Inquiries about EXT_CAP of AD5271

Question

Hello, 
 
 For circuit reasons, we are using the AD5271 with a voltage of Vdd:3.300V and Vss:-1.720V. 
 
 We are using only RAM because writing to ROM does not work well, probably due to Vss. 
 I am using RAM only. 
 
 So, please tell me about the following. 
 ・ If the EXT_CAP pin is not used, what potential should it be fixed at? 
 
 If it is used for a charge pump, I think OPEN is better, but what do you think? 
 
 Best Regards, 
 Knj

vsethia · Accepted Answer

even if the ROM is not used, 1uF cap is still needed on EXT_CAP, as during powerup, the device tries to load the registers from the ROM.

vsethia · Answer

No external input needs to be forced on EXT_CAP. 
 Connect a 1 &mu;F capacitor between EXT_CAP and VSS. This capacitor must have a voltage rating of &ge;7 V.

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Inquiries about EXT_CAP of AD5271

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