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Precision Amplifiers Forum
Probem wit OPAx141.
Hi, for all.I am amplifying a simple piezo in a simple inversor and splitting the power line of 5V in +/-2V5 like SLOA058 figure 2.I´ve worked with OPAx141 in +/-10V to +/-12V of power supplies in other circuits, but with +/-2V5 is my the first time.I spend one day fighting with the circuit and now I discover that same circuit works fine in +/-10V of power lines (20V splitted).
In the manual is :"Dual-SupplyOperation:±2.25Vto ±18V"
There is some errata about OPAx141??? What is wrong???I tested two equal prototypes and happend the same behavior!
Although OPA141 works down on +/-2.25V supply voltage, the linear range of the input common-mode voltage is: (V-)-0.1V < Vcm< (V+)-3.5V. Therefore, operating OPA141 on +/-2.5V with the input at the ground potential violates the input voltage range by 1V since at that potential the input voltage is only 2.5V below positive rail (see PDS table below). The OPA141 macro-model available on TI website simulates this problem correctly - please use it for your design needs.
Marek LisSr Application EngineerPrecision Analog - Burr-Brown ProductsTexas Instruments - Tucson
This information is not direct or easy to find on the manual, although on the face of the manual the prevalent information suggest its operation throughout the power range.
This detail escaped me, I was taken for the information of the first page of the manual and I was not thorough.
Furthermore, this device is not rail-to-rail like is in the manual!
Well, I´ll correct it. But do you know some other operatinal that works in full power range?
Thank you very much Merik.
The front page of OPAx141 product data sheet (PDS) makes a claim of only the output being rail-to-rail (please see below):
There are, however, many other op amps in TI portfolio with rail-to-rail input and output. Since you have not provided any details regarding performance required in your specific application, I have shown below just some of them. You may find the full list of the rail-to-rail op amps under the following link:
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