DM74LS47 - Fairchild Semiconductor

DM74LS47

BCD to 7-Segment Decoder/Driver with Open-Collector

Outputs

General Description

The ’LS47 accepts four lines of BCD (8421) input data, gen-

erates their complements internally and decodes the data

with seven AND/OR gates having open-collector outputs to

drive indicator segments directly. Each segment output is

guaranteed to sink 24 mA in the ON (LOW) state and with-

stand 15V in the OFF (HIGH) state with a maximum leakage

current of 250 µA. Auxiliary inputs provided blanking, lamp

test and cascadable zero-suppression functions.

Features

nOpen-collector outputs

nDrive indicator segments directly

nCascadable zero-suppression capability

nLamp test input

Connection Diagram

Pin Names Description

A0–A3 BCD Inputs

RBI Ripple Blanking Input (Active LOW)

LT Lamp Test Input (Active LOW)

BI/RBO Blanking Input (Active LOW) or

Ripple Blanking Output (Active LOW)

a–g *

Segment Outputs (Active LOW)

Note 1: *OC—Open Collector

Dual-In-Line Package

DS009817-1

Order Number DM54LS47J, DM54LS47W,

DM74LS47M or DM74LS47N

See Package Number J16A, M16A, N16E or W16A

March 1998

DM74LS47 BCD to 7-Segment Decoder/Driver with Open-Collector Outputs

Absolute Maximum Ratings (Note 2)

Supply Voltage 7V

Input Voltage 7V

Operating Free Air Temperature Range

DM54LS −55˚C to +125˚C

DM74LS 0˚C to +70˚C

Storage Temperature Range −65˚C to +150˚C

Recommended Operating Conditions

Symbol Parameter DM54LS47 DM74LS47 Units

Min Nom Max Min Nom Max

Supply Voltage 4.5 5 5.5 4.75 5 5.25 V

High Level Input Voltage 2 2 V

Low Level Input Voltage 0.7 0.8 V

High Level Output Currenta−g −50 −250 µA

@15V =V

(Note 3)

High Level Output Current BI /RBO −50 µA

Low Level Output Current 12 24 mA

Free Air Operating Temperature −55 125 0 70 ˚C

Note 2:

The “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these

limits. The parametric values defined in the “Electrical Characteristics” table are not guaranteed at the absolute maximum ratings. The “Recommended Operating

Conditions” table will define the conditions for actual device operation.

Note 3: OFF state at a–g.

Electrical Characteristics

Over recommended operating free air temperature range (unless otherwise noted)

Symbol Parameter Conditions Min Typ Max Units

(Note 4)

Input Clamp Voltage V

=Min, I

=−18 mA −1.5 V

High Level V

=Min, I

=Max, DM54 2.4 V

Output Voltage V

=Max, BI /RBO DM74 2.7 3.4

OFF

Output High Current V

=5.5V, V

=15Va−g 250 µA

Segment Outputs

Low Level V

=Min, I

=Max, DM54 0.4

Output Voltage V

=Min,a−g DM74 0.35 0.5

=3.2 mA, BI /RBO DM74 0.5 V

=12 mA, a –g DM74 0.25 0.4

=1.6 mA, BI /RBO DM74 0.4

Input Current @Max V

=Max, V

=7V DM74 100 µA

Input Voltage V

=Max, V

=10V DM54

High Level Input Current V

=Max, V

=2.7V 20 µA

Low Level Input Current V

=Max, V

=0.4V −0.4 mA

Short Circuit V

=Max DM54 −0.3 −2.0 mA

Output Current (Note 5) , I

at BI/RBO DM74 −0.3 −2.0

Supply Current V

=Max 13 mA

Note 4: All typicals are at VCC =5V, TA=25˚C.

Note 5: Not more than one output should be shorted at a time, and the duration should not exceed one second.

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Switching Characteristics

at V

=+5.0V, T

=+25˚C

=665Ω

Symbol Parameter Conditions C

=15 pF Units

Min Max

PLH

Propagation Delay 100 ns

PHL

An to a –g 100

PLH

Propagation Delay 100 ns

PHL

RBI to a –g (Note 6) 100

Note 6: LT =HIGH, A0–A3 =LOW

Functional Description

The ’LS47 decodes the input data in the pattern indicated in

the Truth Table and the segment identification illustration. If

the input data is decimal zero, a LOW signal applied to the

RBI blanks the display and causes a multidigit display. For

example, by grounding the RBI of the highest order decoder

and connecting its BI/RBO to RBI of the next lowest order

decoder, etc., leading zeros will be suppressed. Similarly, by

grounding RBI of the lowest order decoder and connecting

its BI/RBO to RBI of the next highest order decoder, etc.,

trailing zeros will be suppressed. Leading and trailing zeros

can be suppressed simultaneously by using external gates,

i.e.: by driving RBI of a intermediate decoder from an OR

gate whose inputs are BI/RBO of the next highest and lowest

order decoders. BI/RBO also serves as an unconditional

blanking input. The internal NAND gate that generates the

RBO signal has a resistive pull-up, as opposed to a totem

pole, and thus BI/RBO can be forced LOW by external

means, using wired-collector logic. A LOW signal thus ap-

plied to BI/RBO turns off all segment outputs. This blanking

feature can be used to control display intensity by varying

the duty cycle of the blanking signal.ALOW signal applied to

LT turns on all segment outputs, provided that BI/RBO is not

forced LOW.

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Logic Diagram

Numerical Designations—Resultant Displays

DS009817-3

DS009817-4

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Logic Symbol

Truth Table

Decimal Inputs Outputs

or Note

Function LT RBI A3 A2 A1 A0 BI/RBO a b c d e f g

0 HHLLLL H LLLLLLH (Note 7)

1 H X L L L H H HLLHHHH (Note 7)

2 H X L L H L H LLHLLHL

3 H X L L H H H LLLLHHL

4 H X L H L L H HLLHHLL

5 H X L H L H H LHLLHLL

6 H X L H H L H HHLLLLL

7 H X L H H H H LLLHHHH

8 H X H L L L H LLLLLLL

9 H X H L L H H LLLHHLL

10 HXHLHL H HHHLLHL

11 H X H L H H H HHLLHHL

12 H X H H L L H HLHHHLL

13 H X H H L H H LHHLHLL

14 H X H H H L H HHHLLLL

15 H X HHHH H HHHHHHH

BI X X XXXX L HHHHHHH (Note 8)

RBI HL LLLL L HHHHHHH (Note 9)

LT L X XXXX H LLLLLLL (Note 10)

Note 7: BI/RBO is wire-AND logic serving as blanking input (BI ) and/or ripple-blanking output (RBO ). The blanking out (BI ) must be open or held at a HIGH level

when output functions 0 through 15 are desired, and ripple-blanking input (RBI ) must be open or at a HIGH level if blanking or a decimal 0 is not desired. X =input

may be HIGH or LOW.

Note 8: When a LOW level is applied to the blanking input (forced condition) all segment outputs go to a HIGH level regardless of the state of any other input con-

dition.

Note 9: When ripple-blanking input (RBI) and inputsA0, A1,A2 and A3 are LOW level, with the lamp test input at HIGH level, all segment outputs go to a HIGH level

and the ripple-blanking output (RBO ) goes to a LOW level (response condition).

Note 10: When the blanking input/ripple-blanking output (BI/RBO ) is open or held at a HIGH level, and a LOW level is applied to lamp test input, all segment outputs

go to a LOW level.

DS009817-2

VCC =Pin 16

GND =Pin 8

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Physical Dimensions inches (millimeters) unless otherwise noted

16-Lead Ceramic Dual-In-Line Package (J)

Order Number DM54LS47J

Package Number J16A

16-Lead Small Outline Molded Package (M)

Order Number DM74LS47M

Package Number M16A

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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

16-Lead Molded Dual-In-Line Package (N)

Order Number DM74LS47N

Package Number N16E

16-Lead Ceramic Flat Package (W)

Order Number DM54LS47W

Package Number W16A

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LIFE SUPPORT POLICY

FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DE-

VICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMI-

CONDUCTOR CORPORATION. As used herein:

1. Life support devices or systems are devices or sys-

tems which, (a) are intended for surgical implant into

the body, or (b) support or sustain life, and (c) whose

failure to perform when properly used in accordance

with instructions for use provided in the labeling, can

be reasonably expected to result in a significant injury

to the user.

2. A critical component in any component of a life support

device or system whose failure to perform can be rea-

sonably expected to cause the failure of the life support

device or system, or to affect its safety or effectiveness.

Fairchild Semiconductor

Corporation

Americas

Customer Response Center

Tel: 1-888-522-5372

www.fairchildsemi.com

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Email: europe.support@nsc.com

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Tel: +852 2737-7200

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Tel: 81-3-5620-6175

Fax: 81-3-5620-6179

DM74LS47 BCD to 7-Segment Decoder/Driver with Open-Collector Outputs

Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and Fairchild reserves the right at any time without notice to change said circuitry and specifications.