AD7782BRUZ

Overview

The AD7782BRUZ is a read-only, pin-configured 24-bit sigma-delta analog-to-digital converter (ADC) manufactured by Analog Devices Inc. It features two fully differential analog input channels with an on-chip programmable gain amplifier (PGA). The device operates from a single 3 V or 5 V supply and utilizes a fixed update rate of 19.79 Hz, providing simultaneous 50 Hz and 60 Hz rejection. Input ranges are selectable via external pins to ±160 mV or ±2.56 V. The serial interface supports master or slave modes using SPI, QSPI, Microwire, or DSP-compatible protocols. It is housed in a 16-lead TSSOP package.

Feature Summary

• Pin-configurable architecture eliminates the need for programmable registers, simplifying system integration.
• Dual fully differential input channels allow flexible sensor interfacing with rail-to-rail buffering.
• Integrated digital filter provides high common-mode rejection and simultaneous attenuation at power line frequencies.
• Low-power operation includes a dedicated standby mode accessible via chip select control.

Applications

• Sensor measurement systems
• Industrial process control instrumentation
• Weigh scale applications

Procurement Notes

Verify component authenticity through authorized distribution channels. Confirm that the specific ordering suffix matches the required packaging format, such as tube or reel variants. Ensure compatibility with RoHS compliance standards relevant to the target manufacturing region before finalizing procurement orders.

Selection Notes

Select this component when designing low-frequency measurement circuits requiring high resolution without complex register programming. Verify that the application environment remains within the specified operating temperature range of -40°C to +85°C. Ensure the external reference voltage source meets the stability requirements for the desired input range configuration.

Part Context

This device belongs to the AD778x family of precision ADCs designed for weigh scales and industrial sensors. Unlike other members such as the AD7783, which integrates current sources and offers a single channel, the AD7782 focuses on dual-channel voltage measurement capabilities. It shares the same low-power sigma-delta architecture and pinout style found across the series.

Replacement Considerations

The AD7783 serves as a related alternative within the same product family. Designers should note that the AD7783 provides only one differential input channel but includes integrated current sources, whereas the AD7782 offers two channels without internal current sources.

FAQ

How is the input channel selected on the AD7782?

Channel selection is performed via the CH1/CH2 logic pin. A low state selects Channel 1 (AIN1+/AIN1-), while a high state selects Channel 2 (AIN2+/AIN2-).

What crystal frequency is required for operation?

The device requires a 32.768 kHz watch crystal connected to the XTAL1 and XTAL2 pins to generate the internal clock and set the fixed output data rate.

Can the AD7782 operate without a microcontroller?

Yes, the device supports a master mode where it generates its own serial clock (SCLK), allowing it to interface directly with systems that do not provide a clock signal.