DM54LS251/DM74LS251 TRI-STATEÉ Data Selectors/Multiplexers General Description Features These data selectors/multiplexers contain full on-chip binary decoding to select one-of-eight data sources, and feature a strobe-controlled TRI-STATE output. The strobe must be at a low logic level to enable these devices. The TRI-STATE outputs permit direct connection to a common bus. When the strobe input is high, both outputs are in a high-impedance state in which both the upper and lower transistors of each totem-pole output are off, and the output neither drives nor loads the bus significantly. When the strobe is low, the outputs are activated and operate as standard TTL totempole outputs. To minimize the possibility that two outputs will attempt to take a common bus to opposite logic levels, the output control circuitry is designed so that the average output disable time is shorter than the average output enable time. Y Connection Diagram Function Table Y Y Y Y Y Y Y TRI-STATE version of LS151 Interface directly with system bus Perform parallel-to-serial conversion Permit multiplexing from N-lines to one line Complementary outputs provide true and inverted data Maximum number of common outputs 54LS 49 74LS 129 Typical propagation delay time (D to Y) 54LS 17 ns 74LS 17 ns Typical power dissipation 54LS 35 mW 74LS 35 mW Dual-In-Line Package Inputs Select Outputs C B A Strobe S X L L L L H H H H X L L H H L L H H X L H L H L H L H H L L L L L L L L Y W Z D0 D1 D2 D3 D4 D5 D6 D7 Z D0 D1 D2 D3 D4 D5 D6 D7 H e High Logic Level, L e Low Logic Level, X e Don’t Care, Z e High Impedance (Off) D0, D1 . . . D7 e The level of the respective D input TL/F/6415 – 1 Order Number DM54LS251J, DM54LS251W, DM74LS251M or DM74LS251N See NS Package Number J16A, M16A, N16E or W16A TRI-STATEÉ is a registered trademark of National Semiconductor Corporation. C1995 National Semiconductor Corporation TL/F/6415 RRD-B30M105/Printed in U. S. A. DM54LS251/DM74LS251 TRI-STATE Data Selectors/Multiplexers June 1989 Absolute Maximum Ratings (Note) Note: 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. If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Supply Voltage 7V Input Voltage 7V Operating Free Air Temperature Range b 55§ C to a 125§ C DM54LS DM74LS 0§ C to a 70§ C b 65§ C to a 150§ C Storage Temperature Range Recommended Operating Conditions Symbol DM54LS251 Parameter DM74LS251 Units Min Nom Max Min Nom Max 4.5 5 5.5 4.75 5 5.25 VCC Supply Voltage VIH High Level Input Voltage VIL Low Level Input Voltage 0.7 0.8 V IOH High Level Output Current b1 b 2.6 mA IOL Low Level Output Current 24 mA TA Free Air Operating Temperature 70 §C Electrical Characteristics Symbol 2 2 V 12 b 55 125 0 over recommended operating free air temperature range (unless otherwise noted) Parameter Min Typ (Note 1) DM54 2.4 3.4 DM74 2.4 3.1 Conditions Max Units b 1.5 V VI Input Clamp Voltage VCC e Min, II e b18 mA VOH High Level Output Voltage VCC e Min, IOH e Max VIL e Max, VIH e Min Low Level Output Voltage VCC e Min, IOL e Max VIL e Max, VIH e Min DM54 0.25 DM74 0.35 0.5 IOL e 12 mA, VCC e Min DM74 0.25 0.4 VOL V V 0.4 V II Input Current @ Max Input Voltage VCC e Max, VI e 7V IIH High Level Input Current VCC e Max, VI e 2.7V 20 mA IIL Low Level Input Current VCC e Max, VI e 0.4V b 0.4 mA IOZH Off-State Output Current with High Level Output Voltage Applied VCC e Max, VO e 2.7V VIH e Min, VIL e Max 20 mA Off-State Output Current with Low Level Output Voltage Applied VCC e Max, VO e 0.4V VIH e Min, VIL e Max b 20 mA Short Circuit Output Current VCC e Max (Note 2) ICC1 Supply Current VCC e Max (Note 3) 6.1 10 mA ICC2 Supply Current VCC e Max (Note 4) 7.1 12 mA IOZL IOS 0.1 DM54 b 20 b 100 DM74 b 20 b 100 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. Note 3: ICC1 is measured with the outputs open, STROBE grounded, and all other inputs at 4.5V. Note 4: ICC2 is measured with the outputs open and all inputs at 4.5V. 2 mA mA Switching Characteristics Symbol Parameter at VCC e 5V and TA e 25§ C (See Section 1 for Test Waveforms and Output Load) From (Input) to (Output) RL e 667X CL e 45 pF CL e 150 pF Min Max Min Max Units tPLH Propagation Delay Time Low to High Level Output A, B, C (4 Levels) to Y 45 53 ns tPHL Propagation Delay Time High to Low Level Output A, B, C (4 Levels) to Y 45 53 ns tPLH Propagation Delay Time Low to High Level Output A, B, C (3 Levels) to W 33 38 ns tPHL Propagation Delay Time High to Low Level Output A, B, C (3 Levels) to W 33 42 ns tPLH Propagation Delay Time Low to High Level Output D to Y 28 35 ns tPHL Propagation Delay Time High to Low Level Output D to Y 28 38 ns tPLH Propagation Delay Time Low to High Level Output D to W 15 25 ns tPHL Propagation Delay Time High to Low Level Output D to W 15 25 ns tPZH Output Enable Time to High Level Output Strobe to Y 45 60 ns tPZL Output Enable Time to Low Level Output Strobe to Y 40 51 ns tPHZ Output Disable Time from High Level Output (Note 1) Strobe to Y 45 ns tPLZ Output Disable Time from Low Level Output (Note 1) Strobe to Y 25 ns tPZH Output Enable Time to High Level Output Strobe to W 27 40 ns tPZL Output Enable Time to Low Level Output Strobe to W 40 47 ns tPHZ Output Disable Time from High Level Output (Note 1) Strobe to W 55 ns tPLZ Output Disable Time from Low Level Output (Note 1) Strobe to W 25 ns Note 1: CL e 5 pF Logic Diagram TL/F/6415 – 2 3 Physical Dimensions inches (millimeters) 16-Lead Ceramic Dual-In-Line Package (J) Order Number DM54LS251J NS Package Number J16A 4 Physical Dimensions inches (millimeters) (Continued) 16-Lead Small Outline Molded Package (M) Order Number DM74LS251M NS Package Number M16A Molded Dual-In-Line Package (N) Order Number DM74LS251N NS Package Number N16E 5 DM54LS251/DM74LS251 TRI-STATE Data Selectors/Multiplexers Physical Dimensions inches (millimeters) (Continued) 16-Lead Ceramic Flat Package (W) Order Number DM54LS251W NS Package Number W16A LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION. 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