"A"
"B"
"C",
"D",
"E",
"F",
"G",
"H",
"I",
"J",
"K",
"L",
"M",
"N",
"O",
"P",
"Q",
"R",
"S",
"T",
"U",
"V",
"W",
"X",
"Y",
"Z"
IC Up/Down Counter Chips
4-Bit IC Up/Down Counter Circuit
IC Up/Down Counter. Presettable Synchronous 4-Bit Up/Down Counters.
Presetting the counter to the number on the preset data inputs (Input A - Input D) is accomplished by a LOW asynchronous parallel load input (Load). The counter is incremented on the low-to-high transition of the UP input (and a high level on the Clock- DOWN) and decremented on the low to high transition of the DOWN input (and a high level on the UP input). A high level on the CLR input overrides any other input to clear the counter to its zero state. The Terminal Count up (CO) goes low half a clock period before the zero count is reached and returns to a high level at the zero count.
The Terminal Count Down (BO) in the count down mode likewise goes low half a clock period before the maximum count (9 in the 192 and 15 in the 193) and returns to high at the maximum count. Cascading is effected by connecting the CO [carry] and BO [borrow] outputs of a less significant counter to the Clock-Up [UP] and Clock-Down [DOWN] inputs, respectively, of the next most significant counter.
An Counter would be considered standard logic or glue logic when a discrete IC is used. However, because of the internal complexity, an Identity Comparator would also be considered an MSI Function [Medium Scale Integration].
Counters by Function:
Note in most cases when a 74xx device is listed, a 54xx device is also available.
74xx represents the commercial temperature range and 54xx represents the industrial temperature range [IC Prefixes].
74190
74191
74192
74193 High Speed CMOS Logic Presettable Synchronous 4-Bit Binary Up/Down Counters
