SN54/74LS147 SN54/74LS148 SN54/74LS748 10-LINE-TO-4-LINE AND 8-LINE-TO-3-LINE PRIORITY ENCODERS The SN54 / 74LS147 and the SN54/ 74LS148 are Priority Encoders. They provide priority decoding of the inputs to ensure that only the highest order data line is encoded. Both devices have data inputs and outputs which are active at the low logic level. The LS147 encodes nine data lines to four-line (8-4-2-1) BCD. The implied decimal zero condition does not require an input condition because zero is encoded when all nine data lines are at a high logic level. The LS148 encodes eight data lines to three-line (4-2-1) binary (octal). By providing cascading circuitry (Enable Input EI and Enable Output EO) octal expansion is allowed without needing external circuitry. The SN54 / 74LS748 is a proprietary Motorola part incorporating a built-in deglitcher network which minimizes glitches on the GS output. The glitch occurs on the negative going transition of the EI input when data inputs 0 – 7 are at logical ones. The only dc parameter differences between the LS148 and the LS748 are that (1) Pin 10 (input 0) has a fan-in of 2 on the LS748 versus a fan-in of 1 on the LS148; (2) Pins 1, 2, 3, 4, 11, 12 and 13 (inputs 1, 2, 3, 4, 5, 6, 7) have a fan-in of 3 on the LS748 versus a fan-in of 2 on the LS148. The only ac difference is that tPHL from EI to EO is changed from 40 to 45 ns. SN54 / 74LS147 (TOP VIEW) OUTPUT INPUTS 10-LINE-TO-4-LINE AND 8-LINE-TO-3-LINE PRIORITY ENCODERS LOW POWER SCHOTTKY J SUFFIX CERAMIC CASE 620-09 16 1 N SUFFIX PLASTIC CASE 648-08 16 1 OUTPUT VCC NC D 3 2 1 9 A 16 15 14 13 12 11 10 9 D 3 2 1 9 16 1 4 A ORDERING INFORMATION 5 6 7 8 C 1 2 3 4 5 6 7 8 4 5 6 7 8 C B GND INPUTS B SN54LSXXXJ SN74LSXXXN SN74LSXXXD OUTPUTS SN54 / 74LS148 SN54 / 74LS748 (TOP VIEW) INPUTS OUTPUTS OUTPUT VCC EO GS 3 2 1 0 A0 16 15 14 13 12 11 10 9 EO GS 3 2 1 0 4 A0 5 6 7 EI A2 A1 7 A1 1 2 3 4 5 6 4 5 6 7 E1 A2 INPUTS D SUFFIX SOIC CASE 751B-03 8 GND OUTPUTS FAST AND LS TTL DATA 5-245 Ceramic Plastic SOIC SN54/74LS147 • SN54/74LS148 • SN54/74LS748 SN54 / 74LS148 SN54 / 74LS748 FUNCTION TABLE SN54 / 74LS147 FUNCTION TABLE INPUTS OUTPUTS INPUTS OUTPUTS 1 2 3 4 5 6 7 8 9 D C B A EI 0 1 2 3 4 5 6 7 A2 A1 A0 GS EO H X X X X X X X X L H X X X X X X X L H H X X X X X X L H H H X X X X X L H H H H X X X X L H H H H H X X X L H H H H H H X X L H H H H H H H X L H H H H H H H H L H H H H H H H H H L L H H H H H H H H H H L L L L H H H H H H L L H H L L H H L H L H L H L H L H L L L L L L L L L X H X X X X X X X L X H X X X X X X L H X H X X X X X L H H X H X X X X L H H H X H X X X L H H H H X H X X L H H H H H X H X L H H H H H H X H L H H H H H H H H H L L L L H H H H H H L L H H L L H H H H L H L H L H L H H H L L L L L L L L H L H H H H H H H H H = HIGH Logic Level, L = LOW Logic Level, X = Irrelevant FUNCTIONAL BLOCK DIAGRAMS 1 (11) (10) 0 (15) EO (12) 2 (9) (11) (14) 1 A (13) GS (12) 3 2 (8) A0 (1) (13) 4 3 (7) 5 (2) B 4 8 9 (7) (2) (3) 6 7 (1) A1 5 (4) (3) (6) 6 C (4) (5) (6) 7 (14) (10) A2 (5) D EI SN54 / 74LS147 SN54 / 74LS148 FAST AND LS TTL DATA 5-246 SN54/74LS147 • SN54/74LS148 • SN54/74LS748 FUNCTIONAL BLOCK DIAGRAMS (continued) G31 (10) 0 G13 (15) EO (14) (11) 1 GS G2 G29 G9 (12) 2 (9) G3 A0 (13) 3 G18 G4 4 G10 (1) G5 5 A1 G23 G6 6 (7) G11 (2) G12 (3) G7 (4) (6) 7 A2 G8 G28 (5) EI G1 SN54 / 74LS748 FAST AND LS TTL DATA 5-247 SN54/74LS147 • SN54/74LS148 • SN54/74LS748 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 54, 74 – 0.4 mA IOL Output Current — Low 54 74 4.0 8.0 mA DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified) Limits Symbol Parameter VIH Input HIGH Voltage VIL Input LOW Voltage VIK Input Clamp Diode Voltage VOH Output HIGH Voltage VOL Output LOW Voltage IIH Min Typ Max Unit 2.0 54 0.7 74 0.8 – 0.65 – 1.5 Test Conditions V Guaranteed Input HIGH Voltage for All Inputs V Guaranteed Input LOW Voltage for All Inputs V VCC = MIN, IIN = – 18 mA 54 2.5 3.5 V 74 2.7 3.5 V VCC = MIN, IOH = MAX, VIN = VIH or VIL per Truth Table VCC = VCC MIN, VIN = VIL or VIH per Truth Table 54, 74 0.25 0.4 V IOL = 4.0 mA 74 0.35 0.5 V IOL = 8.0 mA µA VCC = MAX, VIN = 2.7 V mA VCC = MAX, VIN = 7.0 V mA VCC = MAX, VIN = 0.4 V – 100 mA VCC = MAX Input HIGH Current All Others Input 0 (LS748) Inputs 1 – 7 (LS148) Inputs 1 – 7 (LS748) 20 40 40 60 All Others Input 0 (LS748) Inputs 1 – 7 (LS148) Inputs 1 – 7 (LS748) 0.1 0.2 0.2 0.3 IIL Input LOW Current All Others Input 0 (LS748) Inputs 1 – 7 (LS148) Inputs 1 – 7 (LS748) IOS Short Circuit Current (Note 1) ICCH Power Supply Current Output HIGH 17 mA VCC = MAX, All Inputs = 4.5 V ICCL Output LOW 20 mA VCC = MAX, Inputs 7 & E1 = GND All Other Inputs = 4.5 V – 0.4 – 0.8 – 0.8 – 1.2 – 20 Note 1: Not more than one output should be shorted at a time, nor for more than 1 second. FAST AND LS TTL DATA 5-248 SN54/74LS147 • SN54/74LS148 • SN54/74LS748 AC CHARACTERISTICS (VCC = 5.0 V, TA = 25°C) SN54 / 74LS147 Symbol tPLH From (Input) To (Output) Any Any tPHL tPLH Any Any tPHL Limits Waveform Min Typ Max In-phase output 12 18 12 18 Out-of-phase output 21 33 15 23 Unit Test Conditions ns CL = 15 pF, RL = 2.0 kΩ ns SN54 / 74LS148 SN54 / 74LS748 Symbol tPLH From (Input) To (Output) 1 thru 7 A0, A1, or A2 tPHL tPLH 1 thru 7 A0, A1, or A2 tPHL tPLH 0 thru 7 EO tPHL tPLH 0 thru 7 GS tPHL tPLH EI A0, A1, or A2 tPHL tPLH EI GS tPHL tPLH tPHL EI EO Limits Waveform Min Typ Max In-phase output 14 18 15 25 Out-of-phase output 20 36 16 29 Out-of-phase output 7.0 18 25 40 In-phase output 35 55 Unit Test Conditions ns ns ns ns 9.0 21 In-phase output 16 25 12 25 In-phase output 12 17 14 36 12 21 28 30 40 45 CL = 15 pF, RL = 2.0 kΩ ns ns In-phase output FAST AND LS TTL DATA 5-249 ns (LS148) (LS748) Case 751B-03 D Suffix 16-Pin Plastic SO-16 -A- "! ! " " ! " # 1 %# ) ! !" $ !" 8 C -T- D M K " ! #! J F ! Case 648-08 N Suffix 16-Pin Plastic R X 45° G " ! ) #! P ! " " 9 -B- ! 16 & ! ! ° ° ° ° ( ( ( ( "! ! " " ! ! ' " " ! ' ! " # & -A- 16 9 1 8 ! ! $ ! B # ) " ! " # ) !" $ !" ) F L C S -T- K H G M J D " Case 620-09 J Suffix 16-Pin Ceramic Dual In-Line -A- ! ! ! ! ° ° ° ° "! ! " 16 " ) " L K M N J G D " $ " $ ! " " ! ! FAST AND LS TTL DATA 5-250 & # ) !" $ !" ) -T $ " " C F & 8 E ! ! ! " " -B1 & 9 * * ! ! ! ! * * ! ° ° ! ° ° Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. “Typical” parameters can and do vary in different applications. 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ASIA PACIFIC: Motorola Semiconductors H.K. Ltd.; Silicon Harbour Center, No. 2 Dai King Street, Tai Po Industrial Estate, Tai Po, N.T., Hong Kong. ◊ FAST AND LS TTL DATA 5-251