TLE208X_16 Datasheet, PDF (44/79 Pages) Texas Instruments – EXCALIBUR HIGH-SPEED JFET-INPUT OPERATIONAL AMPLIFIERS

TLE208x, TLE208xA, TLE208xY
EXCALIBUR HIGH-SPEED JFET-INPUT
OPERATIONAL AMPLIFIERS
SLOS182B – FEBRUARY 1997 – REVISED JUNE 2001
PARAMETER MEASUREMENT INFORMATION
2 kΩ
10 kΩ
2 kΩ
VI
VCC ₊
–
+
VCC ₊
VO
RL
CL^†
100 Ω
VI
VCC ₊
–
+
VCC ₊
RL
VO
CL^†
† _{Includes fixture capacitance}
Figure 1. Slew-Rate Test Circuit
† _{Includes fixture capacitance}
2 kΩ
VCC ₊
–
+
VO
RS
RS _{VCC –}
† _{Includes fixture capacitance}
Figure 2. Unity-Gain Bandwidth
and Phase-Margin Test Circuit
Ground Shield
VCC ₊
–
+
VO
VCC _–
Picoammeters
Figure 3. Noise-Voltage Test Circuit
Figure 4. Input-Bias and Offset-
Current Test Circuit
IN –
IN +
Cic
VCC ₊
Cid
–
+
VO
Cic VCC _–
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 TLE208x and TLE208xA, accurate measurement of the bias
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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