New Content (1)
Analog DialogueMaximize the Performance of Your Sigma-Delta ADC Driver
Features and Benefits
- 8-channel, 24-bit simultaneous sampling analog-to-digital converter (ADC)
- Single-ended or true differential inputs
- Programmable gain amplifier (PGA) per channel (gains of 1, 2, 4, and 8)
- Low dc input current
- ±4 nA (differential) and ±8 nA (single-ended)
- Up to 32 kSPS output data rate (ODR) per channel
- Programmable ODRs and bandwidth
- Sample rate converter (SRC) for coherent sampling
- Sampling rate resolution up to 15.2 × 10−6 SPS
- Low latency sinc3 filter path
- Adjustable phase synchronization
- Internal 2.5 V reference
- Two power modes optimizing power dissipation and performance: high resolution mode and low power mode
- Low resolution successive approximation register (SAR) ADC for system and chip diagnostics
- Power supply
- Bipolar (±1.65 V) or unipolar (3.3 V) supplies
- Digital input/output (I/O) supply: 1.8 V to 3.6 V
- Performance temperature range: −40°C to +105°C
- Functional temperature range: −40°C to +125°C
- Combined ac and dc performance
- 103 dB dynamic range at 32 kSPS in high resolution mode
- −109 dB total harmonic distortion (THD)
- ±9 ppm of FSR integral nonlinearity (INL)
- ±15 µV offset error
- ±0.1% FS gain error
- ±10 ppm/°C typical temperature coefficient
The AD7770 is an 8-channel, simultaneous sampling ADC. Eight full sigma-delta (Σ-Δ) ADCs are on chip. The AD7770 provides a low input current to allow direct sensor connection. Each input channel has a programmable gain stage allowing gains of 1, 2, 4, and 8 to map lower amplitude sensor outputs into the full-scale ADC input range, maximizing the dynamic range of the signal chain. The AD7770 accepts a VREF voltage from 1 V up to 3.6 V.
The analog inputs accept unipolar (0 V to VREF) or true bipolar (±VREF/2) analog input signals with 3.3 V or ±1.65 V analog supply voltages, respectively for PGAGAIN = 1. The analog inputs can be configured to accept true differential, pseudo differential, or single-ended signals to match different sensor output configurations.
Each channel contains a PGA, an ADC modulator and a sinc3, low latency digital filter. An SRC is provided to allow fine resolution control over the AD7770 ODR. This control can be used in applications where the ODR resolution is required to maintain coherency with 0.01 Hz changes in the line frequency. The SRC is programmable through the serial port interface (SPI). The AD7770 implements two different interfaces: a data output interface and SPI control interface. The ADC data output interface is dedicated to transmitting the ADC conversion results from the AD7770 to the processor. The SPI writes to and reads from the AD7770 configuration registers and for the control and reading of data from the SAR ADC. The SPI can also be configured to output the Σ-Δ conversion data.
The AD7770 includes a 12-bit SAR ADC. This ADC can be used for AD7770 diagnostics without having to decommission one of the Σ-Δ ADC channels dedicated to system measurement functions. With the use of an external multiplexer, which can be controlled through the three general-purpose input/output pins (GPIOs), and signal conditioning, the SAR ADC can validate the Σ-Δ ADC measurements in applications where functional safety is required. In addition, the AD7770 SAR ADC includes an internal multiplexer to sense internal nodes.
The AD7770 contains a 2.5 V reference and reference buffer. The reference has a typical temperature coefficient of 10 ppm/°C.
The AD7770 offers two modes of operation: high resolution mode and low power mode. High resolution mode provides a higher dynamic range while consuming 10.75 mW per channel; low power mode consumes just 3.37 mW per channel at a reduced dynamic range specification.
The specified operating temperature range is −40°C to +105°C, although the device is operational up to +125°C.
- Protection relays
- General-purpose data acquisition
- Industrial process control
Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (1)
The EVAL-AD7770FMCZ/EVAL-AD7771FMCZ/EVAL-AD7779FMCZ evaluation kit features the AD7770, AD7771, and AD7779 24-bit, analog-to-digital converters (ADCs). The board interfaces with the system demonstration platform SDP-H1 controller board (EVAL-SDP-CH1Z). The SDP-H1 controller board supplies power to the EVAL-AD7770FMCZ/EVAL-AD7771FMCZ/EVAL-AD7779FMCZ evaluation board and also connects to a PC running a Windows® operating system via a USB cable. The AD777x evaluation software fully configures the AD7770, AD7771, and AD7779 device register functionality and provides dc and ac time domain analysis in the form of waveform graphs, histograms, and associated noise analysis for ADC performance evaluation.
The EVAL-AD7770FMCZ/EVAL-AD7771FMCZ/EVAL-AD7779FMCZ evaluation board allows the user to evaluate the features of the ADC. The user PC software executable controls the AD7770, AD7771, and AD7779 over the USB cable through the SDP-H1 controller board.
Full specifications for the AD7770, AD7771, or AD7779 are available in the AD7770, AD7771, or AD7779 data sheets and should be consulted in conjunction with user guide UG-884 when working with the evaluation board.
Features & Benefits
- Full featured evaluation board for the AD7770, AD7771, and AD7779
- PC control in conjunction with the Analog Devices, Inc., SDP, EVAL-SDP-CH1Z
- PC software control and data analysis
- Time and frequency domain
- Standalone hardware capability
Application Notes (4)
Software & Systems Requirements
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.
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.