SN54/74LS48 BCD TO 7-SEGMENT DECODER The SN54 / 74LS48 is a BCD to 7-Segment Decoder consisting of NAND gates, input buffers and seven AND-OR-INVERT 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/rippleblanking 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 Termination Effects CONNECTION DIAGRAM DIP (TOP VIEW) VCC 16 f g a b c d e 15 14 13 12 11 10 9 BCD TO 7-SEGMENT DECODER LOW POWER SCHOTTKY J SUFFIX CERAMIC CASE 620-09 16 1 N SUFFIX PLASTIC CASE 648-08 16 1 D SUFFIX SOIC CASE 751B-03 16 1 1 2 3 4 5 B C LT BI / RBO RBI 6 7 8 D A GND ORDERING INFORMATION SN54LSXXJ SN74LSXXN SN74LSXXD LOGIC DIAGRAM Ceramic Plastic SOIC a LOGIC SYMBOL A 7 1 2 6 3 5 b B INPUT C SN54 / 74LS48 D BLANKING INPUT OR RIPPLE-BLANKING OUTPUT RIPPLE-BLANKING INPUT LAMP-TEST INPUT A B C D LT RBI c OUTPUT a e 13 12 11 10 9 15 14 4 f g FAST AND LS TTL DATA 5-59 b c d e BI/ f g RBO d VCC = PIN 16 GND = PIN 8 SN54/74LS48 PIN NAMES LOADING (Note a) HIGH A, B, C, D RBI LT BI / RBO BCD Inputs Ripple-Blanking (Active Low) Input Lamp-Test (Active Low) Input Blanking Input or RippleBlanking Output (Active Low) Blanking (Active Low) Input BI LOW 0.25 U.L. 0.25 U.L. 0.25 U.L. 0.75 U.L. 2(1) U.L. 0.25 U.L. 3.75 (1.25) U.L. (48) 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 NOTES: a) Unit Load (U.L.) = 40 µA HIGH / 1.6 mA LOW b) Outut current measured at VOUT = 0.5 V Output LOW drive factor is SN54LS / 74LS48: 1.25 U.L. for Military (54), 3.75 U.L. for Commercial (74). 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 NUMERICAL DESIGNATIONS — RESULTANT DISPLAYS TRUTH TABLE SN54 / 74LS48 INPUTS OUTPUTS DECIMAL OR FUNCTION LT RBI D C B A 0 H H L L L 1 H X L L L 2 H X L L H 3 H X L 4 H X 5 H X 6 H 7 BI / RBO a b c d e f g NOTE L H H H H H H H L 1 H H L H H L L L L 1 L H H H L H H L H L H H H H H H H L L H L H L L H L H H L L H H L H L H H H L H H L H H X L H H L H L L H H H H H 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 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. 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 FAST AND LS TTL DATA 5-60 SN54/74LS48 GUARANTEED OPERATING RANGES Symbol Parameter Min Typ Max Unit VCC Supply Voltage 54 74 4.5 4.75 5.0 5.0 5.5 5.25 V TA Operating Ambient Temperature Range 54 74 – 55 0 25 25 125 70 °C 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 74 2.0 6.0 mA IOL Output Current — Low BI / RBO BI / RBO 54 74 1.6 3.2 mA DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified) Limits Symbol Parameter Min VIH Input HIGH Voltage VIL Input LOW Voltage VIK Input Clamp Diode Voltage VOH Output HIGH Voltage 2.4 IO Output Current a to g – 1.3 VOL Output LOW Voltage a to g VOL Output LOW Voltage BI / RBO IIH Input HIGH Current (Except BI / RBO) IIL Typ Max Unit Test Conditions V Guaranteed Input HIGH Voltage for All Inputs V Guaranteed Input LOW Voltage for All Inputs V VCC = MIN, IIN = – 18 mA 4.2 µA VCC = MIN, IOH = – 50 µA, VIN = VIH or U.L. per Truth Table – 2.0 mA VCC = MIN, VO = 0.85 V Input Conditioner as for VOH 2.0 54 0.7 74 0.8 – 1.5 54, 74 0.4 V IOL = 2.0 mA 74 0.5 V IOL = 6.0 mA 54, 74 0.4 V IOL = 1.6 mA 74 0.5 V IOL = 3.2 mA VCC = MIN, VIH = 2.0 V VIL = VIL MAX VCC = MAX, VIH = 2.0 V VIL = VIL MAX 20 µA VCC = MAX, VIN = 2.7 V 0.1 mA VCC = MAX, VIN = 7.0 V 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 38 mA VCC = MAX IOS Short Circuit Current BI/ RBO (Note 1) –2.0 mA VCC = MAX 25 – 0.3 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) Limits Symbol Max Unit tPHL Propagation Delay Time, HIGH-to-LOW Level Output from A Input Parameter 100 ns tPLH Propagation Delay Time, LOW-to-HIGH Level Output from A Input 100 ns tPHL Propagation Delay Time, HIGH-to-LOW Level Output from RBI Input 100 ns tPLH Propagation Delay Time, LOW-to-HIGH Level Output from RBI Input 100 ns Min Typ Test Conditions CL = 15 pF, RL = 4.0 kΩ CL = 15 pF, RL = 6.0 kΩ FAST AND LS TTL DATA 5-61