AN-2555 : Why are two amplifier stages needed?

Question

Dear ADI Forum, 
 we want to use LTC6373 to directly drive the LTC2311-16 ADC for a flexible current measurement application for (high performance) motor control. 
 Reading AN-2555, I was surpised to find that two amplifier are used in series. 
 
 Can someone explain the reasoning behind this choice and if it is a bad idea to drive the inputs of LTC2311 directly from LTC6373 
 We sample with up to 2MSPS. 
 Thank you and best regards 
 eyke

NathanT · Accepted Answer

Hi, eyke . 
 
 You can actually use the LTC6373 directly as an Analog-Front-End for the ADC. The reason why in that application note it uses another amplifier, which is the ADA4945, is because of its gain compensation. It was stated in AN-255 the required gain for LTC2387-18. This would mean that it is still case-to-case basis depending on the requirement of the application/ADC. For this, I highly suggest posting another query in (+) Instrumentation Amplifiers - EngineerZone for a more detailed explanation of LTC6373. 
 
 On the other hand, since your application is motor control, here is our ADC, the AD2S1210 Datasheet and Product Info | Analog Devices . You can also check this part for your application. 
 
 Regards, Jo)

Popular Forums

Product Forums

Application Forums

Design Center Forums

Highlighted Webinar

Places

Libraries

Challenge Yourself!

What's Brewing

Places

Resources

Visit ContentZone

The Latest Read

New Release

Recent Technical Insights

Products Mentioned

Associated Drivers

Thread Details

AN-2555 : Why are two amplifier stages needed?

Before You Switch