How to connect ADV8005 PIN N23/W23

Question

Hi 
 Base on ADV8005_PRA, N23/W23 should connect to 1.8V, 
 But from the reference design(SCH and PCB),these two Pins no connection. 
 How to connect these two Pins? 
 On my board, I connect these 2 pins to 1.8v 
 Now I meet a issue, TX 4K output not worked (TX Pll not locked, even for PVSP 4K freerun), but 4K input works well (for example 4K to 1080P) 
 I already checked and improve the power ripple 
 I wonder if the issue related with these 2 pins connection 
 Thanks 
 Tommy

mattp · Accepted Answer

Hi Tommy, 
 According to the ADV8005 datasheet: 
 * N23 is AVDD3 and should be connected to 1.8V 
 * W23 is AVDD4 and should be connected to 1.8V 
 Regarding our schematic for EVAL-ADV8005-SMZ, it is a little confusing because we are still using a PCB we originally designed for ADV8003. On that board, N23 and W23 are shorted together and connected to 3.3V through a Do Not Populate resistor. Even this connection was left over from ADV8002, and not needed for ADV8003. For ADV8003, N23 should be No Connect and W23 should be No Connect. 
 Our ADV8003 board with N23 shorted to W23 but left floating otherwise seems to work okay for ADV8005 but I would not recommend this configuration. I would recommend sticking with the configuration shown in the ADV8005 datasheet. 
 We plan to design a new PCB for ADV8005 in 2015. 
 -Matt)

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How to connect ADV8005 PIN N23/W23