Overview
The AD7781BRUZ-REEL, produced by Analog Devices Inc., is a 20-bit, pin-programmable, ultralow power sigma-delta analog-to-digital converter (ADC). This device is particularly suited for low-frequency measurement applications, such as those involving bridge sensor systems. It features a low noise instrumentation amplifier and an on-chip digital filter, making it ideal for portable or battery-operated products where low power consumption is critical. The AD7781 operates with a power supply range of 2.7 V to 5.25 V and consumes only 330 μA, with a power-down mode to further extend battery life.
Key Specifications
| Parameter | Value |
|---|---|
| Number of Bits | 20 |
| Sampling Rate | 16.7 sps or 10 Hz |
| Input Type | Differential |
| Input Range | ±5 V or ±39 mV (with gain of 128) |
| Power Supply | 2.7 V to 5.25 V |
| Current Consumption | 330 μA |
| Package Type | 16-lead TSSOP |
| Settling Time | 120 ms (at 16.7 Hz), 300 ms (at 10 Hz) |
| Noise Performance | 44 nV rms (at 10 Hz with gain of 128) |
| Filter Response | Superior dynamic performance at 16.7 Hz, better than -45 dB stop-band attenuation at 10 Hz |
Key Features
- Pin-programmable for ease of use, with dedicated pins controlling all features.
- On-chip PGA with a gain of 1 or 128.
- Simultaneous 50 Hz/60 Hz rejection at both output data rates.
- Low noise instrumentation amplifier and on-chip digital filter.
- Power-down mode to switch off power to the bridge sensor and the AD7781 when not converting.
- On-board clock, eliminating the need for an external clock.
- Supports serial data output with eight status bits appended to each 20-bit conversion for data validity confirmation.
Applications
The AD7781 is designed for low-frequency measurement applications, particularly in systems involving bridge sensors such as load cells, pressure sensors, and strain gauges. Its low power consumption and high precision make it suitable for portable or battery-operated devices. It is also useful in industrial automation, medical devices, and any application requiring high accuracy and low noise in analog-to-digital conversion.
Q & A
- What is the resolution of the AD7781BRUZ-REEL?
The AD7781BRUZ-REEL has a resolution of 20 bits. - What are the available sampling rates for the AD7781?
The AD7781 supports sampling rates of 16.7 Hz and 10 Hz. - What is the power consumption of the AD7781?
The AD7781 consumes 330 μA of current. - What are the input ranges for the AD7781?
The input ranges are ±5 V or ±39 mV with a gain of 128. - Does the AD7781 have a power-down mode?
Yes, the AD7781 has a power-down mode to extend battery life. - What type of package is the AD7781 available in?
The AD7781 is available in a 16-lead TSSOP package. - What is the settling time for the AD7781 at different update rates?
The settling time is 120 ms at 16.7 Hz and 300 ms at 10 Hz. - Does the AD7781 support simultaneous 50 Hz/60 Hz rejection?
Yes, it supports simultaneous 50 Hz/60 Hz rejection at both output data rates. - What is the noise performance of the AD7781?
The AD7781 has an rms noise of 44 nV when the gain is 128 at the 10 Hz update rate. - Is the AD7781 suitable for load cell applications?
Yes, it is particularly useful in load cell applications due to its ability to reject low-frequency mechanical vibrations.
