Part Number: LM139
1) We have had recreated a fault where if the common voltage range is taken to outside the Vcc - 2 specification we will get a large input bias current, this is understood to be the failure mode and TI have conformed that.
However, the datasheet states that no damage will occur to the device. We think this is incorrect as we have found once the large bias current occurs there is no way recovering the device (bringing common mode into spec) from this large bias current. Can this be confirmed as error in the datasheet?
2) We are also seeing devices failing for unresponsive outputs. The device has 4 channels. If 2 of these channels were operated at Common mode greater than Vcc-2 would this have an effect to cause failure on channel 3 and 4, which are within the common voltage spec?
3) Power sequencing and input. Is there an increased chance of failure if the signal to the input terminals is present before the voltage rails have stabilised?
TI offers many different versions of the LM139, so I would first like to confirm that we are talking about the same product. My assumption is that you are talking about either the mil grade LM139 or space grade LM139 covered by the LM139AQML datasheet. My answer will be based on that assumption, but please give us your exact part number to confirm the answer is for the correct product.
The datasheet is correct in that taking the inputs negative is not destructive as long as the input currents do not exceed 50 mA as shown in the Abs Max table. You mention large bias currents. Exceding the 50 mA limit could damage the part.
Power sequencing is not an issue as long as you stay within the Abs Max of the datasheet. The voltages applied to the inputs and outputs are inpendent of the supply voltage.
Again, these answers are for those parts covered by the LM139AQML datasheet. If it is another version of the LM139, the answer is completey different.
In reply to Kirby Kruckmeyer96848:
In reply to James Allan:
It can get a bit confusing with the different versions of the LM139. Based on your part number, it looks like you are looking at a different LM139 than Kirby mentioned and it is covered by a completely different datasheet.
Can you confirm if this datasheet is the one you are looking at? This will be the correct datasheet for your part.
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