CMOS devices are susceptible to latch-up due to inherent parasitic thyristors. With this in mind, the TLC27Lx inputs and output are designed to withstand −100mA surge currents without sustaining latch-up. However, use best practices to reduce the chance of latch-up whenever possible. Do not forward bias internal-protection diodes. Do not exceed the supply voltage by more than 300mV for applied input and output voltages. Exercise care when using capacitive coupling on pulse generators. Shunt supply transients by using decoupling capacitors (0.1µF typical) located across the supply rails as close to the device as possible.

The current path established if latch-up occurs is typically between the positive supply rail and ground, and is triggered by surges on the supply lines, voltages on either the output or inputs that exceed the supply voltage, or both. After 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 typically results in the destruction of the device. The chance of latch-up occurring increases with increasing temperature and supply voltages.