An extremely common question we get here at DigiKey concerning a very wide variety of products is whether a part can be used at “just a little tiny bit” over its given absolute maximum specifications without issue. As one example, we’ve recently received this question for Texas Instruments’ INA195AIDBVR, which has a listed Absolute maximum reflow temperature of 260 degrees Celsius. A customer asked us if the part could withstand a short exposure to 262 degrees Celsius, instead. How do questions like this normally go, and is there any good rule of thumb for going “just a little tensy bit” beyond a product’s listed maximum specifications?
The rule of thumb for going beyond a product’s maximum specified ratings is “don’t.” The supplier will not ever verify or guarantee usage beyond or above these maximum values, because the maximum values are a maximum for a reason. Beyond the values given in the product’s documentation, the manufacturer will make no claims about what will happen to the device.
Picture a weightlifter who knows he can lift five hundred pounds while straining to his absolute utmost. He lifts his five hundred pounds, and an unscrupulous bystander adds another five pounds to his lift. Is that weightlifter likely to suddenly collapse, drop his weights, and lose the ability to lift? No - but he could easily tear a muscle or suffer another sort of injury from pushing beyond his physical limits. Such an injury could end up catastrophically worsening when he tries to lift again, or it could end up permanently reducing his ability to lift weights such that he cannot ever safely get to five hundred pounds again. Because the injury is relatively small, it could go undiscovered and undiagnosed for potentially quite some time.
Similarly, an electronic component’s absolute maximum ratings are called “Absolute maximum” because that is what the part can handle strained to its utmost without suffering injury. Go above those ratings - even by what seems like an insignificantly small value - and you risk wounding the part in ways that might be very difficult to diagnose later, similar to ESD damage. And unlike our hypothetical weightlifter, your electronic components cannot heal. Once wounded, the component stays that way. You could reduce its working lifetime, reduce its safe operating values, or leave a weakness in the part that will worsen over time into an eventual failure. You might get lucky and avoid damaging the product, but the moment you go beyond those specified limits by any amount for any time? You can no longer be certain the product is not damaged.
If you must go over a product’s absolute maximum ratings for any reason, keep in mind that the product is now an unknown level of damaged and should be treated with due suspicion in the future. Maintenance personnel should be aware of this and ready to replace the component, ideally without going over its maximum ratings, and if your process requires continual exposure to conditions beyond your products’ maximum ratings, you will need to specify new products that can tolerate your conditions.
There is no “safe” way to exceed a product’s absolute maximum ratings.