TLC271_01 Datasheet, PDF (60/82 Pages) Texas Instruments – LinCMOSE PROGRAMMABLE LOW-POWER OPERATIONAL AMPLIFIERS

TLC271, TLC271A, TLC271B
LinCMOS PROGRAMMABLE LOW-POWER
OPERATIONAL AMPLIFIERS
SLOS090D – NOVEMBER 1987 – REVISED MARCH 2001
APPLICATION INFORMATION
feedback
Operational amplifier circuits almost 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 108). The value of this
capacitor is optimized empirically.
ÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏ _VO
Figure 108. Compensation for Input
Capacitance
electrostatic discharge protection
The TLC271 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 TLC271 inputs
and output were designed to withstand – 100-mA surge currents without sustaining latchup; 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 voltage 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.
output characteristics
The output stage of the TLC271 is designed to
sink and source relatively high amounts of current
(see Typical Characteristics). If the output is
subjected to a short-circuit condition, this high
current capability can cause device damage
under certain conditions. Output current capability
increases with supply voltage.
VI ^{ÏÏÏÏÏÏÏÏÏÏÏÏÏÏÏ2.5VÏÏÏÏÏ}
VO
CL
TA = 25°C
f = 1 kHz
VI(PP) = 1 V
– 2.5 V
Figure 109. Test Circuit for Output
Characteristics
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