TLC2810Z, TLC2810Y

LinCMOS

™ PRECISION

DUAL OPERATIONAL AMPLIFIERS

SLOS120A – AUGUST 1993 – REVISED AUGUST 1994

21

POST OFFICE BOX 655303

APPLICATION INFORMATION

feedback

Operational amplifier circuits nearly always

employ feedback and, since feedback is the first

prerequisite for oscillation, a little 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 34). The value of this

capacitor is optimized empirically.

electrostatic discharge protection

The TLC2810Z incorporates an internal electrostatic discharge (ESD) protection circuit that prevents functional

failures at voltages up to 2000 V as tested under MIL-STD-883C, 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.

latch-up

Because CMOS devices are susceptible to latch-up due to their inherent parasitic thyristors, the TLC2810Z

inputs and outputs are designed to withstand – 100-mA surge currents without sustaining latch-up; however,

techniques should be used to reduce the chance of latch-up whenever possible. Internal protection diodes

should not by design be forward biased. Applied input and output voltages should not exceed the supply voltage

by more than 300 mV. Care should be exercised when using capacitive coupling on pulse generators. Supply

transients should be shunted by the use of decoupling capacitors (0.1

µF typical) located across the supply rails

as close to the device as possible.

The current path established if latch-up occurs is usually between the positive supply rail and ground and can

be triggered by surges on the supply lines and/or voltages on either the output or inputs that exceed the supply

voltage. Once latch-up occurs, the current flow is limited only by the impedance of the power supply and the

forward resistance of the parasitic thyristor and usually results in the destruction of the device. The chance of

latch-up occurring increases with increasing temperature and supply voltages.

–

+

Figure 34. Compensation for Input

Capacitance