Dictionary of Electronic Terms
"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.
A 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]. Also refer to a Counter in VHDL.
4-bit Counters by Function:
Note in most cases when a 74xx device is listed, but a 54xx device may also available.
74xx represents the commercial temperature range and 54xx represents the industrial [military] temperature range [IC Prefixes].
74190 Synchronous Up/Down BCD Counter
74191 Synchronous Up/Down 4-Bit Binary Counter
74192 Up / Down Decade Counter
74193 Presettable Synchronous 4-Bit Binary Up/Down Counters
Standard TTL part numbers are shown but it's more likely that a newer logic family would still be in production; 54AC190, 54ACT191, 54HC192 and so on.
Part number Decode [SN54AC192x]
SN; designated Texas Instruments [Company prefix Prefixes]
54; military temperature range [IC temp Ranges]
AC; Advanced CMOS [Logic Families]
192; logic function [4-bit Decade Counter]
x; package style [Types of IC Packages]
MIL-M-38510/344: Advanced Schottky TTL, Decade Counters
54F160, 54F162, 54F190, 54F192
Note the 'F' or Fast series is the same TTL family as the 'AS' or Advanced Schottky series.
Editor note; Many TTL logic ICs have alternate pin outs so keep that in mind when reviewing parts or functional pinouts. In almost all cases any time you see a package pin out, that pinout is for the common part and not the alternate part, but you never know. While writing this, I don't recall if this component has an alternate pin out, but it's something to think about.
