AD8138AR

Overview

The AD8138AR is a low distortion differential amplifier manufactured by Analog Devices Inc. using the proprietary XFCB bipolar process. It features a -3 dB bandwidth of 320 MHz at G = +1 and a slew rate of 1150 V/µs. The device settles to 0.01% in 16 ns with an overdrive recovery time of 4 ns. Input voltage noise is 5 nV/√Hz, and typical offset voltage is 1 mV. Operating range is +3 V to ±5 V with 90 mW power consumption at 5 V. It provides -94 dBc SFDR at 5 MHz and -85 dBc at 20 MHz.

Feature Summary

• Internal feedback architecture ensures balanced output gain and phase matching while suppressing even-order harmonics.
• Adjustable output common-mode voltage via VOCM pin allows level-shifting for single-supply ADC applications.
• Externally adjustable gain minimizes errors associated with external resistor mismatches.

Applications

• ADC drivers
• Single-ended-to-differential converters
• IF and baseband gain blocks
• Differential buffers
• Line drivers

Procurement Notes

Verify the specific package type against the datasheet requirements, as the AD8138 series includes both SOIC and MSOP options. Confirm that the ordering suffix matches the desired physical footprint and lead configuration. Ensure environmental specifications align with the required operating temperature range of -40°C to +85°C before finalizing procurement.

Selection Notes

Select this component when driving high-performance ADCs requiring low harmonic distortion and wide bandwidth. It simplifies design by eliminating transformers for DC preservation. Consider the internal feedback benefits for maintaining balance without tight external component matching. Evaluate power supply constraints against the specified operating range.

Part Context

The AD8138 represents a significant advancement over standard operational amplifiers for differential signal processing. Manufactured on Analog Devices' XFCB bipolar process, it offers superior dynamic performance compared to discrete solutions or older integrated drivers. It serves as a dedicated solution for converting single-ended signals to differential formats efficiently.

Replacement Considerations

AD8138ARZ

FAQ

How does the AD8138 handle output common-mode voltage?

The output common-mode voltage is adjustable via the VOCM pin. An internal feedback loop forces the output common-mode level to match the voltage applied to this pin, allowing precise level-shifting for different ADC input requirements.

What is the mechanism for harmonic suppression in the AD8138?

The device utilizes a unique internal feedback feature that provides balanced output gain and phase matching. This architecture inherently suppresses even-order harmonics, resulting in low distortion performance.