The ideal choice for ADC drivers: low-noise fully differential op-amp GX8138, compatible with AD8138

Compared to general-purpose operational amplifiers, the GX8138 has made significant advancements in differential signal processing. The GX8138 can function as both a single-ended-to-differential amplifier and a differential-to-differential amplifier, offering the same ease of use as a general-purpose operational amplifier while greatly simplifying differential signal amplification and driving.

The GX8138 offers excellent distortion performance, making it an ideal driver for ADCs in communication systems, capable of driving 10-bit to 16-bit converters at higher frequencies. Its high bandwidth and IP3 characteristics make it suitable for use as a gain module in intermediate frequency (IF) and baseband signal chains. Its outstanding offset and dynamic performance make it highly suitable for various signal processing and data acquisition applications. The GX8138 is available in SOIC and MSOP packages, with an operating temperature range of -40°C to +125°C.

The GX8138 fully differential operational amplifier features low noise, high bandwidth, high slew rate, and rail-to-rail output characteristics. It is primarily used in applications such as ADC drivers, single-ended/differential conversion, intermediate frequency and baseband gain modules, differential buffers, and line drivers. The GX8138 fully differential operational amplifier also features adjustable output common-mode voltage and fully differential complementary outputs. Compared to general-purpose operational amplifiers, fully differential


operational amplifiers have the following three main advantages:

1. Suppression of common-mode interference

2. Suppression of even-order harmonics, providing better linearity

3. Increased dynamic range

In addition, the GX8138 offers high-voltage, high-bandwidth performance: it supports dual-supply voltages of ±5V and single-supply voltages of 10V, with an output voltage swing of 9.7VPP near the supply rails and a -3dB bandwidth of 315MHz. Therefore, in addition to being used with the SC2245, it can also drive other 10-bit to 16-bit converters at higher frequencies.

The GX8138‘s high-bandwidth characteristics enable it to maintain high flatness across a wide frequency range, making it suitable for use as a gain module in intermediate frequency (IF) and baseband signal chains. The common-mode feedback loop forces the signal components in the common-mode voltage to zero, resulting in nearly perfect differential output: equal amplitude, with a phase difference of 180°. In short, the GX8138 is the ideal choice for ADC drivers.