Diodes 74AHC138 User Manual
Description, Features, Pin assignments
74AHC138
Document number: DS35482 Rev. 2 - 2
1 of 10
June 2013
© Diodes Incorporated
Preliminary
74AHC138
3-TO-8 LINE DECODER DEMULTIPLEXER
Description
The 74AHC138 is an advanced high speed CMOS device.
The device accepts a three bit binary weighted address on input
pins A0, A1 and A2 and when enabled will produce one active low
output with the remaining seven being high.
There are two active LOW enable inputs E1 and E2, and one active
HIGH enable input E3. The disabled device state results in all
outputs being high. The enable state occurs with E 1 and E 2
asserted low and E3 asserted high.
The multiple enable lines allow for the parallel expansion of
decoders to create 4-to-16 line versions with no additional parts and
5-to-32 versions with the addition of a single inverter.
Features
• Wide Supply Voltage Range from 2.0 V to 5.5 V
• Sinks or sources 8mA at Vcc = 4.5V
• CMOS low power consumption
• Schmitt Trigger Action at All Inputs
• Inputs accept up to 5.5 V
• ESD Protection Tested per JESD 22
Exceeds 200-V Machine Model (A115-A)
Exceeds 2000-V Human Body Model (A114-A)
Exceeds 1000-V Charged Device Model (C101C)
• Latch-Up Exceeds 250mA per JESD 78, Class II
• SO16 Available in “Green” Molding Compound
(no Br, Sb)
•
Lead-Free Finish; RoHS Compliant (Notes 1 & 2)
Pin Assignments
Applications
• Memory chip select decoding
• Demultiplexing
• Single line peripheral control
• Allow simple serial bit streams from a microcontroller to control
as many peripheral lines as needed.
Notes:
1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
2. Se information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green" and Lead-free.
3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl)
and < 1000 ppm antimony compounds.
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