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Features

? Synchronous Programmable ÷N Counter N = 3 to 9999

or 15999

? Presettable Down-Counter

? Fully Static Operation

? Mode-Select Control of Initial Decade Counting

Function (÷10, 8, 5, 4, 2)

? Master Preset Initialization

? Latchable ÷N Output

? Fanout (Over Temperature Range)

- Standard Outputs . . . . . . . . . . . . . . . 10 LSTTL Loads

- Bus Driver Outputs . . . . . . . . . . . . . 15 LSTTL Loads

? Wide Operating Temperature Range . . . -55oC to 125oC

? Balanced Propagation Delay and Transition Times

? Significant Power Reduction Compared to LSTTL

Logic ICs

? HC Types

- 2V to 6V Operation

- High Noise Immunity: NIL = 30%, NIH = 30% of VCC

at VCC = 5V

Applications

? Communications Digital Frequency Synthesizers;

VHF, UHF, FM, AM, etc.

? Fixed or Programmable Frequency Division

? “Time Out” Timer for Consumer-Application Industrial

Controls

Description

The ’HC4059 are high-speed silicon-gate devices that are

pin-compatible with the CD4059A devices of the CD4000B

series. These devices are divide-by-N down-counters that

can be programmed to divide an input frequency by any

number “N” from 3 to 15,999. The output signal is a pulse

one clock cycle wide occurring at a rate equal to the input

frequency divide by N. The down-counter is preset by means

of 16 jam inputs.

The three Mode-Select Inputs Ka, Kb and Kc determine the

modulus (“divide-by” number) of the first and last counting

sections in accordance with the truth table. Every time the first

(fastest) counting section goes through one cycle, it reduces by

1 the number that has been preset (jammed) into the three

decades of the intermediate counting section an the last

counting section, which consists of flip-flops that are not

needed for opening the first counting section. For example, in

the ÷2 mode, only one flip-flop is needed in the first counting

section. Therefore the last counting section has three flip-flops

that can be preset to a maximum count of seven with a place

value of thousands. If ÷10 is desired for the first section, Ka is

set “high”, Kb “high” and Kc “l(fā)ow”. Jam inputs J1, J2, J3, and J4

are used to preset the first counting section and there is no last

counting section. The intermediate counting section consists of

three cascaded BCD decade (÷10) counters presettable by

means of Jam Inputs J5 through J16.

The Mode-Select Inputs permit frequency-synthesizer

channel separations of 10, 12.5, 20, 25 or 50 parts. These

inputs set the maximum value of N at 9999 (when the first

counting section divides by 5 or 10) or 15,999 (when the first

counting section divides by 8, 4, or 2).

The three decades of the intermediate counter can be preset

to a binary 15 instead of a binary 9, while their place values

are still 1, 10, and 100, multiplied by the number of the ÷N

mode. For example, in the ÷8 mode, the number from which

counting down begins can be preset to:

3rd Decade 1500

2nd Decade 150

1st Decade 15

Last Counting Section 1000

The total of these numbers (2665) times 8 equals 12,320.

The first counting section can be preset to 7. Therefore,

21,327 is the maximum possible count in the ÷8 mode.

The highest count of the various modes is shown in the

Extended Counter Range column. Control inputs Kb and Kc

can be used to initiate and lock the counter in the “master

preset” state. In this condition the flip-flops in the counter are

preset in accordance with the jam inputs and the counter

remains in that state as long as Kb and Kc both remain low. The

counter begins to count down from the preset state when a

counting mode other than the master preset mode is selected.

The counter should always be put in the master preset mode

before the ÷5 mode is selected. Whenever the master preset

mode is used, control signals Kb = “l(fā)ow” and Kc = “l(fā)ow” must

be applied for at least 3 full clock pulses.

After Preset Mode inputs have been changed to one of the ÷

modes, the next positive-going clock transition changes an

internal flip-flop so that the countdown can begin at the

second positive-going clock transition. Thus, after an MP

(Master Preset) mode, there is always one extra count

before the output goes high. Figure 1 illustrates a total count

of 3 (÷8 mode). If the Master Preset mode is started two

clock cycles or less before an output pulse, the output pulse

will appear at the time due. If the Master Preset Mode is not

used, the counter jumps back to the “Jam” count when the

output pulse appears.

A “high” on the Latch Enable input will cause the counter

output to remain high once an output pulse occurs, and to

remain in the high state until the latch input returns to “l(fā)ow”.

If the Latch Enable is “l(fā)ow”, the output pulse will remain high

for only one cycle of the clock-input signal.