Revised March 2000 DM74LS138 • DM74LS139 Decoder/Demultiplexer General Description Features 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. ■ Designed specifically for high speed: 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. ■ Typical propagation delay (3 levels of logic) Memory decoders Data transmission systems ■ DM74LS138 3-to-8-line decoders incorporates 3 enable inputs to simplify cascading and/or data reception ■ DM74LS139 contains two fully independent 2-to-4-line decoders/demultiplexers ■ Schottky clamped for high performance DM74LS138 21 ns DM74LS139 21 ns ■ Typical power dissipation DM74LS138 32 mW DM74LS139 34 mW 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. Ordering Code: Order Number Package Number Package Description DM74LS138M M16A 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow DM74LS138SJ M16D 16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide DM74LS138N N16E 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide DM74LS139M M16A 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow DM74LS139SJ M16D 16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide DM74LS139N N16E 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. © 2000 Fairchild Semiconductor Corporation DS006391 www.fairchildsemi.com DM74LS138 • DM74LS139 Decoder/Demultiplexer August 1986 DM74LS138 • DM74LS139 Connection Diagrams DM74LS138 DM74LS139 Function Tables DM74LS138 DM74LS139 Inputs Enable Inputs Outputs Select Enable G1 G2 (Note 1) C B A YO Y1 Y2 Y3 Y4 Y5 Y6 Y7 Outputs Select G B A Y0 Y1 Y2 Y3 X H X X X H H H H H H H H H X X H H H H L X X X X H H H H H H H H L L L L H H H H L L L L L H H H H H H H L L H H L H H H L L L H H L H H H H H H L H L H H L H H L L H L H H L H H H H H L H H H H H L H L L H H H H H L H H H H H L H L L H H H H L H H H H L H L H H H H H H L H H H L H H L H H H H H H L 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 Logic Diagrams DM74LS138 www.fairchildsemi.com DM74LS139 2 Supply Voltage 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. 7V Input Voltage 7V 0°C to +70°C Operating Free Air Temperature Range −65°C to +150°C Storage Temperature Range DM74LS138 Recommended Operating Conditions Symbol Parameter Min Nom Max 4.75 5 5.25 Units VCC Supply Voltage VIH HIGH Level Input Voltage V VIL LOW Level Input Voltage 0.8 V IOH HIGH Level Output Current −0.4 mA IOL LOW Level Output Current 8 mA TA Free Air Operating Temperature 70 °C 2 V 0 DM74LS138 Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted) Symbol Parameter Conditions Min VI Input Clamp Voltage VCC = Min, II = −18 mA VOH HIGH Level Output Voltage VCC = Min, IOH = Max, VIL = Max, VIH = Min Typ (Note 3) Max −1.5 2.7 3.4 Units V V LOW Level VCC = Min, IOL = Max, VIL = Max, VIH = Min 0.35 0.5 Output Voltage IOL = 4 mA, VCC = Min 0.25 0.4 II Input Current @ Max Input Voltage VCC = Max, VI = 7V 0.1 IIH HIGH Level Input Current VCC = Max, VI = 2.7V 20 µA IIL LOW Level Input Current VCC = Max, VI = 0.4V −0.36 mA IOS Short Circuit Output Current VCC = Max (Note 4) ICC Supply Current VCC = Max (Note 5) VOL −20 V mA −100 mA 10 mA 6.3 Note 3: All typicals are at VCC = 5V, TA = 25°C. 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 = 25°C Symbol Parameter From (Input) Levels To (Output) of Delay RL = 2 kΩ CL = 15 pF Min tPLH Propagation Delay Time LOW-to-HIGH Level Output tPHL Propagation Delay Time HIGH-to-LOW Level Output tPLH Propagation Delay Time LOW-to-HIGH Level Output tPHL Propagation Delay Time HIGH-to-LOW Level Output tPLH Propagation Delay Time LOW-to-HIGH Level Output tPHL Propagation Delay Time HIGH-to-LOW Level Output tPLH Propagation Delay Time LOW-to-HIGH Level Output tPHL Propagation Delay Time HIGH-to-LOW Level Output Max CL = 50 pF Min Units Max Select to Output 2 18 27 ns Select to Output 2 27 40 ns Select to Output 3 18 27 ns Select to Output 3 27 40 ns Enable to Output 2 18 27 ns Enable to Output 2 24 40 ns Enable to Output 3 18 27 ns Enable to Output 3 28 40 ns 3 www.fairchildsemi.com DM74LS138 • DM74LS139 Absolute Maximum Ratings(Note 2) DM74LS138 • DM74LS139 DM74LS139 Recommended Operating Conditions Symbol Parameter Min Nom Max 4.75 5 5.25 Units VCC Supply Voltage VIH HIGH Level Input Voltage V VIL LOW Level Input Voltage 0.8 V IOH HIGH Level Output Current −0.4 mA IOL LOW Level Output Current 8 mA TA Free Air Operating Temperature 70 °C 2 V 0 DM74LS139 Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted) Symbol Parameter Conditions VI Input Clamp Voltage VCC = Min, II = −18 mA VOH HIGH Level VCC = Min, IOH = Max, Output Voltage VIL = Max, VIH = Min VOL LOW Level VCC = Min, IOL = Max Output Voltage VIL = Max, VIH = Min Min 2.7 IOL = 4 mA, VCC = Min Typ (Note 6) Max Units −1.5 V 3.4 V 0.35 0.5 0.25 0.4 V II Input Current @ Max Input Voltage VCC = Max, VI = 7V 0.1 IIH HIGH Level Input Current VCC = Max, VI = 2.7V 20 µA IIL LOW Level Input Current VCC = Max, VI = 0.4V −0.36 mA IOS Short Circuit Output Current VCC = Max (Note 7) ICC Supply Current VCC = Max (Note 8) −20 6.8 mA −100 mA 11 mA Note 6: All typicals are at VCC = 5V, TA = 25°C. 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 = 25°C RL = 2 kΩ From (Input) Symbol Parameter CL = 15 pF To (Output) Min tPLH Propagation Delay Time LOW-to-HIGH Level Output tPHL Propagation Delay Time HIGH-to-LOW Level Output tPLH Propagation Delay Time LOW-to-HIGH Level Output tPHL Propagation Delay Time HIGH-to-LOW Level Output www.fairchildsemi.com Max CL = 50 pF Min Units Max Select to Output 18 27 ns Select to Output 27 40 ns Enable to Output 18 27 ns Enable to Output 24 40 ns 4 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 5 www.fairchildsemi.com 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 www.fairchildsemi.com 6 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. 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