Modern designs utilize advanced process features and proprietary design techniques to achieve similar functionality to the LM339 behavior in modern CMOS processes. In many cases, rail to rail input functionality is also added.

Figure 2-3 "Failsafe " ESD Protection

The "Fail-Safe" inputs do not have the "upper" ESD diodes. ESD protection is provided by Snapback or other ground-based clamps. Due to the lack of the upper ESD clamp, the inputs can be taken above the supply voltage, up to a specified maximum voltage, regardless of the supply voltage. The inputs remain high impedance with no damage during this state.

For "Fail-safe" inputs, depending on the device, the output can have a defined behavior when both of the inputs are above the supply voltage. Some devices can maintain a correct output as long as one of the inputs is still within the valid input voltage range, or default to a known high or low output state. Please consult the data sheet applications section for that device for any mention of the output behavior when the input voltage is above the comparator supply voltage. TI always recommends staying within the specified input range.

Because these inputs lack the upper input clamp, please see the Section 4 section.