CM2009

CM2009 VGA Port Companion Circuit Product Description The CM2009 connects between a video graphics controller embedded in a PC, graphics adapter card or set top box and the VGA or DVI−I port connector. The CM2009 incorporates ESD protection for all signals, level shifting for the DDC signals and buffering for the SYNC signals. ESD protection for the video, DDC and SYNC lines is implemented with low−capacitance current steering diodes. All ESD diodes are designed to safely handle the high current spikes specified by IEC−61000−4−2 Level 4 (±8 kV contact discharge if CBYP is present, ±4 kV if not). The ESD protection for the DDC signal pins are designed to prevent “back current” when the device is powered down while connected to a monitor that is powered up. Separate positive supply rails are provided for the VIDEO, DDC and SYNC channels to facilitate interfacing with low voltage video controller ICs to provide design flexibility in multi−supply−voltage environments. Two non−inverting drivers provide buffering for the HSYNC and VSYNC signals from the video controller IC (SYNC1, SYNC2). These buffers accept TTL input levels and convert them to CMOS output levels that swing between Ground and VCC_SYNC, which is typically 5 V. Additionally, each driver has a series termination resistor (RT) connected to the SYNC_OUT pin, eliminating the external termination resistors typically required for the HSYNC and VSYNC lines of the video cable. There are three versions with different value...