AD8628ARZ

Overview

The AD8628ARZ is a single-channel, zero-drift operational amplifier featuring rail-to-rail input and output capabilities. It operates on a single supply from 2.7 V to 5 V or dual supplies of ±1.35 V to ±2.5 V. Key electrical specifications include a maximum offset voltage of 1 µV, an input bias current of 100 pA, and a gain-bandwidth product of 2.5 MHz at 5 V. The device provides a slew rate of 1 V/µs, a power supply rejection ratio of 130 dB, and a common-mode rejection ratio of 140 dB. It consumes 1.0 mA of supply current and functions within an extended industrial temperature range of -40°C to +125°C.

Feature Summary

• Combines auto-zeroing and chopping techniques to eliminate 1/f noise and minimize offset drift over temperature.
• Provides rail-to-rail input and output swing to maximize signal-to-noise ratio without complex biasing.
• Features extremely low input bias current and ultralow offset voltage for high-precision measurements.
• Delivers fast overload recovery time due to internal settling occurring within two clock cycles.

Applications

• Automotive sensors
• Pressure and position sensors
• Strain gage amplifiers
• Medical instrumentation
• Thermocouple amplifiers

Procurement Notes

Verify the specific package variant (SOIC-8) against the datasheet ordering guide to ensure correct marking codes and packing options. Confirm RoHS compliance status as indicated by the 'Z' suffix in the part number. Check for automotive qualification requirements if the application demands controlled manufacturing standards, as commercial and automotive grades may have differing specifications.

Selection Notes

Select this component when system accuracy requires minimal offset voltage and drift without external trimming. The rail-to-rail architecture simplifies circuit design by allowing full dynamic range usage. Ensure the supply voltage remains within the specified 2.7 V to 5 V range for optimal performance. Consider the 2.5 MHz bandwidth for applications requiring moderate speed with high DC precision.

Part Context

The AD8628ARZ belongs to the AD8628/AD8629/AD8630 family of zero-drift amplifiers manufactured by Analog Devices. This series utilizes a patented ping-pong arrangement of auto-zeroing and chopping to achieve superior noise performance compared to traditional chopper-stabilized amplifiers. The AD8628 specifically denotes the single-channel version available in various plastic packages including SOIC and SOT-23.

Replacement Considerations

Direct substitutes within the same family include the AD8629ARZ (dual channel) and AD8630ARZ (quad channel), which share identical electrical characteristics but differ in channel count. Automotive qualified versions such as the AD8628WARZ offer similar performance with controlled manufacturing for automotive reliability requirements.

FAQ

Does the AD8628ARZ require external components for its auto-zero function?

No, the AD8628ARZ does not require any external capacitors or components to operate its auto-zeroing and chopping topology.

What is the typical overload recovery time for this amplifier?

The overload recovery time is less than 10 µs, as internal settling occurs within two clock cycles after output saturation.

How does the AD8628ARZ handle 1/f noise?

The amplifier internally eliminates 1/f noise through its auto-zeroing mechanism, which corrects slowly varying offsets, thereby reducing output errors in DC-coupled measurements.