DM74LS251N

Revised March 2000 DM74LS251 3-STATE 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 3-STATE output. The strobe must be at a low logic level to enable these devices. The 3STATE outputs permit direct connection to a common bus. When the strobe input is HIGH, both outputs are in a highimpedance 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 totem-pole outputs. ■ 3-STATE version of DM74LS151 ■ 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: 129 ■ Typical propagation delay time (D to Y): 17 ns ■ Typical power dissipation: 35 mW 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. Ordering Code: Order Number Package Number Package Description DM74LS251M M16A 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow DM74LS251N N16E 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code. Connection Diagram Function Table Inputs Select Outputs Strobe Y W C B A S X X X H Z Z L L L L D0 D0 L L H L D1 D1 L H L L D2 D2 L H H L D3 D3 H L L L D4 D4 H L H L D5 D5 H H L L D6 D6 H H H L D7 D7 H = HIGH Logic Level L = LOW Logic Level X = Don't Care Z = High Impedance (OFF) D0, D1…D7 = The level of the respective D input © 2000 Fairchild Semiconductor Corporation DS006415 www.fairchildsemi.com DM74LS251 3-STATE 1-of-8 Line Data Selector/Multiplexer August 1986 DM74LS251 Logic Diagram www.fairchildsemi.com 2 Supply Voltage Note 1: 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. 7V Input Voltage 7V 0°C to +70°C Operating Free Air Temperature Range −65°C to +150°C Storage Temperature Range Recommended Operating Conditions Symbol Parameter Min Nom Max 4.75 5 5.25 Units VCC Supply Voltage VIH HIGH Level Input Voltage V VIL LOW Level Input Voltage 0.8 V IOH HIGH Level Output Current −2.6 mA IOL LOW Level Output Current 24 mA TA Free Air Operating Temperature 70 °C 2 V 0 Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted) Symbol Parameter Conditions VI Input Clamp Voltage VCC = Min, II = −18 mA VOH HIGH Level VCC = Min, IOH = Max Output Voltage VIL = Max, VIH = Min VOL LOW Level VCC = Min, IOL = Max Output Voltage VIL = Max, VIH = Min Min Typ (Note 2) Max −1.5 2.4 IOL = 12 mA, VCC = Min 3.1 Units V V 0.35 0.5 0.25 0.4 V II Input Current @ Max Input Voltage VCC = Max, VI = 7V 0.1 IIH HIGH Level Input Current VCC = Max, VI = 2.7V 20 µA IIL LOW Level Input Current VCC = Max, VI = 0.4V −0.4 mA IOZH Off-State Output Current with VCC = Max, VO = 2.7V HIGH Level Output Voltage Applied VIH = Min, VIL = Max 20 µA −20 µA IOZL Off-State Output Current with VCC = Max, VO = 0.4V LOW Level Output Voltage Applied VIH = Min, VIL = Max −20 mA IOS Short Circuit Output Current VCC = Max (Note 3) −100 mA ICC1 Supply Current VCC = Max (Note 4) 6.1 10 mA ICC2 Supply Current VCC = Max (Note 5) 7.1 12 mA Note 2: All typicals are at VCC = 5V, TA = 25°C. Note 3: Not more than one output should be shorted at a time, and the duration should not exceed one second. Note 4: ICC1 is measured with the outputs open, STROBE grounded, and all other inputs at 4.5V. Note 5: ICC2 is measured with the outputs open and all inputs at 4.5V. 3 www.fairchildsemi.com DM74LS251 Absolute Maximum Ratings(Note 1) DM74LS251 Switching Characteristics at VCC = 5V and TA = 25°C RL = 667Ω From (Input) Symbol Parameter to (Output) CL = 45 pF Min tPLH Propagation Delay Time LOW-to-HIGH Level Output tPHL Propagation Delay Time HIGH-to-LOW Level Output tPLH Propagation Delay Time LOW-to-HIGH Level Output tPHL Propagation Delay Time HIGH-to-LOW Level Output tPLH Propagation Delay Time LOW-to-HIGH Level Output tPHL Propagation Delay Time HIGH-to-LOW Level Output tPLH Propagation Delay Time LOW-to-HIGH Level Output tPHL Propagation Delay Time HIGH-to-LOW Level Output tPZH Output Enable Time to HIGH Level Output tPZL Output Enable Time to LOW Level Output tPHZ Output Disable Time from HIGH Level Output (Note 6) tPLZ Output Disable Time from LOW Level Output (Note 6) tPZH Output Enable Time to HIGH Level Output tPZL Output Enable Time to LOW Level Output tPHZ Output Disable Time from HIGH Level Output (Note 6) tPLZ Output Disable Time from LOW Level Output (Note 6) A, B, C CL = 150 pF Min Units Max 45 53 ns 45 53 ns 33 38 ns 33 42 ns D to Y 28 35 ns D to Y 28 38 ns D to W 15 25 ns D to W 15 25 ns Strobe to Y 45 60 ns Strobe to Y 40 51 ns Strobe to Y 45 ns Strobe to Y 25 ns Strobe to W 27 40 ns Strobe to W 40 47 ns Strobe to W 55 ns Strobe to W 25 ns (4 Levels) to Y A, B, C (4 Levels) to Y A, B, C (3 Levels) to W A, B, C (3 Levels) to W Note 6: CL = 5 pF www.fairchildsemi.com Max 4 DM74LS251 Physical Dimensions inches (millimeters) unless otherwise noted 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow Package Number M16A 5 www.fairchildsemi.com DM74LS251 3-STATE 1-of-8 Line Data Selector/Multiplexer Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide Package Number N16E Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and Fairchild reserves the right at any time without notice to change said circuitry and specifications. LIFE SUPPORT POLICY FAIRCHILD’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 FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. www.fairchildsemi.com www.fairchildsemi.com 6