74AHC138; 74AHCT138

3-to-8 line decoder/demultiplexer; inverting

The 74AHC138; 74AHCT138 are high-speed Si-gate CMOS devices and are pin compatible with Low power Schottky TTL (LSTTL). They are specified in compliance with JEDEC standard No. 7A.

The 74AHC138; 74AHCT138 is a 3-to-8 line decoder/demultiplexer. It accepts three binary weighted address inputs (A0, A1 and A2) and, when enabled, provides eight mutually exclusive outputs (Y0 to Y7) that are LOW when selected.

There are three enable inputs: two active LOW (E1 and E2) and one active HIGH (E3). Every output will be HIGH unless E1 and E2 are LOW and E3 is HIGH.

This multiple enable function allows easy parallel expansion of the device to a 1-of-32 (5 lines to 32 lines) decoder with just four 74AHC138; 74AHCT138 devices and one inverter. The 74AHC138; 74AHCT138 can be used as an eight output demultiplexer by using one of the active LOW enable inputs as the data input and the remaining enable inputs as strobes. Unused enable inputs must be permanently tied to their appropriate active HIGH or LOW state.

Features and benefits

  • Balanced propagation delays
  • All inputs have Schmitt-trigger action
  • Demultiplexing capability
  • Multiple input enable for easy expansion
  • Ideal for memory chip select decoding
  • Inputs accepts voltages higher than VCC
  • For 74AHC138 only: operates with CMOS input levels
  • For 74AHCT138 only: operates with TTL input levels
  • ESD protection:
    • HBM JESD22-A114E exceeds 2000 V
    • MM JESD22-A115-A exceeds 200 V
    • CDM JESD22-C101C exceeds 1000 V
  • Multiple package options
  • Specified from -40 °C to +85 °C and from -40 °C to +125 °C


Type numberProduct statusVCC (V)Logic switching levelsOutput drive capability (mA)tpd (ns)Power dissipation considerationsTamb (°C)Rth(j-a) (K/W)Ψth(j-top) (K/W)Rth(j-c) (K/W)Package name
74AHC138BQProduction2.0 - 5.5CMOS± 84.4low-40~1259313.862DHVQFN16
74AHC138DProduction2.0 - 5.5CMOS± 84.4low-40~125939.752SO16
74AHC138PWProduction2.0 - 5.5CMOS± 84.4low-40~1251254.654.7TSSOP16
74AHCT138BQProduction4.5 - 5.5TTL± 84.4low-40~1259313.862DHVQFN16
74AHCT138DProduction4.5 - 5.5TTL± 84.4low-40~125939.752SO16
74AHCT138PWProduction4.5 - 5.5TTL± 84.4low-40~1251254.654.7TSSOP16


Type numberPackagePackage informationReflow-/Wave solderingPackingStatusMarkingOrderable part number, (Ordering code (12NC))
SOT763-1Reel 7” Q1/T1 or Q2/T3ActiveAHC13874AHC138BQ,115
( 9352 855 72115 )
Reel 13" Q1/T1Active74AHC138D74AHC138D,118
( 9352 629 99118 )
Bulk PackActive74AHC138D74AHC138D,112
( 9352 629 99112 )
Reel 13" Q1/T1ActiveAHC13874AHC138PW,118
( 9352 630 00118 )
Bulk PackActiveAHC13874AHC138PW,112
( 9352 630 00112 )
SOT763-1Reel 7” Q1/T1 or Q2/T3ActiveAHT13874AHCT138BQ,115
( 9352 855 73115 )
Reel 13" Q1/T1Active74AHCT138D74AHCT138D,118
( 9352 629 97118 )
Bulk PackActive74AHCT138D74AHCT138D,112
( 9352 629 97112 )
Reel 13" Q1/T1ActiveAHCT13874AHCT138PW,118
( 9352 629 98118 )
Bulk PackActiveAHCT13874AHCT138PW,112
( 9352 629 98112 )

Quality, reliability & chemical content

Type numberOrderable part numberChemical contentRoHS / RHFLeadfree conversion dateEFRIFRMTBF (hour)MSLMSL leadfree
74AHC138BQ74AHC138BQ,11574AHC138BQAlways Pb-free19.60.71.63E511
74AHC138D74AHC138D,11874AHC138Dweek 35, 200419.60.71.63E511
74AHC138D74AHC138D,11274AHC138Dweek 35, 200419.60.71.63E511
74AHC138PW74AHC138PW,11874AHC138PWweek 10, 200519.60.71.63E511
74AHC138PW74AHC138PW,11274AHC138PWweek 10, 200519.60.71.63E511
74AHCT138BQ74AHCT138BQ,11574AHCT138BQAlways Pb-free19.60.71.63E511
74AHCT138D74AHCT138D,11874AHCT138Dweek 35, 200419.60.71.63E511
74AHCT138D74AHCT138D,11274AHCT138Dweek 35, 200419.60.71.63E511
74AHCT138PW74AHCT138PW,11874AHCT138PWweek 10, 200519.60.71.63E511
74AHCT138PW74AHCT138PW,11274AHCT138PWweek 10, 200519.60.71.63E511
Quality and reliability disclaimer

Documentation (9)

File nameTitleTypeDate
74AHC_AHCT1383-to-8 line decoder/demultiplexer; invertingData sheet2020-09-10
ahc138ahc138 IBIS modelIBIS model2013-04-07
ahct138ahct138 IBIS modelIBIS model2013-04-07
SOT763-1plastic, leadless dual in-line compatible thermal enhanced very thin quad flat package; 16 terminals; 0.5 mm pitch; 3.5 mm x 2.5 mm x 1 mm bodyPackage information2020-04-21
SOT109-1plastic, small outline package; 16 leads; 1.27 mm pitch; 9.9 mm x 3.9 mm x 1.75 mm bodyPackage information2021-01-06
SO-SOJ-WAVEFootprint for wave solderingWave soldering2009-10-08
SO-SOJ-REFLOWFootprint for reflow solderingReflow soldering2009-10-08
SSOP-TSSOP-VSO-WAVEFootprint for wave solderingWave soldering2009-10-08
SOT403-1plastic, thin shrink small outline package; 16 leads; 5 mm x 4.4 mm x 1.1 mm bodyPackage information2020-04-21


If you are in need of design/technical support, let us know and fill in the answer form, we'll get back to you shortly.


File nameTitleTypeDate
ahc138ahc138 IBIS modelIBIS model2013-04-07
ahct138ahct138 IBIS modelIBIS model2013-04-07


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