DM74LS251N

DM74LS251N Datasheet

DM74LS251 3-STATE 1-of-8 Line Data Selector/Multiplexer

Part	Datasheet
DM74LS251N	DM74LS251N (pdf)

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DM74LS251 3-STATE 1-of-8 Line Data Selector/Multiplexer DM74LS251 3-STATE 1-of-8 Line Data Selector/Multiplexer 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. 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. s 3-STATE version of DM74LS151 s Interface directly with system bus s Perform parallel-to-serial conversion s Permit multiplexing from N-lines to one line s Complementary outputs provide true and inverted data s Maximum number of common outputs 129 s Typical propagation delay time D to Y 17 ns s Typical power dissipation 35 mW Ordering Code: Order Number Package Number Package Description DM74LS251M M16A 16-Lead Small Outline Integrated Circuit SOIC , JEDEC MS-012, Narrow DM74LS251N N16E 16-Lead Plastic Dual-In-Line Package PDIP , JEDEC MS-001, 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 Strobe H = HIGH Logic Level L = LOW Logic Level X = Don't Care Z = High Impedance OFF D0, = The level of the respective D input Outputs 2000 Fairchild Semiconductor Corporation DS006415 DM74LS251 Logic Diagram DM74LS251 Absolute Maximum Ratings Note 1 Supply Voltage Input Voltage Operating Free Air Temperature Range 0°C to +70°C Storage Temperature Range −65°C to +150°C 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. Recommended Operating Conditions VCC VIH VIL IOH IOL TA Parameter Supply Voltage HIGH Level Input Voltage LOW Level Input Voltage HIGH Level Output Current LOW Level Output Current Free Air Operating Temperature Electrical Characteristics over recommended operating free air temperature range unless otherwise noted Parameter Conditions Input Clamp Voltage VCC = Min, II = −18 mA HIGH Level Output Voltage VCC = Min, IOH = Max VIL = Max, VIH = Min LOW Level VCC = Min, IOL = Max Output Voltage VIL = Max, VIH = Min IOL = 12 mA, VCC = Min Input Current Max Input Voltage VCC = Max, VI = 7V HIGH Level Input Current VCC = Max, VI = 2.7V LOW Level Input Current

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DM74LS251 3-STATE 1-of-8 Line Data Selector/Multiplexer

DM74LS251 3-STATE 1-of-8 Line Data Selector/Multiplexer

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.

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.
s 3-STATE version of DM74LS151 s Interface directly with system bus s Perform parallel-to-serial conversion s Permit multiplexing from N-lines to one line s Complementary outputs provide true and inverted data s Maximum number of common outputs 129 s Typical propagation delay time D to Y 17 ns s Typical power dissipation 35 mW
Ordering Code:

Order Number Package Number

Package Description

DM74LS251M

M16A
16-Lead Small Outline Integrated Circuit SOIC , JEDEC MS-012, Narrow

DM74LS251N

N16E
16-Lead Plastic Dual-In-Line Package PDIP , JEDEC MS-001, 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

Strobe

H = HIGH Logic Level L = LOW Logic Level X = Don't Care Z = High Impedance OFF D0, = The level of the respective D input

Outputs
2000 Fairchild Semiconductor Corporation DS006415

DM74LS251

Logic Diagram

DM74LS251

Absolute Maximum Ratings Note 1

Supply Voltage

Input Voltage

Operating Free Air Temperature Range 0°C to +70°C

Storage Temperature Range
−65°C to +150°C

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.

Recommended Operating Conditions

VCC VIH VIL IOH IOL TA

Parameter Supply Voltage HIGH Level Input Voltage LOW Level Input Voltage HIGH Level Output Current LOW Level Output Current Free Air Operating Temperature

Electrical Characteristics
over recommended operating free air temperature range unless otherwise noted

Parameter

Conditions

Input Clamp Voltage

VCC = Min, II = −18 mA

HIGH Level

Output Voltage

VCC = Min, IOH = Max

VIL = Max, VIH = Min

LOW Level

VCC = Min, IOL = Max

Output Voltage

VIL = Max, VIH = Min IOL = 12 mA, VCC = Min

Input Current Max Input Voltage

VCC = Max, VI = 7V

HIGH Level Input Current

VCC = Max, VI = 2.7V

LOW Level Input Current

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Datasheet ID: DM74LS251N 513783