
Product Folder: SN74HC193, 4-Bit Synchronous Up/Down Counters (Dual Clock With Clear)
SN74HC193, 4-Bit Synchronous Up/Down Counters (Dual Clock With Clear)
DEVICE STATUS: ACTIVE
Voltage Nodes (V) 6, 5, 2
6, 5, 2
Vcc range (V)
2.0 to 6.0
Input Level
CMOS
Output Level
CMOS
Output Drive (mA)
-4/4
Output
2S
Clear
Async
FEATURES
q
Look-Ahead Circuitry Enhances Cascaded Counters
q
Fully Synchronous in Count Modes
q
Parallel Asynchronous Load for Modulo-N Count Lengths
q
Asynchronous Clear
q
Package Options Include Plastic Small-Outline (D) and Ceramic Flat (W) Packages, Ceramic Chip Carriers (FK), and Standard Plastic (N) and Ceramic (J) 300-mil DIPs
DESCRIPTION
The 'HC193 are 4-bit synchronous, reversible, up/down binary counters. Synchronous operation is provided by having all flip-flops clocked simultaneously so that the outputs change coincidentally
with each other when so instructed by the steering logic. This mode of operation eliminates the output counting spikes normally associated with asynchronous (ripple-clock) counters.
The outputs of the four flip-flops are triggered on a low-to-high-level transition of either count (clock) input (UP or DOWN). The direction of counting is determined by which count input is pulsed
while the other count input is high.
All four counters are fully programmable; that is, each output may be preset to either level by placing a low on the load (LOAD\) input and entering the desired data at the data inputs. The output
changes to agree with the data inputs independently of the count pulses. This feature allows the counters to be used as modulo-N dividers by simply modifying the count length with the preset
inputs.
A clear (CLR) input has been provided that forces all outputs to the low level when a high level is applied. The clear function is independent of the count and LOAD\ inputs.
These counters were designed to be cascaded without the need for external circuitry. The borrow (BO\) output produces a low-level pulse while the count is zero (all outputs low) and DOWN is low.
Similarly, the carry (CO\) output produces a low-level pulse while the count is maximum (9 or 15) and UP is low. The counters can then be easily cascaded by feeding BO\ and CO\ to DOWN and
UP, respectively, of the succeeding counter.
The SN54HC193 is characterized for operation over the full military temperature range of -55°C to 125°C. The SN74HC193 is characterized for operation from -40°C to 85°C.
TECHNICAL DOCUMENTS
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