AD7939BSUZ-REEL7

Overview

The AD7939BSUZ-REEL7 is a high-speed, low-power 10-bit successive approximation register (SAR) analog-to-digital converter manufactured by Analog Devices Inc. It features eight software-configurable analog input channels and operates from a single 2.7 V to 5.25 V supply. The device achieves a maximum throughput rate of 1.5 MSPS with a typical SINAD of 61 dB at a 50 kHz input frequency. It includes an accurate on-chip 2.5 V reference and supports differential, pseudo-differential, or single-ended inputs. The component utilizes a high-speed parallel interface and is available in a 32-lead TQFP package.

Feature Summary

• Eight-channel multiplexed architecture with a programmable channel sequencer for automated sequential conversions.
• Software-selectable analog input configurations supporting single-ended, fully differential, and pseudo-differential modes.
• Integrated precision 2.5 V voltage reference with low temperature coefficient and noise characteristics.
• Flexible power management capabilities including normal operation, autostandby, and full shutdown modes.

Applications

• Industrial process control systems requiring multi-channel data acquisition.
• Portable instrumentation utilizing battery-powered single-supply architectures.
• Medical equipment demanding low-noise signal conversion.
• Automotive sensor interfaces compatible with standard microprocessor logic levels.

Procurement Notes

Verify the specific suffix REEL7 corresponds to tape-and-reel packaging when sourcing components. Confirm that the B version meets the required -40°C to +85°C operating temperature range for your application environment. Ensure compatibility with the 32-lead TQFP footprint during PCB layout planning.

Selection Notes

Select this model over the AD7938 if 10-bit resolution is sufficient, as it offers lower power consumption and higher dynamic performance metrics. Consider the AD7938 if 12-bit accuracy is mandatory for your system requirements. Evaluate the VDRIVE pin configuration to ensure seamless interfacing with either 3 V or 5 V processor systems without level shifting.

Part Context

This component belongs to the AD7938/AD7939 family of high-speed SAR ADCs. It shares the same physical package and pinout as the 12-bit AD7938 variant but provides optimized specifications for 10-bit applications. The series is designed for applications balancing speed, power efficiency, and multi-channel flexibility.

Replacement Considerations

The AD7938BSUZ serves as a direct functional substitute within the same package, offering 12-bit resolution instead of 10-bit. Verify that the increased resolution aligns with your system's accuracy requirements before swapping.

FAQ

How does the VDRIVE pin affect the digital interface?

The VDRIVE pin sets the logic voltage level for the parallel interface, allowing the device to connect directly to 3 V or 5 V processors regardless of the main VDD supply voltage.

What is the function of the CONVST input?

A falling edge on the CONVST input initiates the conversion process and switches the track-and-hold amplifier from track mode to hold mode.

Can the internal reference be overridden?

Yes, the VREFIN/VREFOUT pin can be overdriven by an external reference voltage ranging from 0.1 V to VDD to replace the internal 2.5 V source.