AD7781CRZ-REEL

Overview

The AD7781CRZ-REEL is a 20-bit, pin-programmable, low-power Sigma-Delta analog-to-digital converter manufactured by Analog Devices Inc. It features an internal programmable gain amplifier (PGA) with selectable gains of 1 or 128 and an internal clock oscillator. The device operates on a power supply ranging from 2.7 V to 5.25 V for both analog and digital domains. It offers two filter update rates: 10 Hz and 16.7 Hz. Key electrical parameters include a full-scale error of ±0.25% FS, integral nonlinearity of ±6 ppm FSR, and typical current consumption of 330 μA at gain 128. The component is housed in a 14-lead narrow body SOIC package.

Feature Summary

• Pin-programmable architecture allows direct configuration of filter response, PGA gain, and power-down modes without software control.
• Integrated bridge power-down switch enables direct disconnection of external sensors to minimize system power consumption.
• Simultaneous 50 Hz/60 Hz rejection capability ensures effective noise suppression in industrial environments.
• Independent interface power supply supports flexible logic level interfacing between the ADC and microcontrollers.

Applications

• Weigh scales
• Pressure measurement systems
• Industrial process control instrumentation

Procurement Notes

Verify the specific ordering suffix against official documentation to confirm package type and reel specifications. Confirm that the component meets all required environmental and regulatory standards for the intended deployment environment before finalizing procurement decisions.

Selection Notes

Select this component when designing applications requiring high-resolution data acquisition with minimal external support circuitry. Ensure the application benefits from the integrated PGA and internal clock to reduce board space and design complexity compared to discrete solutions.

Part Context

This part belongs to the AD7781 series of precision analog-to-digital converters designed specifically for bridge sensor applications. The CRZ suffix indicates the commercial temperature grade and the specific 14-lead SOIC packaging format used for surface-mount assembly.

Replacement Considerations

The AD7781BRUZ is a verified alternative within the same family offering identical functionality in a 16-lead TSSOP package. Verify pin compatibility and thermal requirements when substituting packages.

FAQ

How is the gain of the AD7781 configured?

The gain is set via the dedicated GAIN pin. A low logic level selects a gain of 128, while a high logic level selects a gain of 1.

What is the function of the BPDSW pin?

The BPDSW pin controls an internal bridge power-down switch. When active, it connects the load cell to ground; when inactive, it disconnects the sensor to save power.

Does the AD7781 require an external clock source?

No, the AD7781 includes an internal clock oscillator, eliminating the need for external timing components.