SN74ALS138ADRG4 Texas Instruments Integrated Circuit (Small Outline Packages) In Stock
The SN74ALS138ADRG4 is a 3-to-8 line decoder/demultiplexer in the Advanced Low-power Schottky logic family, featuring two active-low and one active-high enable inputs in a 16-pin SOIC package. It operates from a 5 V supply and drives up to 8 mA per output. Suitable for address decoding, memory chip-select generation, and digital signal routing in high-speed logic designs.
- Manufacturer
- Texas Instruments
- Package
- Small Outline Packages
- Pin Count
- 16
- Lifecycle
- OBSOLETE
- Datasheet
- SN74ALS138ADRG4 Datasheet PDF
- Category
- Integrated Circuit
- Price
- From $0.6250(MOQ 1)
- Temp Range
- ?°C to 70.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of SN74ALS138ADRG4?
- 3-to-8 line decoder with active-low outputs
- Two active-low and one active-high enable inputs for cascading
- ALS Schottky-clamped process for fast propagation delays
- 50 pF rated load capacitance per output
- RoHS-compliant 16-pin SOIC (R-PDSO-G16) package
- 8 mA maximum output sink current per line
What is SN74ALS138ADRG4 used for?
The SN74ALS138ADRG4 is widely used in digital address decoding to select one of up to eight memory banks or peripheral chips from a 3-bit address bus. Its three enable inputs allow straightforward cascading to expand decoding capacity without extra glue logic. The device also serves as a demultiplexer in data-routing and testing circuits where precise channel selection is required.
What are the specifications of SN74ALS138ADRG4?
| Pbfree Code | Yes |
| YTEOL | 0 |
| Additional Feature | 2 ACTIVE-LOW AND 1 ACTIVE-HIGH ENABLE INPUT, SCHOTTKY-CLAMPED FOR HIGH PERFORMANCE |
| Family | ALS |
| Input Conditioning | STANDARD |
| JESD-30 Code | R-PDSO-G16 |
| JESD-609 Code | e4 |
| Load Capacitance (CL) | 50pF |
| Logic IC Type | 3-LINE TO 8-LINE DECODER |
| Max I(ol) | 0.008A |
| Number of Bits | 8 |
| Number of Functions | 1 |
| Output Polarity | INVERTED |
| Package Body Material | PLASTIC/EPOXY |
| Package Equivalence Code | SOP16,.25 |
| Package Shape | RECTANGULAR |
| Package Style | SMALL OUTLINE |
| Packing Method | TR |
| Peak Reflow Temperature (Cel) | 260 |
| Power Supply Current-Max (ICC) | 10mA |
| Prop. Delay@Nom-Sup | 22ns |
| Propagation Delay (tpd) | 22ns |
| Qualification Status | Not Qualified |
| Supply Voltage-Max (Vsup) | 5.5V |
| Supply Voltage-Min (Vsup) | 4.5V |
| Supply Voltage-Nom (Vsup) | 5V |
| Surface Mount | YES |
| Technology | TTL |
| Temperature Grade | COMMERCIAL |
| Terminal Finish | Nickel/Palladium/Gold (Ni/Pd/Au) |
| Terminal Form | GULL WING |
| Terminal Pitch | 1.27mm |
| Terminal Position | DUAL |
| Time@Peak Reflow Temperature-Max (s) | 30 |
| Package | Small Outline Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| Moisture Sensitivity Level | MSL 1 |
| ECCN | EAR99 |
| HTS Code | 8542.39.00.01 |
Where can I find the SN74ALS138ADRG4 datasheet?
SN74ALS138ADRG4 Datasheet DownloadOfficial datasheet from Texas Instruments
What are equivalent replacements for SN74ALS138ADRG4?
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
How many output lines can the SN74ALS138ADRG4 drive simultaneously, and what is the maximum sink current per output?
The SN74ALS138ADRG4 decodes a 3-bit address to activate exactly 1 of its 8 active-low outputs at a time. Each output can sink up to 8 mA, making it compatible with standard TTL and CMOS loads, and the 50 pF rated load capacitance ensures reliable switching in most PCB trace environments.
How do the enable inputs of the SN74ALS138ADRG4 work, and when would a designer use them for cascading?
The device provides two active-low enable pins (G1-bar, G2-bar) and one active-high enable pin (G), all of which must be asserted simultaneously for any output to go low. By tying the G pin of one device to a higher-order address bit and chaining G1-bar or G2-bar, designers can cascade multiple SN74ALS138A devices to decode 4-bit or wider address spaces with no additional gates.
When is the SN74ALS138ADRG4 the right choice compared to newer CMOS decoders such as the 74HC138?
The ALS family offers propagation delays typically under 10 ns at 5 V, faster than the 74HC138's ~15 ns at the same voltage, making SN74ALS138ADRG4 preferable in legacy 5 V backplane or bus-interface designs where timing margins are tight. However, the HC variant draws less static power, so ALS is best justified when switching speed matters more than quiescent current in battery-powered equipment.
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About Texas Instruments
Texas Instruments (TI) is a global semiconductor company headquartered in Dallas, Texas. TI designs and manufactures analog and embedded processing chips used in industrial, automotive, consumer, communications, and enterprise systems.
More from Texas Instruments
| Qty. | Unit Price | Ext. Price |
|---|---|---|
| 1+ | $0.7500 | $0.75 |
| 8+ | $0.6250 | $5.00 |
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