Logic Families
117
+V
+V
A
B
Y = A.B
B
A
Y = A+B
+V
A
B
Y = A.B
(a)
(b)
(c)
Figure 5.1 (a) Diode logic (b) resistor transistor logic and (c) diode transistor logic.
5.1.2.2 CMOS Subfamilies
The popular CMOS subfamilies include the 4000A, 4000B, 4000UB, 54/74C, 54/74HC, 54/74HCT,
54/74AC and 54/74ACT families. The 4000A CMOS family has been replaced by its high-voltage
versions in the 4000B and 4000UB CMOS families, with the former having buffered and the latter
having unbuffered outputs. 54/74C, 54/74HC, 54/74HCT, 54/74AC and 54/74ACT are CMOS logic
families with pin-compatible 54/74 TTL series logic functions.