TL087 Datasheet, PDF (6/20 Pages) Texas Instruments – JFET-INPUT OPERATIONAL AMPLIFIERS

TL087, TL088, TL287, TL288
JFET-INPUT OPERATIONAL AMPLIFIERS
SLOS082A – D2484, MARCH 1979 – REVISED JANUARY 1993
typical values
Typical values as presented in this data sheet represent the median (50% point) of device parametric
performance.
input bias and offset current
At the picoamp bias current level typical of these JFET operational amplifiers, accurate measurement of the bias
current becomes difficult. Not only does this measurement require a picoammeter, but test socket leakages can
easily exceed the actual device bias currents. To accurately measure these small currents, Texas Instruments
uses a two-step process. The socket leakage is measured using picoammeters with bias voltages applied, but
with no device in the socket. The device is then inserted in the socket and a second test that measures both
the socket leakage and the device input bias current is performed. The two measurements are then subtracted
algebraically to determine the bias current of the device.
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