ADA4700-1 Single Supply

Question

Dear Experts! 
 
 Can I use ADA4700-1 with an unbalanced supply: +55V/GND? If yes, what should I take care of with this opamp? 
 I basically have a DC input voltage from 0 to 5V and I want to amplify it up to 45 to 55V, no AC signal is expected. 
 
 Thanks and regards, 
 Andras Magyar

maaarmas · Accepted Answer

Hi amagyar377 , 
 Yes, you can use the ADA4700-1 with an unbalanced supply, but you should consider the input and output headroom. Based on the specification table, the input headroom must be around 3V away from the supply and the output should be 1.5 away from the supply.

Hope this information helps. 
 Thanks, 
 Mae)

maaarmas · Answer

Hi Andras, 
 Upon checking the Selection Table for High Voltage Op Amps &ge;12V | Parametric Search | Analog Devices, it seems that we don't have an exact rail to rail amplifiers like you need. In order to have an input of 0-5V and an output of 45-55V, you may need to adjust the supply. 
 
 For example, as seen in the parametric table, the ADA4099 is categorized as rail-to-rail input and output, but looking at the datasheet, the ADA4099 output voltage swing is typically 45mV away from the voltage rail if there's no load. 
 
 Hence, there's still a headroom for output in reference to supply. 
 Is your system flexible with extending the supply rail? 
 Thanks, 
 Mae

maaarmas · Answer

Hi Andras, 
 Based on the given requirements, specifically the input and output, I think LTC2057 is a better fit because the input and output headroom is much closer to the supply. The LTC2057 output voltage swing is typically 0.2mV away from the voltage rail if there's no load, while ADA4099 is typically 45mV. 
 
 But are there any other critical requirements in your application like the short circuit requirement? 
 Regards, 
 Mae

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ADA4700-1 Single Supply

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