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DM74LS138 * DM74LS139 Decoder/Demultiplexer
August 1986 Revised March 2000
DM74LS138 * DM74LS139 Decoder/Demultiplexer
General Description
These Schottky-clamped circuits are designed to be used in high-performance memory-decoding or data-routing applications, requiring very short propagation delay times. In high-performance memory systems these decoders can be used to minimize the effects of system decoding. When used with high-speed memories, the delay times of these decoders are usually less than the typical access time of the memory. This means that the effective system delay introduced by the decoder is negligible. The DM74LS138 decodes one-of-eight lines, based upon the conditions at the three binary select inputs and the three enable inputs. Two active-low and one active-high enable inputs reduce the need for external gates or inverters when expanding. A 24-line decoder can be implemented with no external inverters, and a 32-line decoder requires only one inverter. An enable input can be used as a data input for demultiplexing applications. The DM74LS139 comprises two separate two-line-to-fourline decoders in a single package. The active-low enable input can be used as a data line in demultiplexing applications. All of these decoders/demultiplexers feature fully buffered inputs, presenting only one normalized load to its driving circuit. All inputs are clamped with high-performance Schottky diodes to suppress line-ringing and simplify system design.
Features
s Designed specifically for high speed: Memory decoders Data transmission systems s DM74LS138 3-to-8-line decoders incorporates 3 enable inputs to simplify cascading and/or data reception s DM74LS139 contains two fully independent 2-to-4-line decoders/demultiplexers s Schottky clamped for high performance s Typical propagation delay (3 levels of logic) DM74LS138 DM74LS139 DM74LS138 DM74LS139 21 ns 21 ns 32 mW 34 mW
s Typical power dissipation
Ordering Code:
Order Number DM74LS138M DM74LS138SJ DM74LS138N DM74LS139M DM74LS139SJ DM74LS139N Package Number M16A M16D N16E M16A M16D N16E Package Description 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow 16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow 16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide 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.
(c) 2000 Fairchild Semiconductor Corporation
DS006391
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DM74LS138 * DM74LS139
Connection Diagrams
DM74LS138 DM74LS139
Function Tables
DM74LS138 Inputs Enable X L H H H H H H H H H X L L L L L L L L Select XXX XXX LLL LLH LHL LHH HLL HLH HHL HHH H H L H H H H H H H H H H L H H H H H H H H H H L H H H H H Outputs Inputs Enable G H L L L L H H H H H H H L H H H H H H H H H H L H H H H H H H H H H L
H = HIGH Level L = LOW Level X = Don't Care Note 1: G2 = G2A + G2B
DM74LS139 Outputs Y0 H L H H H Y1 H H L H H Y2 H H H L H Y3 H H H H L
Select B X L L H H A X L H L H
G1 G2 (Note 1) C B A YO Y1 Y2 Y3 Y4 Y5 Y6 Y7 H H H H H L H H H H H H H H H H L H H H
Logic Diagrams
DM74LS138 DM74LS139
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DM74LS138 * DM74LS139
Absolute Maximum Ratings(Note 2)
Supply Voltage Input Voltage Operating Free Air Temperature Range Storage Temperature Range 7V 7V 0C to +70C -65C to +150C
Note 2: 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 tables are not guaranteed at the absolute maximum ratings. The "Recommended Operating Conditions" table will define the conditions for actual device operation.
DM74LS138 Recommended Operating Conditions
Symbol VCC VIH VIL IOH IOL TA Supply Voltage HIGH Level Input Voltage LOW Level Input Voltage HIGH Level Output Current LOW Level Output Current Free Air Operating Temperature 0 Parameter Min 4.75 2 0.8 -0.4 8 70 Nom 5 Max 5.25 Units V V V mA mA C
DM74LS138 Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted) Symbol VI VOH VOL II IIH IIL IOS ICC Parameter Input Clamp Voltage HIGH Level Output Voltage LOW Level Output Voltage Input Current @ Max Input Voltage HIGH Level Input Current LOW Level Input Current Short Circuit Output Current Supply Current Conditions VCC = Min, II = -18 mA VCC = Min, IOH = Max, VIL = Max, VIH = Min VCC = Min, IOL = Max, VIL = Max, VIH = Min IOL = 4 mA, VCC = Min VCC = Max, VI = 7V VCC = Max, VI = 2.7V VCC = Max, VI = 0.4V VCC = Max (Note 4) VCC = Max (Note 5) -20 6.3 2.7 3.4 0.35 0.25 0.5 0.4 0.1 20 -0.36 -100 10 Min Typ (Note 3) Max -1.5 Units V V V mA A mA mA mA
Note 3: All typicals are at VCC = 5V, TA = 25C. Note 4: Not more than one output should be shorted at a time, and the duration should not exceed one second. Note 5: ICC is measured with all outputs enabled and OPEN.
DM74LS138 Switching Characteristics
at VCC = 5V and TA = 25C From (Input) Symbol Parameter To (Output) Levels of Delay CL = 15 pF Min tPLH tPHL tPLH tPHL tPLH tPHL tPLH tPHL Propagation Delay Time LOW-to-HIGH Level Output Propagation Delay Time HIGH-to-LOW Level Output Propagation Delay Time LOW-to-HIGH Level Output Propagation Delay Time HIGH-to-LOW Level Output Propagation Delay Time LOW-to-HIGH Level Output Propagation Delay Time HIGH-to-LOW Level Output Propagation Delay Time LOW-to-HIGH Level Output Propagation Delay Time HIGH-to-LOW Level Output Select to Output Select to Output Select to Output Select to Output Enable to Output Enable to Output Enable to Output Enable to Output 2 2 3 3 2 2 3 3 Max 18 27 18 27 18 24 18 28 RL = 2 k CL = 50 pF Min Max 27 40 27 40 27 40 27 40 ns ns ns ns ns ns ns ns Units
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DM74LS138 * DM74LS139
DM74LS139 Recommended Operating Conditions
Symbol VCC VIH VIL IOH IOL TA Supply Voltage HIGH Level Input Voltage LOW Level Input Voltage HIGH Level Output Current LOW Level Output Current Free Air Operating Temperature 0 Parameter Min 4.75 2 0.8 -0.4 8 70 Nom 5 Max 5.25 Units V V V mA mA C
DM74LS139 Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted) Symbol VI VOH VOL Parameter Input Clamp Voltage HIGH Level Output Voltage LOW Level Output Voltage II IIH IIL IOS ICC Input Current @ Max Input Voltage HIGH Level Input Current LOW Level Input Current Short Circuit Output Current Supply Current Conditions VCC = Min, II = -18 mA VCC = Min, IOH = Max, VIL = Max, VIH = Min VCC = Min, IOL = Max VIL = Max, VIH = Min IOL = 4 mA, VCC = Min VCC = Max, VI = 7V VCC = Max, VI = 2.7V VCC = Max, VI = 0.4V VCC = Max (Note 7) VCC = Max (Note 8) -20 6.8 2.7 3.4 0.35 0.25 0.5 0.4 0.1 20 -0.36 -100 11 mA A mA mA mA Min Typ (Note 6) Max -1.5 Units V V
V
Note 6: All typicals are at VCC = 5V, TA = 25C. Note 7: Not more than one output should be shorted at a time, and the duration should not exceed one second. Note 8: ICC is measured with all outputs enabled and OPEN.
DM74LS139 Switching Characteristics
at VCC = 5V and TA = 25C From (Input) Symbol Parameter To (Output) CL = 15 pF Min tPLH tPHL tPLH tPHL Propagation Delay Time LOW-to-HIGH Level Output Propagation Delay Time HIGH-to-LOW Level Output Propagation Delay Time LOW-to-HIGH Level Output Propagation Delay Time HIGH-to-LOW Level Output Select to Output Select to Output Enable to Output Enable to Output Max 18 27 18 24 RL = 2 k CL = 50 pF Min Max 27 40 27 40 ns ns ns ns Units
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DM74LS138 * DM74LS139
Physical Dimensions inches (millimeters) unless otherwise noted
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow Package Number M16A
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DM74LS138 * DM74LS139
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide Package Number M16D
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DM74LS138 * DM74LS139 Decoder/Demultiplexer
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: 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. 7 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. www.fairchildsemi.com
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