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 Signal Chain Basics #148: Understanding the impact of offsets in fully differential amplifier circuits 5/29/2019 Image 1 of 7      Next > Figure 1 Click here for larger image FDA differential- and common-mode output signals Image 1 of 7      Next > Return to Article Newest First | Oldest First | Threaded View steve.taranovich 6/3/2019 4:13:58 PM User Rank Blogger Re: More complete output DC offset calculations Here is the link to Michael Steffes' article https://www.planetanalog.com/author.asp?section_id=3404&doc_id=565037&  Reply   Post Message   Messages List   Start a Board Login50%50% jfreet 6/3/2019 1:20:40 PM User Rank Newbie Re: More complete output DC offset calculations Hi Michael,    Yes, excellent point. For this article I chose to focus mainly on the amplifier's intrisic offsets and the source offset, but we definitely shouldn't forget to consider resistor matching as well. Thanks for pointing that out!     Reply   Post Message   Messages List   Start a Board Login50%50% Tucson_Mike 5/31/2019 8:25:02 AM User Rank Blogger More complete output DC offset calculations Hey Jacob,    Good stuff but you left a few error terms out of the discussion. In assembling the THS4551 data sheet, I got into these issues way back in section 8.3.4 where the dominant static (not drift) output DC offset actually arises from the desired output common mode voltage converting to a differential error through the resistor ratio mismatch on the two feedback side. Table 3 summarizes this where assuming worst case 1% resistor divider mismatch gives by far the highest nominal part of the output offset total. However, the next table 4 shows it is a very small part of the drift. The lesson there is if you care about output offset error, put some effort into matching those feedback dividers using better precision on the R's and exactly matching the Rg on each side. There was actually an error in this section in how I treated the conversion of avg input bias current through resistor mismatches - corrected that in a recent FDA DC precision article over on Planet Analog 'DC Precision considerations for high speed current and fully differential amplifiers, Insight #4" Reply   Post Message   Messages List   Start a Board Login50%50% More Blogs from Signal Chain Basics Most people are not familiar with electromechanical spinning. My goal here is to attempt to explain brushless-DC motors simply The latest direct radio frequency (RF)-sampling transceivers provide a number of powerful capabilities that enable advanced system features like multiband and multimode operation, as well as frequency translation and fast frequency hopping. At the heart of a transceiver is usually a phase-locked-loop (PLL) synthesizer, which delivers a signal to downstream components such as mixers, filters and power amplifiers. A transimpedance amplifier (TIA), which takes the current from a photodiode and converts it into a usable voltage with low output impedance, can provide effective gain for a photodiode signal. flash poll All polls follow Planet Analog on Twitter Tweets about "from:PlanetAnalog OR #PlanetAnalog OR @PlanetAnalog" like us on facebook our partners
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