TLE2227, TLE2227Y, TLE2237, TLE2237Y

EXCALIBUR LOW-NOISE HIGH-SPEED

PRECISION DUAL OPERATIONAL AMPLIFIERS

SLOS184 – FEBRUARY 1997

30

POST OFFICE BOX 655303

APPLICATION INFORMATION

voltage-follower applications

The TLE22x7C 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. A feedback resistor is recommended to limit the current to a maximum of 1 mA to prevent degradation

of the device. Also, this feedback resistor forms a pole with the input capacitance of the device. For feedback

resistor values greater than 10 k

Ω, this pole degrades the amplifier’s phase margin. This problem can be

alleviated by adding a capacitor (20 pF to 50 pF) in parallel with the feedback resistor (see Figure 53).

RF

IF ≤ 1 mA

–

+

VI

VO

VCC –

VCC +

CF = 20 to 50 pF

Figure 53. Voltage-Follower Circuit