Analog Devices Inc. AD7771BCPZ-RL

The AD7771BCPZ-RL, produced by Analog Devices Inc., is an 8-channel, simultaneous sampling analog-to-digital converter (ADC). This device features eight full Σ-Δ ADCs on-chip, each with an ultralow input current, allowing for direct sensor connection. The AD7771 is designed to maximize the dynamic range of the signal chain by providing programmable gain stages with gains of 1, 2, 4, and 8. It supports both unipolar and true bipolar analog input signals and can be configured to accept true differential or single-ended signals, making it versatile for various sensor output configurations.

• Simultaneous Sampling: All eight channels sample simultaneously, ensuring synchronized data acquisition.
• Programmable Gain Stages: Gains of 1, 2, 4, and 8 to optimize signal chain dynamic range.
• Low Input Current: Allows direct connection to sensors without additional buffering.
• Flexible Input Configuration: Supports true differential and single-ended analog input signals.
• Sample Rate Converter (SRC): Programmable through SPI for fine control over output data rate.
• Dual Operating Modes: High Resolution Mode for higher dynamic range and Low Power Mode for reduced power consumption.
• Integrated SAR ADC: 12-bit SAR ADC for diagnostics and internal node sensing without decommissioning Σ-Δ ADC channels.
• Reference Voltage and Buffer: 2.5 V reference with a typical temperature coefficient of ±10 ppm/°C.

• Industrial Automation: Suitable for precision measurement and control in industrial environments.
• Medical Devices: Used in medical equipment requiring high accuracy and simultaneous sampling of multiple channels.
• Aerospace and Defense: Applies to systems needing robust and precise analog-to-digital conversion.
• Test and Measurement Equipment: Ideal for multichannel data acquisition systems.
• Functional Safety Applications: The integrated SAR ADC can validate Σ-Δ ADC measurements, ensuring functional safety.

1. What is the number of channels in the AD7771BCPZ-RL?

   The AD7771BCPZ-RL has 8 channels.

2. What types of analog input signals does the AD7771 support?

   The AD7771 supports unipolar (0 V to VREF) and true bipolar (±VREF/2 V) analog input signals.

3. What are the programmable gain options for each channel?

   The programmable gain options are 1, 2, 4, and 8.

4. How is the sample rate converter (SRC) controlled?

   The SRC is programmable through the serial port interface (SPI).

5. What are the two operating modes of the AD7771?

   The two operating modes are High Resolution Mode and Low Power Mode.

6. What is the power consumption per channel in High Resolution Mode and Low Power Mode?

   In High Resolution Mode, it consumes 16.6 mW per channel, and in Low Power Mode, it consumes 5.25 mW per channel.

7. What is the operating temperature range of the AD7771?

   The specified operating temperature range is −40°C to +105°C, although it is operational up to +125°C.

8. What type of package does the AD7771BCPZ-RL come in?

   The AD7771BCPZ-RL comes in a 64-Lead LFCSP (9mm x 9mm w/ EP) package.

9. What is the purpose of the integrated SAR ADC?

   The integrated 12-bit SAR ADC is used for diagnostics and internal node sensing without decommissioning one of the Σ-Δ ADC channels.

10. How can the AD7771 be used in functional safety applications?

    The SAR ADC can validate the Σ-Δ ADC measurements in applications where functional safety is required, using an external multiplexer and signal conditioning.