Overview
The AD7791BRMZ from Analog Devices Inc. is a low-power, 24-bit sigma-delta analog-to-digital converter (ADC) designed for low-frequency measurement applications. This device is part of the AD7790/AD7791 family, which offers a complete analog front end solution. The AD7791 features a single differential input that can be configured as buffered or unbuffered, making it versatile for various measurement needs. It operates from an internal clock, eliminating the need for an external clock source, and supports software-programmable output data rates from 9.5 Hz to 120 Hz.
Key Specifications
| Parameter | Value | Unit | Comments |
|---|---|---|---|
| Number of Bits | 24 | - | Sigma-Delta ADC |
| Number of Channels | 1 | - | Differential Input |
| Sampling Rate | 9.5 Hz to 120 Hz | Hz | Software Programmable |
| Polarity | Bipolar | - | - |
| Interface | SPI, QSPI, MICROWIRE, DSP compatible | - | 3-wire serial interface |
| Min Supply Voltage | 2.5 V | V | - |
| Max Supply Voltage | 5.25 V | V | - |
| Current Consumption (Typical) | 65 µA @ 3V, 75 µA @ 5V | µA | Buffer disabled |
| Power-Down Current | 1 µA | µA | - |
| Package | 10-lead MSOP | - | - |
| Temperature Range | -40°C to +105°C | °C | - |
Key Features
- Low Power Consumption: The AD7791 consumes typically 65 µA of current at 3 V and 75 µA at 5 V, with a power-down mode of 1 µA.
- High Resolution: 24-bit sigma-delta ADC with up to 19.5-bit peak-to-peak resolution and 22 bits effective resolution at lower data rates.
- Internal Clock: Operates from an internal clock oscillator, eliminating the need for an external clock source.
- Buffered or Unbuffered Input: The differential input can be configured as buffered or unbuffered, providing flexibility in measurement setups.
- Simultaneous 50 Hz/60 Hz Rejection: Achieves simultaneous rejection of 50 Hz and 60 Hz noise at certain output data rates.
- Power Supply Monitoring: Includes a VDD monitor channel for power supply monitoring.
- Low Noise: Features low RMS noise of 1.1 µV at 9.5 Hz update rate.
- Serial Interface: 3-wire serial interface compatible with SPI, QSPI, MICROWIRE, and DSP.
Applications
- Smart Transmitters: Suitable for use in smart transmitter applications due to its low power and high accuracy.
- Battery-Powered Devices: Ideal for battery-powered applications because of its ultra-low power consumption.
- Portable Instrumentation: Used in portable instrumentation where low power and high precision are required.
- Sensor Measurement: Applicable in various sensor measurement applications, including temperature, pressure, and weight measurements.
- Weigh Scales: Often used in weigh scale applications due to its high resolution and low noise characteristics.
- 4 to 20 mA Loops: Can be integrated into 4 to 20 mA loop applications for industrial process control.
Q & A
- What is the resolution of the AD7791BRMZ ADC?
The AD7791BRMZ is a 24-bit sigma-delta ADC with up to 19.5-bit peak-to-peak resolution and 22 bits effective resolution at lower data rates.
- What is the typical current consumption of the AD7791BRMZ?
The device typically consumes 65 µA of current at 3 V and 75 µA at 5 V, with a power-down mode of 1 µA.
- Does the AD7791BRMZ require an external clock source?
No, the AD7791BRMZ operates from an internal clock oscillator, eliminating the need for an external clock source.
- What are the supported output data rates for the AD7791BRMZ?
The output data rate is software-programmable and ranges from 9.5 Hz to 120 Hz.
- What types of inputs can the AD7791BRMZ handle?
The AD7791BRMZ has a single differential input that can be configured as buffered or unbuffered.
- What is the temperature range of the AD7791BRMZ?
The device operates over a temperature range of -40°C to +105°C.
- What kind of serial interface does the AD7791BRMZ support?
The AD7791BRMZ supports a 3-wire serial interface compatible with SPI, QSPI, MICROWIRE, and DSP.
- Does the AD7791BRMZ have power supply monitoring capabilities?
Yes, the device includes a VDD monitor channel for power supply monitoring.
- What are some common applications for the AD7791BRMZ?
Common applications include smart transmitters, battery-powered devices, portable instrumentation, sensor measurement, weigh scales, and 4 to 20 mA loops.
- What is the package type of the AD7791BRMZ?
The AD7791BRMZ is housed in a 10-lead MSOP package.
