TLE207X_16 Datasheet, PDF (47/89 Pages) Texas Instruments – EXCALIBUR LOW-NOISE HIGH-SPEED JFET-INPUT OPERATIONAL AMPLIFIERS

TLE207x, TLE207xA
EXCALIBUR LOW-NOISE HIGH-SPEED
JFET-INPUT OPERATIONAL AMPLIFIERS
SLOS181C − FEBRUARY 1997 − REVISED DECEMBER 2009
PARAMETER MEASUREMENT INFORMATION
2 kΩ
V_{CC +}
−
+
V_O
R_S
R_S
V_{CC −}
Figure 3. Noise-Voltage Test Circuit
Ground Shield
V_{CC +}
−
+
V_O
V_{CC −}
Picoammeters
Figure 4. Input-Bias and Offset-
Current Test Circuit
IN −
IN +
C_ic
V_{CC +}
C_id
−
+
V_O
C_ic
V_{CC −}
Figure 5. Internal Input Capacitance
typical values
Typical values presented in this data sheet represent the median (50% point) of device parametric performance.
input bias and offset current
At the picoampere bias current level typical of the TLE207x and TLE207xA, 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 is performed that
measures both the socket leakage and the device input bias current. The two measurements are then
subtracted algebraically to determine the bias current of the device.
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