Hi
There are two versions of marking, old marking is with printing, new version is without printing, the same use environment, without printing parts: no matter how the sampling pin is changed, the pin is always output high level without change. May I ask whether there is any difference in the function of this two versions of marking
Hello Yingjiao,
As Clemens asked, is the voltage on pin pin 3 really 5V? Is the input on pin 2 really 3 or 6.5V?
The LM2903 family is under PCN to change the die. You seem to have received a batch with the new die.
The input range is Vcc-2V, or 3V on a 5V supply. The new die has a different behavior when BOTH inputs are above the specified input range (>3V).
You will see the difference when BOTH inputs are above 3V. In summary, the old die output went low during this time, and the "new" die goes high.
Please see sections 2.5, 2.3 and 2.4, in that order, in the LM339 family appnote. This is all explained there:
Application Design Guidelines for LM339, LM393, TL331 Family Comparators
In short, you have to make sure ALL the input voltages are below 3V for proper operation.
An alternative would be to use the TLV3402, which has a fail-safe R-R input that can take inputs up to 10V and can drop-in replace the LM2903. But do note that it is a nanopower comparator and is much slower (55us) than the LM2903 (1us).
There was a PCN describing the changes in the part markings – this is company wide.
https://www.mouser.com/PCN/Texas_Instruments_PCN20211123004_2022022410013610.pdf
Main changes are removal of the pin 1 bar, removal of the TI logo, removal of the “Gx” marking, adding the pin one dot and a change to a OCR friendly font. This is expected.
