AD7779ACPZ

Overview

The AD7779ACPZ is an 8-channel, simultaneous sampling analog-to-digital converter featuring 24-bit resolution. It supports output data rates up to 16 kSPS per channel in high-resolution mode and includes a programmable gain amplifier with gains of 1, 2, 4, and 8. The device operates on bipolar (±1.65 V) or unipolar (3.3 V) analog supplies and a digital I/O supply ranging from 1.8 V to 3.6 V. It incorporates a sample rate converter for coherent sampling, a low-latency sinc3 filter, and an internal 2.5 V reference. A dedicated 12-bit SAR ADC provides system diagnostics without decommissioning measurement channels.

Feature Summary

• Eight full sigma-delta ADCs enable simultaneous sampling across all channels.
• Programmable gain amplifiers allow mapping of lower amplitude sensor outputs into the full-scale input range.
• Sample rate converter facilitates fine resolution control over output data rates for line frequency coherency.
• Integrated 12-bit SAR ADC supports functional safety validation and chip diagnostics.

Applications

• Circuit breakers
• General-purpose data acquisition
• Electroencephalography (EEG)
• Industrial process control

Procurement Notes

Verify the specific suffix 'ACPZ' corresponds to the LFCSP-64 package and reel packaging configuration required for your assembly process. Confirm that the operating temperature range meets your environmental specifications, as performance is guaranteed from -40°C to +105°C while functional operation extends to +125°C. Ensure power supply rails match the specified bipolar or unipolar requirements before integration.

Selection Notes

Select this component when simultaneous multi-channel sampling is critical for phase accuracy. Choose the high-resolution mode for applications requiring maximum dynamic range at 16 kSPS, or low-power mode for reduced consumption at lower speeds. Verify that the input signal range aligns with the available PGA settings and reference voltage options to optimize the signal chain dynamic range.

Part Context

The AD7779 belongs to Analog Devices' family of high-performance, multi-channel sigma-delta ADCs designed for precision data acquisition. It shares architectural similarities with other devices in the series but distinguishes itself through its eight-channel simultaneous sampling capability and integrated diagnostic SAR ADC. This positioning makes it suitable for complex industrial and medical systems requiring high channel counts and synchronization.

Replacement Considerations

The AD7770 is a related device within the same product family. Note that the AD7770 lacks the Sample Rate Converter (SRC) feature found in the AD7779, which may impact coherent sampling applications. Verify register compatibility and pinout alignment if substituting between these models.

FAQ

How does the AD7779 handle coherent sampling with line frequency?

The device includes a Sample Rate Converter (SRC) that allows fine resolution control over the output data rate. This enables the ODR to be adjusted to maintain coherency with changes in line frequency, such as tracking 0.01 Hz variations.

What is the purpose of the internal SAR ADC?

The 12-bit SAR ADC is used for system and chip diagnostics. It allows validation of the main sigma-delta ADC measurements without decommissioning any of the eight primary measurement channels, supporting functional safety requirements.

Can the AD7779 accept single-ended inputs?

Yes, the analog inputs can be configured to accept true differential, pseudo-differential, or single-ended signals to match different sensor output configurations.