AD7780

PRODUCTION

24-Bit Pin-Programmable Low Power Σ−Δ ADC

Viewing:

Overview

  • Pin-programmable filter response
    Update rate: 10 Hz or 16.7 Hz
  • Pin-programmable in-amp gain
  • Pin-programmable power-down and reset
  • Status function
  • Internal clock oscillator
  • Internal bridge power-down switch
  • Current
    115 μA typical (gain = 1)
    330 μA typical (gain = 128)
  • Please see data sheet for additional features

The AD7780 is a complete low power front-end solution for bridge sensor products, including weigh scales, strain gages, and pressure sensors. It contains a precision, low power, 24-bit sigma-delta (Σ-Δ) ADC; an on-chip, low noise programmable gain amplifier (PGA); and an on-chip oscillator.

Consuming only 330 μA, the AD7780 is particularly suitable for portable or battery-operated products where very low power is required. The AD7780 also has a power-down mode that allows the user to switch off the power to the bridge sensor and power down the AD7780 when not converting, thus increasing the battery life of the product.

For ease of use, all the features of the AD7780 are controlled by dedicated pins. Each time a data read occurs, eight status bits are appended to the 24-bit conversion. These status bits contain a pattern sequence that can be used to confirm the validity of the serial transfer.

The on-chip PGA has a gain of 1 or 128, supporting a full-scale differential input of ±5 V or ±39 mV. The device has two filter response options. The filter response at the 16.7 Hz update rate provides superior dynamic performance. The settling time is 120 ms at this update rate. At the 10 Hz update rate, the filter response provides greater than −45 dB of stop-band attenuation. In load cell applications, this stop-band rejection is useful to reject low frequency mechanical vibrations of the load cell. The settling time is 300 ms at this update rate. Simultaneous 50 Hz/60 Hz rejection occurs at both the 10 Hz and 16.7 Hz update rates.

The AD7780 operates with a power supply from 2.7 V to 5.25 V. It is available in a narrow body, 14-lead SOIC package and a 16-lead TSSOP package.

Applications

  • Weigh scales
  • Pressure Measurement
  • Industrial Process Control
  • Portable instrumentation

AD7780
24-Bit Pin-Programmable Low Power Σ−Δ ADC
AD7780 Functional Block Diagram
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

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


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-AD7780

AD7780 Evaluation Board

Product Details

The EVAL-AD7780EBZ is a fully featured evaluation Board for the AD7780. The evaluation board can be connected to a PC via a standard USB interface. Software is provided enabling the user to perform detailed analysis of the ADC's performance.


Please note: This Evaluation software does not run on Windows 8 or Windows 10 (USB driver is non-compliant with OS >Windows 7).

EVAL-AD7780
AD7780 Evaluation Board

Reference Designs

Weigh Scale System Using the AD7780
CN0107 Circuits from the lab

Weigh Scale Design Using the AD7780 24-Bit Sigma-Delta ADC with Internal PGA

Features and Benefits

  • 24-bit Weigh scale application circuit
  • Integrated PGA allows for wide array of weigh scales
  • Low power and low cost
  • Typically used in portable weigh scale applications
CN0107
Weigh Scale Design Using the AD7780 24-Bit Sigma-Delta ADC with Internal PGA
Weigh Scale System Using the AD7780

Latest Discussions

Recently Viewed