ADC for HMC760

Hi eugeny,

Although several high speed ADCs offer enhanced sample rates, few of them offer input bandwidth beyond a few GHz. In addition, maintenance of good sampling linearity at frequencies above the UHF band is technologically challenging and most current ADCs suffer rapidly degrading linearity above 1 or 2 GHz signal frequency. These limitations result from the Track-and-Hold Amplifier inside ADCs which sample the input signal at a precise time instant and holds the value of the sample constant during the analog-to-digital conversion. This THA is often not optimized for ultra wideband operation.

These limitations can be overcome by using external wideband Track-and-Hold Amplifier, which is designed for use in microwave data conversion applications requiring maximum sampling rate, low noise and high linearity over a wide bandwidth. They are used as an external master sampler at the front end of an ADC. Once extended bandwidth sampling takes place within the HMC760, the low bandwidth held output waveform can be processed by an ADC with substantially reduced bandwidth. ADC converter linearity limitations at high input frequencies are also mitigated because the settled THA waveform is processed with the optimal low frequency linearity of the ADC.

The result is an extension in input bandwidth, substantial improvement in high frequency linearity and improved high frequency S/N ratio for the THA-ADC assembly compared to the performance of the ADC alone.

Regarding your question, with HMC760 and HMCAD1520 paired, you can sample signals up to 5GHz, with 1000/640/105 MSPS specified by your ADC using correct anti-aliasing filter.

Best Regards

Sinan Alemdar

Hi eugeny,

Although several high speed ADCs offer enhanced sample rates, few of them offer input bandwidth beyond a few GHz. In addition, maintenance of good sampling linearity at frequencies above the UHF band is technologically challenging and most current ADCs suffer rapidly degrading linearity above 1 or 2 GHz signal frequency. These limitations result from the Track-and-Hold Amplifier inside ADCs which sample the input signal at a precise time instant and holds the value of the sample constant during the analog-to-digital conversion. This THA is often not optimized for ultra wideband operation.

These limitations can be overcome by using external wideband Track-and-Hold Amplifier, which is designed for use in microwave data conversion applications requiring maximum sampling rate, low noise and high linearity over a wide bandwidth. They are used as an external master sampler at the front end of an ADC. Once extended bandwidth sampling takes place within the HMC760, the low bandwidth held output waveform can be processed by an ADC with substantially reduced bandwidth. ADC converter linearity limitations at high input frequencies are also mitigated because the settled THA waveform is processed with the optimal low frequency linearity of the ADC.

The result is an extension in input bandwidth, substantial improvement in high frequency linearity and improved high frequency S/N ratio for the THA-ADC assembly compared to the performance of the ADC alone.

Regarding your question, with HMC760 and HMCAD1520 paired, you can sample signals up to 5GHz, with 1000/640/105 MSPS specified by your ADC using correct anti-aliasing filter.

Best Regards

Sinan Alemdar