AD7705

PRODUCTION

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

Data Sheet (Rev. C) Product Selection Table
Viewing:

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 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.

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).
AD7705
3V/5V, 1 mW, 2-Channel Differential, 16-Bit Sigma-Delta ADC
AD7705/AD7706 Functional Block Diagram AD7705 Pin Configuration
Add to myAnalog

Add product to the Products section of myAnalog (to receive notifications), to an existing project or to a new project.

Create New Project
Ask a Question

Documentation

Data Sheet 1

Application Note 13

Technical Articles 4

Frequently Asked Question 1

Learn More
Add to myAnalog

Add media to the Resources section of myAnalog, to an existing project or to a new project.

Create New Project

Software Resources

Can't find the software or driver you need?

Request a Driver/Software

Hardware Ecosystem

Parts Product Life Cycle Description
Interface Transceivers & Isolators 9
ADUM4160
PRODUCTION Full/Low Speed USB Digital Isolator
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
ADUM5401
PRODUCTION Quad-Channel, 2.5 kV Isolators with Integrated DC-to-DC Converter (3/1 channel directionality)
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)
ADUM1400
PRODUCTION Quad-Channel Digital Isolator (4/0 Channel Directionality)
ADUM1200
PRODUCTION Dual-Channel Digital Isolator (2/0 Channel Directionality)
Voltage References 6
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
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
Modal heading
Add to myAnalog

Add product to the Products section of myAnalog (to receive notifications), to an existing project or to a new project.

Create New Project

Tools & Simulations

Sigma-Delta ADC Tutorial

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

Open Tool

Evaluation Kits

EVAL-AD7705

AD7705 Evaluation Kit

Buy Now View Details

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.

EVAL-AD7705
AD7705 Evaluation Kit

Latest Discussions

1 Years Ago
AD7705
1 Years Ago
AD7708 - Gain in Calculation Formula
2 Years Ago
Hello everyone, My question is about the use of AD7705 in differential mode configuration. Is it possible to have two simultaneous input signals at the device? In other words, the input signal1+ and signal1- at Ain1+ and Ain1-, respectively. While the inpu
View related discussion on EngineerZone®

Recently Viewed