Overview
The AD7771-4BCPZ, 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, enabling ultralow input current to allow direct sensor connection. Each input channel includes a programmable gain stage with gains of 1, 2, 4, and 8, which helps to maximize the dynamic range of the signal chain by mapping lower amplitude sensor outputs into the full-scale ADC input range. The AD7771 accepts a VREF voltage from 1 V to 3.6 V and supports both unipolar and true bipolar analog input signals, as well as true differential or single-ended signal configurations.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Number of Channels | 8 | - | - | - |
| Resolution | 24-bit | - | - | - |
| VREF Voltage | 1 V | - | 3.6 V | V |
| Analog Supply Voltage (AVDD1x) | 3.0 V | 3.6 V | 3.6 V | V |
| Analog Supply Voltage (AVDD2x) | 2.2 V | - | 3.6 V | V |
| Operating Temperature Range | -40°C | - | +105°C | °C |
| Power Consumption (High Resolution Mode per Channel) | - | 16.6 mW | - | mW |
| Power Consumption (Low Power Mode per Channel) | - | 5.25 mW | - | mW |
| Sample Rate | - | - | 256 kSPS | kSPS |
| Package Type | - | - | 64-Lead LFCSP (9mm x 9mm w/ EP) | - |
Key Features
- Eight full Σ-Δ ADCs on-chip for simultaneous sampling.
- Programmable gain stages with gains of 1, 2, 4, and 8 for each channel.
- Ultralow input current for direct sensor connection.
- Support for unipolar and true bipolar analog input signals.
- Configurable to accept true differential or single-ended signals.
- Includes ADC modulator and sinc3/sinc5, low latency digital filter for each channel.
- Sample rate converter (SRC) for fine resolution control over output data rate (ODR).
- Two modes of operation: high resolution mode and low power mode.
- Internal 2.5 V reference and reference buffer with a typical temperature coefficient of ±10 ppm/°C.
- 12-bit SAR ADC for diagnostics without decommissioning Σ-Δ ADC channels.
- General-purpose input/output pins (GPIOs) for controlling external multiplexers.
Applications
- Industrial automation and control systems.
- Medical devices requiring high precision and low noise.
- Aerospace and defense applications where high reliability is crucial.
- Test and measurement equipment.
- Automotive systems, especially those requiring simultaneous sampling of multiple sensors.
- Functional safety applications where the SAR ADC can validate Σ-Δ ADC measurements.
Q & A
- What is the number of channels supported by the AD7771?
The AD7771 supports 8 channels for simultaneous sampling.
- What are the gain options available for each channel?
Each channel has programmable gain stages with gains of 1, 2, 4, and 8.
- What is the range of VREF voltage accepted by the AD7771?
The AD7771 accepts a VREF voltage from 1 V to 3.6 V.
- What are the operating temperature ranges for the AD7771?
The specified operating temperature range is −40°C to +105°C, although the device is operational up to +125°C.
- How much power does each channel consume in high resolution mode and low power mode?
In high resolution mode, each channel consumes 16.6 mW, and in low power mode, each channel consumes 5.25 mW.
- What is the maximum sample rate of the AD7771?
The maximum sample rate is 256 kSPS.
- What package type is the AD7771 available in?
The AD7771 is available in a 64-Lead LFCSP (9mm x 9mm w/ EP) package.
- Does the AD7771 have an internal reference and reference buffer?
Yes, the AD7771 includes a 2.5 V internal reference and reference buffer.
- What is the purpose of the SAR ADC in the AD7771?
The 12-bit SAR ADC is used for diagnostics without decommissioning one of the Σ-Δ ADC channels dedicated to system measurement functions.
- How can the sample rate converter (SRC) be controlled?
The SRC can be controlled through the serial port interface (SPI) to allow fine resolution control over the output data rate (ODR).
