AD7722 CMOS, 16-Bit, 195 kSPS Sigma-Delta ADC

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.

Features and Benefits
  • 16-Bit Σ-Δ ADC
    - 64 x Oversampling Ratio
    - Up to 220 kSPS Output Word Rate
    - Low-Pass, Linear Phase Digital Filter
  • Inherently Monotonic
  • On-Chip 2.5 V Voltage Reference
  • Single-Supply 5 V
  • High Speed Parallel or Serial Interface
Analog to Digital Converters
Data Sheets
Documentnote
AD7722: 16-Bit, 195 kSPS CMOS, Σ-Δ ADC Data Sheet (Rev. B)PDF 447 kB
Application Notes
Documentnote
AN-202: An IC Amplifier User’s Guide to Decoupling, Grounding, and Making Things Go Right for a Change (Rev. B)PDF 76.97 K
AN-389: Using Sigma-Delta Converters-Part 2PDF 590 kB
AN-388: Using Sigma-Delta Converters-Part 1PDF 590 kB
AN-311: How to Reliably Protect CMOS Circuits Against Power Supply OvervoltagingPDF 217 kB
AN-397: Electrically Induced Damage to Standard Linear Integrated Circuits:PDF 149 kB
AN-283: Sigma-Delta ADCs and DACsPDF 1699 kB
Order Information
Part NumberPackagePacking QtyTemp RangePrice 100-499Price 1000+RoHS
AD7722ASZ ProductionPLASTIC QUAL FLATPACK/MQFPOTH 96-40 to 85C22.2618.92Y
Reference Materials
AD7722: 16-Bit, 195 kSPS CMOS, Σ-Δ ADC Data Sheet (Rev. B) ad7722
AN-202: An IC Amplifier User’s Guide to Decoupling, Grounding, and Making Things Go Right for a Change (Rev. B) ad7715
AN-389: Using Sigma-Delta Converters-Part 2 ad7715
AN-388: Using Sigma-Delta Converters-Part 1 ad7715
AN-397: 标准线性集成电路的电诱发损坏 (Rev. 0) ad7715
AN-202: IC放大器用户指南:去耦、接地及其他一些要点 (Rev. 0) ad8021
AN-311: How to Reliably Protect CMOS Circuits Against Power Supply Overvoltaging ad1674
AN-397: Electrically Induced Damage to Standard Linear Integrated Circuits: ad7715
AN-311: 如何切实有效地保护CMOS电路不受电源过压影响 (Rev. 0) adg406
AN-389: 使用Σ-Δ转换器—第二部分[中文版] (Rev. 0) ad7715
AN-388: 使用Σ-Δ转换器—第一部分[中文版] (Rev. 0) ad7715
AN-283: Σ-Δ型ADC和DAC[中文版] (Rev. 0) ad74111
AN-283: Sigma-Delta ADCs and DACs ad7715
MS-2210:高速ADC的电源设计 ad9861
Part 2: Circuit Suggestions Using Features and Functionality of New Sigma-Delta ad7715
Part 1: Circuit Suggestions Using Features and Functionality of New Sigma-Delta ad7715