–

+

Figure 42. Compensation for Input Capacitance

TLV2332, TLV2332Y, TLV2334, TLV2334Y

LinCMOS

™ LOW-VOLTAGE MEDIUM-POWER

OPERATIONAL AMPLIFIERS

SLOS189 – FEBRUARY 1997

26

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

APPLICATION INFORMATION

input characteristics (continued)

It is good practice to include guard rings around inputs (similar to those of Figure 37 in the Parameter

Measurement Information section). These guards should be driven from a low-impedance source at the same

voltage level as the common-mode input (see Figure 41).

The inputs of any unused amplifiers should be tied to ground to avoid possible oscillation.

–

+

–

+

–

+

VO

VI

VI

VO

VI

VO

(a) NONINVERTING AMPLIFIER

(b) INVERTING AMPLIFIER

(c) UNITY-GAIN AMPLIFIER

Figure 41. Guard-Ring Schemes

noise performance

The noise specifications in operational amplifiers circuits are greatly dependent on the current in the first-stage

differential amplifier. The low input bias-current requirements of the TLV233x results in a very low noise current,

which is insignificant in most applications. This feature makes the device especially favorable over bipolar

devices when using values of circuit impedance greater than 50 k

Ω, since bipolar devices exhibit greater noise

currents.

feedback

Operational amplifiers circuits nearly always

employ feedback, and since feedback is the first

prerequisite for oscillation, caution is appropriate.

Most oscillation problems result from driving

capacitive

loads

and

ignoring

stray

input

capacitance. A small-value capacitor connected

in parallel with the feedback resistor is an effective

remedy (see Figure 42). The value of this

capacitor is optimized empirically.

electrostatic-discharge protection

The TLV233x incorporates an internal electrostatic-discharge (ESD)-protection circuit that prevents functional

failures at voltages up to 2000 V as tested under MIL-PRF-38535. Method 3015.2. Care should be exercised,

however, when handling these devices as exposure to ESD may result in the degradation of the device

parametric performance. The protection circuit also causes the input bias currents to be temperature dependent

and have the characteristics of a reverse-biased diode.