| Electronics > Projects, Designs, and Technical Stuff |
| 74HCT74 NXP vs Texas |
| (1/9) > >> |
| Jan Audio:
Hi, merry cristmas. I have another problem : When i change my 74HCT74 from NXP to Texas instruments it dont works anymore. I have a square wave to 8K2 resistor going into a 2n2 capacitor, the capacitor out goes with a 10K and diode to ground and to the CLK input of the 74HCT74. Why is it different ? thanks btw : it does work somehow only it toggles twice really fast so the output looks like always on state. |
| rhb:
Perhaps you should post a schematic? That way readers would know what you're trying to do. |
| DaJMasta:
Is the TI part also an HCT series chip? Some different families require different voltages or have different response characteristics (or are open collector outputs, like the F series). Hard to tell exactly from your description, but is your clock input signal AC couple but not biased to stay above negative voltages (can cause erratic behavior)? Also could be that the TI part is configured to use any old edge trigger whereas the NXP part is only rising or falling edge - giving you 2x the switching rate - the datasheet should be able to tell you if that's the case, though usually these are different part numbers on the package (the 74 model should be positive edge triggered only). |
| Jan Audio:
Yes the Texas is the SN74HCT74N. |
| podericof:
Hi there, can you also tell us the complete PN for the 2 ICs? |
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