AD7768BSTZ

Overview

The AD7768BSTZ is an 8-channel, 24-bit simultaneous sampling sigma-delta analog-to-digital converter (ADC) housed in a 64-lead LQFP package. It supports a maximum output data rate of 256 kSPS per channel with a 110.8 kHz input bandwidth and achieves 108 dB dynamic range. The device features selectable power modes: Fast (51.5 mW/channel), Median (27.5 mW/channel), and Eco (9.375 mW/channel). It operates with AVDD1 at 5.0 V, AVDD2 from 2.25 V to 5.0 V, and IOVDD from 2.5 V to 3.3 V or 1.8 V. Key performance metrics include ±2 ppm INL, ±50 µV offset error, and ±30 ppm gain error.

Feature Summary

• Simultaneous sampling across eight channels with independent sigma-delta modulators and digital filters for synchronized ac and dc signal acquisition.
• Configurable power scaling allowing trade-offs between input bandwidth, output data rate, and power dissipation via three distinct operating modes.
• Advanced digital filtering options including a wideband linear phase filter with low pass-band ripple and a low-latency sinc5 filter for flexible noise and bandwidth optimization.
• Embedded analog precharge buffers on each analog input and reference terminal to reduce input current and minimize glitches.

Applications

• Data acquisition systems utilizing USB, PXI, or Ethernet interfaces
• Instrumentation and industrial control loops requiring high precision
• Audio test and measurement equipment
• Vibration and asset condition monitoring systems
• High precision medical electroencephalogram (EEG) and electrocardiogram (ECG) recording

Procurement Notes

Verify the specific ordering suffix against the manufacturer's official documentation to ensure correct packaging and temperature grade. Confirm that the required voltage levels for AVDD1, AVDD2, and IOVDD match the system design constraints before procurement. Ensure compatibility with the external reference voltage requirements specified in the datasheet.

Selection Notes

Select this component when simultaneous multi-channel synchronization is critical for the application. Evaluate the power mode requirements based on the necessary input bandwidth and noise performance targets. Consider the available decimation rates and filter types to optimize the dynamic range for specific signal frequencies. Verify that the SPI interface timing meets the host controller capabilities.

Part Context

The AD7768BSTZ belongs to the AD7768 family of high-performance sigma-delta ADCs. It serves as the 8-channel variant within a series that includes single-channel and 4-channel versions like the AD7768-1 and AD7768-4. This family establishes a reusable platform for both low-power DC and high-performance AC measurement modules in industrial and medical applications.

Replacement Considerations

The AD7768-4 is a 4-channel version of the same architecture. The AD7768-1 is the single-channel variant. Substitution requires verifying pinout compatibility and register configuration equivalence, as channel count differences may impact PCB layout and software initialization sequences.