
ADR512	PRODUCTION	1.2 V Precision Low Noise Shunt Voltage Reference
AD780	PRODUCTION	2.5 V/3.0 V High Precision Reference
REF43	NOT RECOMMENDED FOR NEW DESIGNS	+2.5V Low Power Precision Voltage Reference
REF192	PRODUCTION	2.5V Precision Micropower, Low Dropout, Low Voltage Reference

Tools & Simulations

Sigma-Delta ADC Tutorial

An interactive illustration showing the behavior of an idealized sigma-delta A/D converter.

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Evaluation Kits

AD7705 Evaluation Kit

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Product Details

The EVAL-AD7705EBZ is a fully featured evaluation Board for the AD7705. The evaluation board can be connected to a PC via the parallel port. Software is provided enabling the user to perform detailed analysis of the ADC's performance.