AD7822BRU-REEL7

Overview

The AD7822BRU-REEL7 is an 8-bit, single-channel analog-to-digital converter (ADC) from Analog Devices. It features a maximum throughput of 2 MSPS and utilizes a half-flash architecture with a 420 ns conversion time. The device operates on a single supply voltage ranging from 3 V ± 10% to 5 V ± 10%. Key specifications include a Signal-to-(Noise + Distortion) Ratio of 48 dB min, Integral Nonlinearity (INL) of ±0.75 LSB max, and Differential Nonlinearity (DNL) of ±0.75 LSB max. It incorporates an on-chip 2.5 V reference, a track-and-hold amplifier, and a flexible parallel interface.

Feature Summary

• Integrates an on-chip 2.5 V reference and track-and-hold amplifier for simplified system design.
• Features automatic power-down at the end of conversion to minimize power consumption.
• Includes VMID pin capability to adjust analog input span offset for single-supply op amp compatibility.

Applications

• Data acquisition systems
• DSP front ends
• Disk drives
• Mobile communication systems

Procurement Notes

Verify the specific package variant against the datasheet outline dimensions. Confirm that the REEL7 suffix corresponds to the required tape and reel quantity for your manufacturing line. Ensure the B version temperature range meets your operational requirements before finalizing the order.

Selection Notes

Select this component when a single-channel, high-speed 8-bit ADC is required. The AD7822 differs from the AD7825 (4 channels) and AD7829 (8 channels). Verify that the parallel interface logic levels match your microprocessor or DSP system. Consider the VMID pin usage if input signal offsets need adjustment.

Part Context

This part belongs to the AD7822/AD7825/AD7829 family of 3 V/5 V, 2 MSPS, 8-Bit Sampling ADCs. While sharing core performance characteristics like conversion speed and architecture, the AD7822 is distinguished by its single-ended analog input configuration compared to the multi-channel variants in the series.

Replacement Considerations

Direct functional replacements within the same family include the AD7825 (4-channel) and AD7829 (8-channel), provided channel count differences are acceptable. Other versions such as AD7822BNZ or AD7822BR may offer different packaging options but share identical electrical specifications.

FAQ

How does the AD7822 handle power-down?

The AD7822 supports automatic power-down at the end of a conversion. If the CONVST pin is logic low when the EOC signal goes high, the device powers down. A separate PD pin can also be used to manually control power-down mode.

What is the function of the VMID pin?

The VMID pin allows the user to offset the analog input span. By applying a voltage to this pin, the input range can be centered anywhere between AGND and VDD, which helps accommodate system offsets or single-supply op amp limitations.

Can the AD7822 operate standalone without a microprocessor?

Yes, the flexible parallel interface includes an End of Conversion (EOC) pulse. This feature allows the ADC to be used in a standalone manner, where the EOC signal can trigger data latching or interrupts independently.