The AD829 is a low noise (1.7 nV/√Hz), high speed op amp with custom compensation that provides the user with gains from ±1 to ±20 while maintaining a bandwidth greater than 50 MHz. The AD829's 0.04° differential phase and 0.02% differential gain performance at 3.58 MHz and 4.43 MHz, driving reverse-terminated 50 ? or 75 ? cables, makes it ideally suited for professional video applications. The AD829 achieves its 230V/μs uncompensated slew rate and 120 MHz gain bandwidth product while requiring only 5 mA of current from the power supplies.

The AD829's external compensation pin gives it exceptional versatility. For example, compensation can be selected to optimize the bandwidth for a given load and power supply voltage. As a gain-of-two line driver, the -3dB bandwidth can be increased to 95 MHz at the expense of 1 dB of peaking. In addition, the AD829's ouput can also be clamped at its external compensation pin.

The AD829 has excellent dc performance. It offers a minimum open-loop gain of 30 V/mV into loads as low as 500 ?, low input voltage noise of 1.7 nV/√Hz, and a low input offset voltage of 1 mV maximum. Common-mode rejection and power supply rejection ratios are both 120 dB.

The AD829 is also useful in multichannel, high speed data conversion where its fast (90 ns to 0.1%) settling time is of importance. In such applicatons, the AD829 serves as an input buffer for 8-to-10-bit A/D converters and as an output I/V converter for high speed D/A converters.

The AD829 provides many of the same advantages that a transimpedance amplifier offers, while operating as a traditional voltage feedback amplifier. A bandwidth greater than 50 MHz can be maintained for a range of gains by changing the external compensation capacitor. The AD829 and the transimpedance amplifier are both unity gain stable and provide similar voltage noise performance (1.7 nV/√Hz). However, the current noise of the AD829 (1.5pA/√Hz) is less than 10% of the noise of transpedance amps. Furthermore, the inputs of the AD829 are symmetrical.