DM54S251/DM74S251 TRI-STATEÉ 1 of 8 Line Data Selector/Multiplexer 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 S151 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 Max no. of common outputs 54S 39 74S 129 Typical propagation delay time (D to Y) 8 ns Typical power dissipation 275 mW Inputs Select C B A 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 Outputs Strobe S Y W H L L L L L L L L 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/6480 – 1 Order Number DM54S251J or DM74S251N See NS Package Number J16A or N16E TRI-STATEÉ is a registered trademark of National Semiconductor Corporation. C1995 National Semiconductor Corporation TL/F/6480 RRD-B30M105/Printed in U. S. A. DM54S251/DM74S251 TRI-STATE 1 of 8 Line Data Selector/Multiplexer 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 5.5V Operating Free Air Temperature Range b 55§ C to a 125§ C DM54S DM74S 0§ C to a 70§ C b 65§ C to a 150§ C Storage Temperature Range Recommended Operating Conditions Symbol DM54S251 Parameter DM74S251 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 0.8 0.8 V IOH High Level Output Current b2 b 6.5 mA IOL Low Level Output Current 20 mA TA Free Air Operating Temperature 70 §C 2 2 V 20 b 55 125 V 0 Electrical Characteristics over recommended operating free air temperature (unless otherwise noted) Symbol Parameter Min Typ (Note 1) DM54 2.4 3.4 DM74 2.4 3.2 Conditions Max Units b 1.2 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 VOL Low Level Output Voltage VCC e Min, IOL e Max VIH e Min, VIL e Max II Input Current @ Max Input Voltage VCC e Max, VI e 5.5V IIH High Level Input VCC e Max, VI e 2.7V 50 mA IIL Low Level Input Current VCC e Max, VI e 0.5V b2 mA IOZH Off-State Output Current with High Level Output Voltage Applied VCC e Max, VO e 2.4 VIH e Min, VIL e Max 50 mA Off-State Output Current with Low Level Output Voltage Applied VCC e Max, VO e 0.5 VIH e Min, VIL e Max b 50 mA Short Circuit Output Current VCC e Max (Note 2) Supply Current VCC e Max (Note 3) IOZL IOS ICC V 1 mA b 40 b 100 DM74 b 40 b 100 Note 2: Not more than one output should be shorted at a time, and the duration should not exceed one second. 2 0.5 DM54 Note 1: All typicals are at VCC e 5V, TA e 25§ C. Note 3: ICC is measured with the outputs open and all inputs at 4.5V. V 55 85 mA mA Switching Characteristics at VCC e 5V and TA e 25§ C (See Section 1 for Test Waveforms and Output Load) RL e 280X From (Input) Symbol Parameter To (Output) CL e 15 pF Min Max CL e 50 pF Min Units Max tPLH Propagation Delay Time Low to High Level Output A, B, or C (4 Levels) to Y 18 21 ns tPHL Propagation Delay Time High to Low Level Output A, B, or C (4 Levels) to Y 19.5 23 ns tPLH Propagation Delay Time Low to High Level Output A, B, or C (3 Levels) to W 15 18 ns tPHL Propagation Delay Time High to Low Level Output A, B, or C (3 Levels) to W 13.5 17 ns tPLH Propagation Delay Time Low to High Level Output D to Y 12 15 ns tPHL Propagation Delay Time High to Low Level Output D to Y 12 15 ns tPLH Propagation Delay Time Low to High Level Output D to W 7 10 ns tPHL Propagation Delay Time High to Low Level Output D to W 7 10 ns tPZH Output Enable Time to High Level Output Strobe to Y 19.5 ns tPZL Output Enable Time to Low Level Output Strobe to Y 21 ns tPHZ Output Disable Time to High Level Output (Note 1) Strobe to Y 8.5 ns tPLZ Output Disable Time to Low Level Output (Note 1) Strobe to Y 14 ns tPZH Output Enable Time to High Level Output Strobe to W 19.5 ns tPZL Output Enable Time to Low Level Output Strobe to W 21 ns tPHZ Output Disable Time to High Level Output (Note 1) Strobe to W 8.5 ns tPLZ Output Disable Time to Low Level Output (Note 1) Strobe to W 14 ns Note 1: CL e 5 pF. 3 Logic Diagram TL/F/6480 – 2 4 Physical Dimensions inches (millimeters) 16-Lead Ceramic Dual-In-Line Package (J) Order Number DM54S251J NS Package Number J16A 5 DM54S251/DM74S251 TRI-STATE 1 of 8 Line Data Selector/Multiplexer Physical Dimensions inches (millimeters) (Continued) 16-Lead Molded Dual-In-Line Package (N) Order Number DM74S251N NS Package Number N16E 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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