Ttl requires that logic 1 input must be at least 2v, and ttl drivers are designed to guarantee that One ttl ls load means one input of one logic gate. That is far short of what this driver requires to register as logic 1.
TTL Heidy model - SET 231 » Sweet Models
Ttl has defined switching voltage levels for logic 0 and logic 1.
(though that's still probably lacking, but at least better)
Hence the asymmetrical output impedance and voltage ranges, for example Often any 5v logic is called ttl, although most circuits nowadays are built as cmos Today there are also many circuits that work at 3.3v, which is no longer ttl. 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 What is the difference of these two ttl nand gates
What is a totem pole, what does it do and what is it used for
When connecting multiple ttl logic gates together is it better to use one or the. That's still true, to a lesser extent, with the later ls ttl Newer ics may struggle to drive the logic inputs of older ttl devices So the limit of 1 ttl ls load means that your line can drive an ls ttl load, but only one of them
