FIGURE 14. Method of connecting the 4503B for use
as six normal buffers.
FIGURE 15. Method of connecting the 4503B for use as a three-state
Hex buffer controlled via a single input.
FIGURE 16. Functional diagram of the 7407 Hex
buffer with 30V o.c. outputs.
FIGURE 17. A 5V to high-voltage buffer/interface.
FIGURE 18. Three 7407 buffers used
to make a three-input wired AND gate.
its normal mode via its control input.
Dealing now with the individual
buffer ICs listed in Figure 7, Figure 8
shows the functional diagram and
truth table, etc., of the 74LS125 TTL
IC, which houses four independently
controlled, three-state buffers and is
so modestly priced that it is still worth
using, even if you do not need the
three-state facility. Note from the truth
table that each of the four elements
acts as a normal buffer when its control terminal (C) is in the logic 0 state,
and that the element’s quiescent
current (Is) is least when C is at logic 0
FIGURE 19. Functional diagram
and truth table of the 74LS365
Hex three-state buffer.
and the buffer’s input (A) is at logic 1.
Thus, any unwanted elements
should be disabled by tying their C
terminals low and their A terminals
high, using one of the methods shown
in Figure 9. Any element can be used
FIGURE 21. Methods of connecting the
74LS365 for use as a three-state Hex
buffer controlled via a single input.
FIGURE 20. Methods of connecting the
74LS365 for use as six normal buffers.
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