What happen on voltage level output of DE pin when I set VDD = 1.8V...
Not Recommended for New Designs
The AD9880 offers designers the flexibility of an analog interface and High-Definition Multimedia Interface (HDMI™) receiver integrated on a single chip...
AD9880 on Analog.com
First of all, AD9880 is not recommended for new designs as per AD9880 Datasheet and Product Info | Analog Devices
The replacement part is ADV7842. So we cannot provide support beyond existing documentation and existing EngineerZone posts. If you have an existing platform for AD9880, we suggest you experiment with that and documentation of AD9880 is available at http://www.analog.com/en/products/audio-video/hdmidvi-switches/ad9880.html#product-documentation