74ACT11191 SYNCHRONOUS 4-BIT UP/DOWN BINARY COUNTER

SCAS106A - D3455, FEBRUARY 1990 - REVISED APRIL 1993

features

• Inputs Are TTL-Voltage Compatible
• Single Down/Up Count Control Line
• Look-Ahead Circuitry Enhances Speed of Cascaded Counters
• Fully Synchronous in Count Modes
• Asynchronously Presettable With Load Control
• Flow-Through Architecture Optimizes PCB Layout
• Center-Pin V_CC and GND Configurations to Minimize High-Speed Switching Noise
• EPIC^TM (Enhanced-Performance Implanted CMOS) 1-m Process
• Package Options Include Plastic Small-Outline Packages and Standard Plastic 300-mil DIPs

  EPIC is a trademark of Texas Instruments Incorporated.

description

The 74ACT11191 is a synchronous, 4-bit binary reversible up/downcounter. A synchronous counting operation is provided by having allflip-flops clocked simultaneously so that the outputs changecoincident with each other when so instructed by the steering logic.This mode of operation eliminates the output counting spikes normallyassociated with asynchronous (ripple clock) counters.

The outputs of the four flip-flops are triggered on alow-to-high-level transition of the clock input if the enable input() is low. Ahigh at inhibitscounting. The direction of the count is determined by the level ofthe down/up (D/U\) input. When D/U\ is low, the counter counts up andwhen D/U\ is high, it counts down.

These counters feature a fully independent clock circuit. Changesat the control inputs ( andD/U\) that will modify the operating mode have no effect on thecontents of the counter until clocking occurs. The function of thecounter will be dictated solely by the condition meeting the stablesetup and hold times.

View more information about generic part numbers:74ACT11191

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(c) Copyright 1998 Texas Instruments Incorporated. All rights reserved.
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