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AnalogKid
AnalogKid
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The output stage of an LS14, like almost all bipolar TTL circuits, does not swing all the way up to its Vcc (+5 V) because the pull-up device is an emitter follower. A simple change is to change the part to the CMOS 74ACT14. AC and ACT series gates have a much more robust output stage that can source and sink 24 mA with a relatively small voltage drop. When sourcing 4 mA it will swing much closer to its Vdd (+5 V).

The output stage of an LS14, like almost all bipolar TTL circuits, does not swing all the way up to its Vcc (+5 V) because the pull-up device is an emitter follower. A simple change is to change the part to the CMOS 74ACT14. AC series gates have a much more robust output stage that can source and sink 24 mA with a relatively small voltage drop. When sourcing 4 mA it will swing much closer to its Vdd (+5 V).

The output stage of an LS14, like almost all bipolar TTL circuits, does not swing all the way up to its Vcc (+5 V) because the pull-up device is an emitter follower. A simple change is to change the part to the CMOS 74ACT14. AC and ACT series gates have a much more robust output stage that can source and sink 24 mA with a relatively small voltage drop. When sourcing 4 mA it will swing much closer to its Vdd (+5 V).

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AnalogKid
AnalogKid
  • 23.2k
  • 1
  • 14
  • 40

The output stage of an LS14, like almost all bipolar TTL circuits, does not swing all the way up to its Vcc (+5 V) because the pull-up device is an emitter follower. A simple change is to change the part to the CMOS 74ACT14. AC series gates have a much more robust output stage that can source and sink 24 mA with a relatively small voltage drop. When sourcing 4 mA it will swing much closer to its Vdd (+5 V).