GB4571

The GB4571 is a high performance video buffer with DC restore used primarily for accurate back porch clamping. Key features of GB4571 include operation from ±4.5 V to ±13.2 V supply voltages, fast recovery from sudden changes in DC offset, ±0.1 dB flatness to 80 MHz and availability of industry standard DIP and SOIC packages.

In the typical back porch clamping application, a negative going back porch pulse from an external sync separator (such as the GS4881 or GS4882) is applied to the GB4571'sSTROBE input. While STROBE is low, the GB4571 determines the correct DC level shift that should be applied to the input signal by integrating over the entire back porch period. This reduces sensitivity to noise and improves the accuracy of the DC restoration compared to systems using sample and hold techniques. Typical clamping accuracy of ±1 mV is achieved by the GB4571.