| Electronics > Projects, Designs, and Technical Stuff |
| 74HCT74 NXP vs Texas |
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| Zero999:
What are you trying to achieve the the resistors and capacitor. |
| Bassman59:
--- Quote from: Jan Audio on December 25, 2018, 05:38:47 pm ---Thanks, i will re-check my circuit again, hope the Texas works since i have 100 piece. --- End quote --- Post a schematic. |
| David Hess:
For the same part from different manufacturers, some clock inputs are implemented as schmitt triggers and some are not but this is not always reflected accurately in the datasheets. This may be one of the later cases and it is exactly what I would expect of the 74HCT74. The only way to be sure is to either qualify the parts or include your own schmitt trigger before the clock input if you are going to use different manufacturers. |
| Jan Audio:
Here was the NXP schematic : 2N2 [ 12v waveform ]-----[8K2]-----||------+----[10K]---ground; +----|<4148]---ground; +----[CLK] I fixed it with this for Texas : 2N2 [ 12v waveform ]-----------------||------+----[1K]---ground; +----|<4148]---ground; +----[CLK] Maybe it is a bit short circuit like this ? --- Quote from: wraper on December 25, 2018, 05:39:42 pm ---You shall not input signals with slow rise/fall time into CMOS ICs to begin with. The only exception are ICs with schmitt trigger inputs. --- End quote --- Ok, thank you i did not know. |
| wraper:
--- Quote from: Jan Audio on December 26, 2018, 01:26:04 pm ---[ 12v waveform ]-----[8K2]-----||------+----[10K]---ground; +----|<4148]---ground; +----[CLK] I fixed it with this for Texas : 2N2 [ 12v waveform ]-----------------||------+----[1K]---ground; +----|<4148]---ground; +----[CLK] --- End quote --- Some piece of nonsense you made there. If you need to reduce voltage from 12V, why not use resistive divider of resistor + zener diode? And why don't you draw normal circuit? |
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