74LS169 Synchronous 4-Bit Up Down Binary Counter IC 74 LS 169 Counter IC SN74LS169-PDIP-16a

Product Overview

These are synchronous presettable counters that feature internal carry look-ahead circuitry, making them ideal for cascading in high-speed counting applications. The 'LS169B and 'S169 are 4-bit binary counters that operate fully synchronously, meaning all flip-flops are clocked simultaneously, helping to eliminate the output counting spikes typically found in asynchronous (ripple-clock) counters.

Core Specifications

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  Operating Voltage: Specified at a nominal 5V.

• Counting Frequency:

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    'LS169B: Typical maximum frequency of 35 MHz (both up and down counting).

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    'S169: Typical maximum frequency of 55 MHz (down) and 70 MHz (up).

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  Power Dissipation: * 'LS169B: Typical 100 mW.

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    'S169: Typical 500 mW.

Features

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  Fully Synchronous Operation: All flip-flops change output coincidentally when instructed by count-enable inputs and internal gating.

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  Programmable: The counters are fully programmable; outputs can be preset to either level.

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  Cascading: Carry look-ahead circuitry and a carry output allow for cascading counters for n-bit synchronous applications without the need for additional gating.

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  Clocking: Features a fully independent clock circuit with a buffered clock input that triggers master-slave flip-flops on the rising edge.

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  Control Inputs: Two count-enable inputs (ENP and ENT) must be low to count. The direction (up or down) is determined by the up/down input level.

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  Load Input: Loading is synchronous; setting the load input low disables the counter and causes outputs to align with data inputs after the next clock pulse.

Applications

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  High-Speed Counting: Suitable for systems requiring fast, synchronous counting where output spikes must be avoided.

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  Cascaded Counting: Used for n-bit applications through the use of the carry output pulse, which can enable successive cascaded stages.

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  Programmable Counters: Ideal for designs where outputs need to be preset or where counting modes (enabled, disabled, loading, counting) must be dictated by specific conditions.