TLE202X-Q1_15 Datasheet, PDF (33/41 Pages) Texas Instruments – EXCALIBUR HIGH-SPEED LOW-POWER PRECISION OPERATIONAL AMPLIFIERS

TLE202x-Q1, TLE202xA-Q1
EXCALIBUR HIGH-SPEED LOW-POWER PRECISION
OPERATIONAL AMPLIFIERS
SGLS199B − JANUARY 2004 − REVISED APRIL 2008
APPLICATION INFORMATION
voltage-follower applications
The TLE202x circuitry includes input-protection diodes to limit the voltage across the input transistors; however,
no provision is made in the circuit to limit the current if these diodes are forward biased. This condition can occur
when the device is operated in the voltage-follower configuration and driven with a fast, large-signal pulse. It
is recommended that a feedback resistor be used to limit the current to a maximum of 1 mA to prevent
degradation of the device. This feedback resistor forms a pole with the input capacitance of the device. For
feedback resistor values greater than 10 kΩ, this pole degrades the amplifier phase margin. This problem can
be alleviated by adding a capacitor (20 pF to 50 pF) in parallel with the feedback resistor (see Figure 71).
C_F = 20 pF to 50 pF
R_F
−
V_{CC +}
I_F ≤ 1 mA
V_O
V_I
+
V_{CC −}
Figure 71. Voltage Follower
Input offset voltage nulling
The TLE202x series offers external null pins that further reduce the input offset voltage. The circuit in
Figure 72 can be connected as shown if this feature is desired. When external nulling is not needed, the null
pins may be left disconnected.
IN −
IN +
OFFSET N1 ^{5 kΩ}
OFFSET N2
V_CC − (split supply)
1 kΩ GND (single supply)
Figure 72. Input Offset Voltage Null Circuit
• POST OFFICE BOX 655303 DALLAS, TEXAS 75265
33