1 Features

? Count Divider Chain

? Digitally Programmable from 22 to 2n

(n = 31 for SN74LS292 , n = 15 for SN74LS294)

? Useable Frequency Range from DC to 30 MHz

? Easily Expandable

2 Applications

? Frequency Division

? Digital Timing

3 Description

The SN74LS29x devices are programmable

frequency dividers and digital timers contain 31 flipflops

plus 30 gates (in SN74LS292) or 15 flip-flops

plus 29 gates (in SN74LS294) on a single chip. The

count modulo is under digital control of the inputs

provided.

Both types feature an active-low CLR clear input to

initialize the state of all flip-flops. To facilitate the

incoming inspection, test points are provided (TP1,

TP2, and TP3 on the SN74LS292, and TP on the

SN74LS294). These test points are not intended to

drive system loads. Both types feature two clock

inputs; either one may be used for clock gating (see

Table 1).

A brief look at the digital timing capabilities of the

SN74LS292 shows that with a 1-MHz input

frequency, programming for 210 gives a period of

1.024 ms, 220 gives a period of 1.05 sec, 226 gives a

period of 1.12 min, and 231 gives a period of 35.79

min.

These devices are easily cascadable, giving limitless

possibilities to achievable timing delays.