OPA4191IPWT datasheet(25/65 Pages) TI2

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8.3.3 Phase Reversal Protection

The OPAx191 family has internal phase-reversal protection. Many op amps exhibit phase reversal when the

input is driven beyond the linear common-mode range. This condition is most often encountered in noninverting

circuits when the input is driven beyond the specified common-mode voltage range, causing the output to

reverse into the opposite rail. The OPAx191 is a rail-to-rail input op amp, and therefore the common-mode range

can extend up to the rails. Input signals beyond the rails do not cause phase reversal; instead, the output limits

into the appropriate rail. This performance is shown in Figure 8-4.

Time (35 ms/div)

C017

OUT

Figure 8-4. No Phase Reversal

8.3.4 Thermal Protection

The internal power dissipation of any amplifier causes the internal (junction) temperature to rise. This

phenomenon is called self heating. The OPAx191 has a thermal protection feature that prevents damage from

self heating.

This thermal protection works by monitoring the temperature of the output stage and turning off the op

amp output drive for temperatures above approximately 180°C. Thermal protection forces the output to a

high-impedance state. The OPAx191 is also designed with approximately 30°C of thermal hysteresis. Thermal

hysteresis prevents the output stage from cycling in and out of the high-impedance state. The OPAx191 returns

to normal operation when the output stage temperature falls below approximately 150°C.

The absolute maximum junction temperature of the OPAx191 is 150°C. Exceeding the limits shown in Section

6.1 may cause damage to the device. Thermal protection triggers at 180°C because of unit-to-unit variance,

but does not interfere with device operation up to the absolute maximum ratings. This thermal protection is not

designed to prevent this device from exceeding absolute maximum ratings, but rather from excessive thermal

overload.

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OPA191, OPA2191, OPA4191

SBOS701D – DECEMBER 2015 – REVISED AUGUST 2021

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OPA4191IPWT Datasheet(PDF) 25 Page - Texas Instruments