a CLK_RET output that returns the same clock signal applied to the CLK_VL input, but with timing that mimics the data returning from the I/OVCC inputs. The ISL3034E, ISL3035E, ISL3036E operate at full speed with external input drivers that source as little as 4mA output current. Each I/O channel is pulled up to VCC or VL by an internal 30µA current source, allowing the ISL3034E, ISL3035E, ISL3036E to be driven by either push-pull or open-drain drivers. The ISL3034E and ISL3036E include an enable.