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Standard Products

UT54ACS190/UT54ACTS190

Synchronous 4-Bit Up-Down BCD Counters

Datasheet

November 2010

www.aeroflex.com/logic

FEATURES

Single down/up count control line

Look-ahead circuitry enhances speed of cascaded counters

Fully synchronous in count modes

Asynchronously presettable with load control

1.2μ CMOS

- Latchup immune

High speed

Low power consumption

Single 5 volt supply

Available QML Q or V processes

Flexible package

- 16-pin DIP

- 16-lead flatpack

UT54ACS190 - SMD 5962-96562

UT54ACTS190 - SMD 5962-96563

DESCRIPTION

The UT54ACS190 and the UT54ACTS190 are synchronous 4-

bit reversible up-down BCD decade counters. Synchronous

counting operation is provided by having all flip-flops clocked

simultaneously so that the outputs change coincident with each

other when so instructed. Synchronous operation eliminates the

output counting spikes associated with asynchronous counters.

The outputs of the four flip-flops are triggered on a low-to-high-

level transition of the clock input if the enable input (CTEN) is

low. A logic one applied to CTEN inhibits counting. The di-

rection of the count is determined by the level of the down/up

(D/U) input. When D/U is low, the counter counts up and when

D/U is high, it counts down.

The counters feature a fully independent clock circuit. Changes

at control inputs (CTEN and D/U) that will modify the operating

mode have no effect on the contents of the counter until clocking

occurs.

The counters are fully programmable. The outputs may be preset

to either logic level by placing a low on the load input and en-

tering the desired data at the data inputs. The output will change

to agree with the data inputs independently of the level of the

clock input. The asynchronous load allows counters to be used

as modulo-N dividers by simply modifying the count length with

the preset inputs.

If preset to an illegal state, the counter returns to a normal se-

quence in one or two counts.

PINOUTS

16-Pin DIP

Top View

16-Lead Flatpack

Top View

Two outputs have been made available to perform the cascading

function: ripple clock and maximum/minimum (MAX/MIN)

count. The MAX/MIN output produces a high-level output

pulse with a duration approximately equal to one complete cycle

of the clock while the count is zero (all outputs low) counting

down or maximum (9) counting up.

The ripple clock output (RCO) produces a low-level output pulse

under those same conditions but only while the clock input is

low. The counters easily cascade by feeding the RCO to the

enable input of the succeeding counter if parallel clocking is

used, or to the clock input if parallel enabling is used. Use the

MAX/MIN count output to accomplish look-ahead for high-

speed operation.

The devices are characterized over full military temperature

range of -55

°C to +125°C.

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2

3

4

5

7

6

16

15

14

13

12

10

11

B

CTEN

D/U

A

CLK

RCO

MAX/MIN

C

8

9

D

LOAD

1

2

3

4

5

7

6

16

15

14

13

12

10

11

89

B

CTEN

D/U

A

CLK

RCO

MAX/MIN

LOAD

C

D