The AD9101 is an extremely accurate, general purpose, high speed sampling amplifier. Its fast and accurate acquisition speed allows for a wide range of frequency vs. resolution performance. The AD9101 is capable of 8 to 12 bits of accuracy at clock rates of 125 MSPS or 50 MSPS, respectively. This level of performance makes it an ideal driver for almost all 8- to 12-bit A/D encoders on the market today.
In effect, the AD9101 is a track-and-hold with a post amplifier. This configuration allows the front end sampler to operate at relatively low signal amplitudes. This results in dramatic improvement in both track and hold mode distortion while keeping power low.
The gain-of-four output amplifier has been optimized for fast and accurate large signal step settling characteristics even when heavily loaded. This amplifier's fast Settling Time Linearity (STL) characteristic causes the amplifier to be transparent to the low signal level distortion of the sampler. When sampled, output distortion levels reflect only the distortion performance of the sampler.
Dramatic SNR and distortion improvements can be realized when using the AD9101 with high speed flash converters. Flash converters generally have excellent linearity at dc and low frequencies. However, as signal slew rate increases, their performance degrades due to the internal comparators' aperture delay variations and finite gain bandwidth product.
The benefits of using a track-and-hold ahead of a flash converter have been well known for many years. However, before the AD9101, there was no track-and-hold amplifier with sufficient bandwidth and linearity to markedly increase the dynamic performance of such flashes as the AD9002, AD9012, AD9020, and AD9060.
A new application made possible by the AD9101 is direct IF-to-digital conversion. Utilizing the Nyquist principle, the IF frequency can be rejected, and the baseband signal can be recovered. As an example, a 40 MHz IF is modulated by a 10 MHz bandwidth signal. By sampling at 25 MSPS, the signal of interest is detected.
The AD9101 is offered in commercial and military temperature ranges. Commercial versions include the AD9101AR in plastic SOIC and AD9101AE in ceramic LCC. Military devices are available in ceramic LCC. Contact the factory for availability of versions in DIP and/or military versions.
