74LS48

SN54LS48 MOTOROLA | Alldatasheet

Document overview

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Technical content

The SN54 /74LS48 is a BCD to 7-Segment Decoder consisting of NAND gates, input buffers and seven AND-OR-INVER T gates. Seven NAND gates and one driver are connected in pairs to make BCD data and its complement available to the seven decoding AND-OR-INVERT gates. The remaining NAND gate and three input buffers provide lamp test, blanking input/ripple- blanking input for the LS48. The circuit accepts 4-bit binary-coded-decimal (BCD) and, depending on the state of the auxiliary inputs, decodes this data to drive other components. The relative positive logic output levels, as well as conditions required at the auxiliary inputs, are shown in the truth tables. The LS48 circuit incorporates automatic leading and/or trailing edge zero-blanking control (RBI and RBO). Lamp Test (LT) may be activated any time when the BI/RBO node is HIGH. Both devices contain an overriding blanking input (BI) which can be used to control the lamp intensity by varying the frequency and duty cycle of the BI input signal or to inhibit the outputs.

• Lamp Intensity Modulation Capability (BI/RBO)
• Internal Pull-Ups Eliminate Need for External Resistors
• Input Clamp Diodes Eliminate High-Speed T ermination Effects 14 13 12 11 10 9 1 2 3 4 5 6 VCC 16 15 f g a b c d e B C LT BI / RBORBI D A GND CONNECTION DIAGRAM DIP (TOP VIEW) LOGIC DIAGRAM INPUT BLANKING INPUT OR RIPPLE-BLANKING OUTPUT RIPPLE-BLANKING INPUT LAMP-TEST INPUT A B C D a b c d e f g OUTPUT SN54/74LS48 BCD TO 7-SEGMENT DECODER LOW POWER SCHOTTKY J SUFFIX CERAMIC CASE 620-09 N SUFFIX PLASTIC CASE 648-08

ORDERING INFORMATION

VCC = PIN 16 GND = PIN 8 7 1 2 6 3 5 13 12 11 10 9 15 14 4 A B C D LT RBI a b c d e f g BI/ RBO SN54/74LS48

NUMERICAL DESIGNATIONS — RESULTANT DISPLAYS 0 1 2 3 4 5 6 7 8 9 10 11 12 13 NOTES: (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 HIGH level if blanking of a decimal 0 is not desired. X=input may be HIGH or LOW. (2) When a LOW level is applied to the blanking input (forced condition) all segment outputs go to a LOW level, regardless of the state of any other input condition. (3) When ripple-blanking input (RBI) and inputs A, B, C, and D are at 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). (4) 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. TRUTH TABLE SN54/74LS48 INPUTS OUTPUTS 5-60 FAST AND LS TTL DATA SN54/74LS48 PIN NAMES LOADING (Note a) HIGH LOW A, B, C, D RBI LT BI/RBO BI BCD Inputs Ripple-Blanking (Active Low) Input Lamp-Test (Active Low) Input Blanking Input or Ripple- Blanking Output (Active Low) Blanking (Active Low) Input 0.5 U.L. 0.5 U.L. 0.5 U.L. 0.5 U.L. 1.2 U.L. 0.5 U.L. Open-Collector 0.25 U.L. 0.25 U.L. 0.25 U.L. 0.75 U.L. 2(1) U.L. 0.25 U.L. NOTES: a) Unit Load (U.L.) = 40 µA HIGH / 1.6 mA LOW b)Outut current measured at VOUT = 0.5 V DECIMAL OR FUNCTION LT RBI D C B A BI / RBO a b c d e f g NOTE

0 H H L L L L H H H H H H H L 1

1 H X L L L H H L H H L L L L 1

2 H X L L H L H H H L H H L H

3 H X L L H H H H H H H L L H

4 H X L H L L H L H H L L H H

5 H X L H L H H H L H H L H H

6 H X L H H L H L L H H H H H

7 H X L H H H H H H H L L L L

8 H X H L L L H H H H H H H H

9 H X H L L H H H H H L L H H

10 H X H L H L H L L L H H L H

11 H X H L H H H L L H H L L H

12 H X H H L L H L H L L L H H

13 H X H H L H H H L L H L H H

14 H X H H H L H L L L H H H H

15 H X H H H H H L L L L L L L

BI X X X X X X L L L L L L L L 2 RBI H L L L L L L L L L L L L L 3 LT L X X X X X H H H H H H H H 4

GUARANTEED OPERATING RANGES Symbol Parameter Min Typ Max Unit VCC Supply Voltage 54 4.5 4.75 5.0 5.0 5.5 5.25 V TA Operating Ambient T emperature Range 54 –55 125 IOH Output Current — High a to g 54, 74 –100 µA IOH Output Current — High BI/RBO 54, 74 –50 µA IOL Output Current — Low a to g 54 2.0 6.0 mA IOL Output Current — Low BI/RBO BI/RBO 1.6 3.2 mA DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified) Symbol Parameter Limits Unit Test ConditionsSymbol Parameter Min Typ Max Unit Test Conditions VIH Input HIGH Voltage 2.0 V Guaranteed Input HIGH Voltage for All Inputs VIL Input LOW Voltage 54 0.7 V Guaranteed Input LOW Voltage for All InputsVIL Input LOW Voltage 74 0.8 V Guaranteed Input LOW Voltage for All Inputs VIK Input Clamp Diode Voltage –1.5 V VCC = MIN, IIN = –18 mA VOH Output HIGH Voltage 2.4 4.2 µA VCC = MIN, IOH = –50 µA, VIN = VIH or U.L. per Truth TableVOH Output HIGH Voltage 2.4 4.2 µA VCC = MIN, IOH = –50 µA, VIN = VIH or U.L. per Truth Table IO Output Current a to g –1.3 –2.0 mA VCC = MIN, VO = 0.85 V Input Conditioner as for VOH VOL Output LOW Voltage a to g 54, 74 0.4 V IOL = 2.0 mA VCC = MIN, VIH = 2.0 V VIL = VIL MAXVOL Output LOW Voltage a to g 74 0.5 V IOL = 6.0 mA VCC = MIN, VIH = 2.0 V VIL = VIL MAX VOL Output LOW Voltage BI/RBO 54, 74 0.4 V IOL = 1.6 mA VCC = MAX, VIH = 2.0 V VIL = VIL MAXVOL Output LOW Voltage BI/RBO 74 0.5 V IOL = 3.2 mA VCC = MAX, VIH = 2.0 V VIL = VIL MAX IIH Input HIGH Current (Except BI/RBO) 20 µA VCC = MAX, VIN = 2.7 V IIH Input HIGH Current (Except BI/RBO) 0.1 mA VCC = MAX, VIN = 7.0 V IIL Input LOW Current (Except BI/RBO) –0.4 mA VCC = MAX, VIN = 0.4 V IIL Input LOW Current BI/RBO –1.2 mA VCC = MAX, VIN = 0.4 V ICC Power Supply Current 25 38 mA VCC = MAX IOS Short Circuit Current BI/RBO (Note 1) –0.3 –2.0 mA VCC = MAX Note 1: Not more than one output should be shorted at a time, nor for more than 1 second. AC CHARACTERISTICS (VCC = 5.0 V, TA = 25°C) Symbol Parameter Limits Unit Test ConditionsSymbol Parameter Min Typ Max Unit Test Conditions tPHL Propagation Delay Time, HIGH-to-LOW Level Output from A Input 100 ns C L = 15 pF , RL = 4.0 kΩ tPLH Propagation Delay Time, LOW-to-HIGH Level Output from A Input 100 ns C L = 15 pF , RL = 4.0 kΩ tPHL Propagation Delay Time, HIGH-to-LOW Level Output from RBI Input 100 ns C L = 15 pF , RL = 6.0 kΩ tPLH Propagation Delay Time, LOW-to-HIGH Level Output from RBI Input 100 ns C L = 15 pF , RL = 6.0 kΩ