ADG2188 usage

Question

Hello, 
 I am planning to use ADG2188B device for video selection. 
 My requirement is as below. 
 I have 6 composite video inputs with SD-PAL/NTSC standard. I want to select any 2 videos based on my internal logic. 
 So I will connect X0 to X5 to input video sources. I will take the output from Y0 and Y2 to video decoder adv7182. 
 Again, I want to have the processed PAL/NTSC video to be duplicated from the board at the output. 
 I want to connect the video encoder adv7341 output to X7 and have the duplicated output @ Y5 and Y7. 
 The attached pdf represents the block level approach for my requirement. 
 Can you please suggest me, whether this approach will work fine? 
 
 Even for this approach, can I use single +5V supply or I should use +/-5V? 
 Also, I want to know how much current consumption will be there for this approach. If +/-5V to be used, then I have to select the appropriate inverting regulator for this IC. 
 Also, what should be the connection for unused ports? 
 Waiting for your quick response. 
 With Regards, 
 Hariprasad Bhat

ADIApproved · Accepted Answer

Hi Hariprasad Bhat, 
 ADG2188 is a good choice for your application. It is a bidirectional 8x8 switch array with rows and columns can be configured as either inputs or outputs. The only concern that you may want to take a look at is that the array can be selected one at a time. Y ou may not use X0 to X5 and X7 as the input at the same time. This is further explained at the Serial Interface Section, page 19 of the datasheet . Also, please see Table 7, page 20 for the Address Decode Truth Table of the device. 
 For current consumption, 1uA is the max Idd consumption of the device which is stated on page 5 of the datasheet at Vdd=5V and Vss=-5V. 
 For the unused pins, you may leave it floating so the channel will not add up in crosstalk. 
 Let me know if this helps. 
 Best Regards, 
 May

ADIApproved · Answer

Hi Hariprasad Bhat, 
 The schematic looks okay. Just make sure that VDD and VSS meets the correct supply voltage to ensure normal operation of the ADG2188. 
 Best Regards, 
 May

ADIApproved · Answer

Hi Hariprasad Bhat, 
 Can you please confirm if the input of the ADM8660ARZ will be coming from the on board +5V as well? 
 Looking at the ADM8660 datasheet , on the Specifications Table the Voltage Conversion Efficiency is at 99% to 99.96% without Load. This means that if the input voltage is +5V then the output voltage would be around 4.95% but this is true if no load is present. Please remember that for ADM8660, as the load current increases the output voltage drops significantly as seen on TPC 2 page 5. One question is if the ADM8660 is dedicated only for the -5V Vss of the ADG2188? 
 You might want to check on ADP5073 , it is one of the latest and has a better performance inverting regulator which is also suitable for your design. 
 Best Regards, 
 May

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ADG2188 usage

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