Does TTL output specify the maximum current it can source? TTL-compatible inputs and outputs can be made with CMOS structures If you look at the datasheets for a 74HC04 and 74HCT04, you will see the different input voltage ranges AND - to your specific question - No These days, when a component or device specifies a TTL output, it is referring to the voltage levels only
How does TTL serial work? - Electrical Engineering Stack Exchange Point of terminology: "TTL serial" is a severely over-broad term, " (point-to-point) asynchronous serial (at TTL levels)" seems to be what you're asking about (Though that's still probably lacking, but at least better)
transistors - Experiment for driving LED with TTL output - Electrical . . . In TTL, 5V is a supply voltage, not an output logic level The "0 5V levels" are an idealization Real TTL systems do not work with 0 5V levels They sure accept 5V inputs, but anything above 2V on an input is a high level! TTL outputs with even a single TTL or TTL-LS load on them have 5V only on the supply lines
Is it possible to drive TTL inputs from 3. 3 V microcontroller? The problem with the term "TTL" is it's often used rather loosely People often say "TTL" when they really mean 5V CMOS Real 5V TTL (74LS and similar) has 3 3V compatible input thresholds but has much higher input current requirements than any CMOS device does So you need to make sure your 3 3V device can deliver enough current for the TTL inputs This is probablly not a problem for driving