SN74ALS251 1-of-8 Data Selectors/Multiplexers With 3-State Outputs |

SN74ALS251 (ACTIVE) 1-of-8 Data Selectors/Multiplexers With 3-State Outputs



These data selectors/multiplexers contain full binary decoding to select one-of-eight data sources and feature controlled complementary 3-state outputs.

The 3-state outputs can interface with and drive data lines of bus-organized systems. With all but one of the common outputs disabled (at the high-impedance state), the low impedance of the signal-enabled output drives the bus line to a high or low logic level. Both outputs are controlled by the output-enable (OE\) input. The outputs are disabled when is high.

The SN54ALS251 is characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ALS251 is characterized for operation from 0°C to 70°C.



D0, D1,...D7 = the level of the respective D input


  • 3-State Version of the ´ALS151
  • 3-State Outputs Interface Directly With System Bus
  • Perform Parallel-to-Serial Conversion
  • Complementary Outputs Provide True and Inverted Data
  • Package Options Include Plastic Small-Outline (D) Packages, Ceramic Chip Carriers (FK), and Standard Plastic (N) and Ceramic (J) 300-mil DIPs


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Part number Order Function Technology Family VCC (Min) (V) VCC (Max) (V) Channels (#) Voltage (Nom) (V) F @ nom voltage (Max) (MHz) ICC @ nom voltage (Max) (mA) tpd @ nom Voltage (Max) (ns) Configuration Type IOL (Max) (mA) IOH (Max) (mA) Rating Operating temperature range (C) Package Group Package size: mm2:W x L (PKG) Bits (#) Digital input leakage (Max) (uA) ESD CDM (kV) ESD HBM (kV)
SN74ALS251 Order now Encoder
ALS     4.5     5.5     1     5     75     14     24     8:1     3-State Output     24     -2.6       0 to 70     PDIP | 16
SOIC | 16
SO | 16    
See datasheet (PDIP)
16SO: 80 mm2: 7.8 x 10.2 (SO | 16)
16SOIC: 59 mm2: 6 x 9.9 (SOIC | 16)    
8     5     0.75     2    
SN54ALS251 Samples not available Encoder/Multiplexer     ALS     4.5     5.5     1     5     75     14     24     8:1     3-State Output     24/-2.6       Military     -55 to 125     CDIP | 16
CFP | 16
LCCC | 20    
See datasheet (CDIP)
See datasheet (CFP)
20LCCC: 79 mm2: 8.89 x 8.89 (LCCC | 20)    
8     5     0.75     2