74Ls48

DM74LS48 BCD to 7-Segment Decoder

January 1992

DM74LS48 BCD to 7-Segment Decoder
General Description
The ’LS48 translates four lines of BCD (8421) input data into the 7-segment numeral code and provides seven corresponding outputs having pull-up resistors as opposed to totem pole pull-ups These outputs can serve as logic signals with a HIGH output corresponding to a lighted lamp segmentor can provide a 1 3 mA base current to npn lamp driver transistors Auxiliary inputs provide lamp test blanking and cascadable zero-suppression functions The ’LS48 decodes the input data in the pattern indicated in the Truth Table and the segment identification illustration

Connection Diagram
Dual-In-Line Package

TL F 10172 – 1

Order Number DM74LS48M or DM74LS48N See NS Package NumberM16A or N16E

C1995 National Semiconductor Corporation

TL F 10172

RRD-B30M105 Printed in U S A

Absolute Maximum Ratings (Note)
Supply Voltage Input Voltage Operating Free Air Temperature Range DM74LS Storage Temperature Range 7V 7V 0 C to a 70 C
b 65 C to a 150 C

Note The ‘‘Absolute Maximum Ratings’’ are those values beyond which the safety of the device cannot be guaranteed Thedevice 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

Recommended Operating Conditions
Symbol VCC VIH VIL IOH IOL TA Parameter Min Supply Voltage High Level Input Voltage Low LevelInput Voltage High Level Output Current Low Level Output Current Free Air Operating Temperature 0 4 75 2 08
b 50

DM74LS48 Nom 5 Max 5 25

Units V V V mA mA C

60 70

Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted)
Symbol VI VOH IOFF VOL Parameter Input Clamp Voltage High Level Output Voltage Output High Current Segment OutputsLow Level Output Voltage Conditions VCC e Min II e b18 mA VCC Min IOH e Max VIL e Max VCC e Min VO e 0 85V VCC e Min IOL e Max VIH e Min IOL e 2 0 mA VCC e Min II IIH IIL IOS ICCH Input Current Input Voltage Max VCC e Max VI e 7V VCC e Max VI e 2 7V VCC e Max VI e 0 4V VCC e Max VO e 0V at BI RBO (Note 2) VCC e Max VIN e 4 5V
b0 3

Min

Typ (Note 1)

Max
b1 5

Units V V mA

24
b1 305 04 01 20
b0 4 b2

V

mA mA mA mA mA

High Level Input Current Low Level Input Current Short Circuit Output Current Supply Current

38

Note 1 All typicals are at VCC e 5V TA e 25 C Note 2 Not more than one output should be shorted at a time and the duration should not exceed one second

Switching Characteristics at VCC e 5V and TA e 25 C
Symbol tPLH tPHL tPLH tPHL
Note LT e HIGHA0 –A3 e HIGH

Parameter Min Propagation Delay Time An to a–g Propagation Delay Time RBI to a–f

CL e 15 pF Max 100 100 100 100

Units

ns ns

2

Numerical Designations Resultant Displays

TL F 10172 – 4

Truth Table
Decimal Or Function 0 (Note 1) 1 (Note 1) 2 3 4 5 6 7 8 9 10 11 12 13 14 15 BI (Note 2) RBI (Note 3) LT (Note 4) Inputs LT H H H H H H H H H H H H H H H H X H L RBI HX X X X X X X X X X X X X X X X L X A3 L L L L L L L L H H H H H H H H X L X A2 L L L L H H H H L L L L H H H H X L X A1 L L H H L L H H L L H H L L H H X L X A0 L H L H L H L H L H L H L H L H X L X BI RBO H H H H H H H H H H H H H H H H L L H a H L H H L H L H H H L L L H L L L L H b H H H H H L L H H H L L H L L L L L H c H H L H H H H H H H L H L L L L L L H Outputs d H L H H L H H L H L H HL H H L L L H e H L H L L L H L H L H L L L H L L L H f H L L L H H H L H H L L H H H L L L H g L L H H H H H L H H H H H H H L L L H

Note 1 BI RBO is wired-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...