PRECISION_INCREASING_BUFFER

Published:2009/7/9 22:01:00 Author:May | From:SeekIC

Adding an unity-gain buffer to your analog circuit can increase its precision. For example, by itself, the op amp IC1 exhibits a maximum dVOS/dT of 1.8 μA/℃ and can drive a 600-Ω load. Under thes, conditions, IC1 would dissipate 94 mW incrementally. Thus, the op amp's OJA of 150℃/W would change its VOS by 25μV. The buffer, IC2, will isolate IC1 from the load and eliminate the change in power dissipation in IC1, thereby achieving 1C1's minimum, rated offset-voltage drive. The loop gain of IC1 essentially eliminates the offset of the buffer. Almost any unity-gain buffer will work, provided that it exhibits a 3-dB bandwidth that is at least 5 times the gain-bandwidth product of the op amp.



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