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Texas Instruments SN74AS158DR
- Part No.:
- SN74AS158DR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74AS158DR.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:17,500
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Product details
Overview
SN74AS158DR from Texas Instruments is a high-speed 4-bit dual 2-line-to-1 data selector/multiplexer with inverted output logic, designed for TTL-compatible digital systems. It features buffered inputs/outputs, 16-pin SOIC (D) package, 0°C to 70°C operating range, and delivers sub-11 ns propagation delay (tPHL/tPLH) at VCC = 5 V with CL = 50 pF - enabling precise signal routing in bus arbitration and address/data path selection.
For engineers reviewing the SN74AS158DR datasheet, SN74AS158DR pinout, SN74AS158DR application, or SN74AS158DR equivalent, key selection criteria include its inverted-output architecture (vs. true-output SN74AS157DR), AS-series speed-power tradeoff, 20 mA sink capability, and compatibility with legacy 74-series logic families in industrial control and test equipment designs.
Technical Context
The SN74AS158DR implements a dual 2:1 multiplexer function with independent A/B select control per 4-bit channel and a global enable (G) input. Its internal structure includes inverters and drivers that route selected inputs to inverted outputs - minimizing propagation delay versus non-inverting variants like SN74AS157DR.
It operates strictly as a totem-pole output device (no 3-state), supports standard TTL voltage thresholds (VIH = 2 V, VIL = 0.8 V), and draws ICC = 15.6–22.5 mA at VCC = 5.5 V - reflecting the higher drive strength and speed of the AS (Advanced Schottky) family compared to ALS or LS series.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Function | 4-bit dual 2-line-to-1 multiplexer with inverted outputs (Y = NOT[(A/B) ? A : B]) |
| Propagation Delay | tPHL/tPLH ≤ 10.5 ns max (A/B → Y) at VCC = 4.5–5.5 V, CL = 50 pF - enables <100 MHz toggle rates in synchronous paths |
| Output Drive | IOL = 20 mA (min), IOH = −2 mA - drives heavy capacitive loads or multiple TTL inputs without buffering |
| Supply Range | VCC = 4.5 V to 5.5 V - compatible with regulated 5 V rails; absolute max 7 V prevents latch-up under transient overvoltage |
| Operating Temp | 0°C to 70°C - qualified for commercial-grade embedded systems, not extended/military temperature ranges |
| Package | 16-pin SOIC (D), 3.9 mm width, RoHS-compliant NIPDAU lead finish, MSL Level-1 - suitable for automated SMT assembly |
Pinout & Package
SN74AS158DR uses a 16-pin small-outline integrated circuit (SOIC-D) package with 1.27 mm pitch, 3.9 mm body width, and 1.75 mm height. Pin 1 is marked by a beveled corner or notch; the device has no internal connections on pins 3 and 11 (NC).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 4, 5, 6, 7, 10, 11, 13, 14 | Data Inputs (1A, 1B, 2A, 2B, 3A, 3B, 4A, 4B, A/B) | Two 4-bit input groups (A/B select line common to all channels); A/B = L selects A-inputs, H selects B-inputs |
| 3, 11 | No Connect (NC) | Unbonded die pads - must remain unconnected on PCB; no pull-up/down or routing required |
| 8 | GND | Ground reference for all logic and output stages; requires low-inductance connection to system ground plane |
| 9, 12, 15, 16 | Outputs (1Y, 2Y, 3Y, 4Y) | Inverted multiplexed outputs - Yn = NOT[An if A/B=L else Bn]; fan-out ≥ 20 TTL loads |
| 16 | VCC | +5 V supply; decoupling capacitor (0.1 µF ceramic) required within 10 mm of pin for noise suppression |
| 15 | G (Strobe/Enable) | Active-low global enable - G = L enables outputs; G = H forces all Y outputs high (inverted disable state) |
Key Features
| Feature | Design Value |
|---|---|
| Inverted Output Architecture | Reduces propagation delay by eliminating post-mux inversion stage - tPHL/tPLH up to 3× faster than comparable ALS variants |
| AS-Series Speed Optimization | Delivers 1–10.5 ns switching at 20 mA drive - bridges gap between LS power efficiency and F/FAST speed in space-constrained designs |
| Buffered I/O Structure | Input hysteresis and output totem-pole drivers ensure noise immunity and stable logic levels across full load range (0–20 mA) |
| TTL-Compatible Interface | Meets standard VIH/VIL and VOH/VOL specs - interoperable with 74LS, 74ALS, and microcontroller GPIO without level-shifting |
Applications
| Bus Arbitration Logic | Address/Data Path Selection |
|---|---|
Use Scenario: Resolving contention between two CPU peripherals sharing a common data bus in an 8-bit microcontroller system. IC Role / Device Role / Timing Role: SN74AS158DR selects between peripheral A and B address/data lines under CPU control, with inverted outputs directly driving bus transceivers. Use Value: Sub-11 ns delay ensures setup/hold timing margins are preserved at 8 MHz bus clock rates without added wait states. | Use Scenario: Routing instruction fetch addresses from ROM or RAM banks based on memory-mapped I/O configuration bits. IC Role / Device Role / Timing Role: SN74AS158DR acts as a bank-select multiplexer, where A/B input selects between two 4-bit address segments routed to the ALU. Use Value: High sink current (20 mA) allows direct interface to address latch inputs without external buffers, reducing component count. |
| Test Equipment Signal Routing | Digital Instrumentation Multiplexing |
Use Scenario: Switching calibration reference signals between DUT channels in automated test fixtures with tight timing budgets. IC Role / Device Role / Timing Role: SN74AS158DR routes precision analog reference paths via digitally controlled logic-level switches (driving external analog mux enable lines). Use Value: Guaranteed 0.5 V VOL at 20 mA ensures clean low-state signaling to downstream CMOS switches, preventing false triggering. | Use Scenario: Consolidating sensor data streams (e.g., thermocouple, pressure, humidity) onto a single ADC input in embedded monitoring hardware. IC Role / Device Role / Timing Role: SN74AS158DR selects one of two 4-bit parallel sensor outputs under microcontroller command before serial conversion. Use Value: Inverted output logic simplifies control firmware - active-high select lines map directly to A/B and G pins without software inversion. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar data selector applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AS157DR | True-output variant (non-inverting); identical pinout, speed, and drive specs | Required where downstream logic expects non-inverted data; adds 1–2 ns delay due to explicit inversion stage | Select when system timing budget allows extra delay and output polarity must match source data |
| SN74ALS158N | ALS-family version: slower (max 22 ns), lower ICC (5–10 mA), PDIP-16 package only | Suitable for cost-sensitive, low-speed industrial controls where PCB real estate permits through-hole mounting | Choose for legacy board refreshes needing drop-in replacement with reduced power draw and relaxed timing |
Compared with SN74AS157DR and SN74ALS158N, the SN74AS158DR uniquely balances high-speed inverted multiplexing (≤10.5 ns), 20 mA drive, and SOIC packaging - making it optimal for new SMT designs requiring minimal propagation latency and compact layout.
Availability
SN74AS158DR is available at Aetrix Electronics and suitable for industrial control systems, automated test equipment, and embedded instrumentation requiring stable component supply, long-term manufacturability, and RoHS-compliant SMT packaging.
Supply support for SN74AS158DR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic solutions, with over 50 years of innovation in digital logic families.
The SN74AS158DR belongs to TI's Advanced Schottky (AS) logic series, engineered for high-speed digital systems where propagation delay and drive strength outweigh power-efficiency priorities - targeting test gear, military avionics interfaces, and real-time control subsystems.
FAQ
What is the maximum propagation delay of the SN74AS158DR under recommended operating conditions?
The SN74AS158DR exhibits a maximum propagation delay of 10.5 ns (tPHL or tPLH) from the A/B select input to any output (Y) when operated at VCC = 4.5–5.5 V, CL = 50 pF, and RL = 500 Ω across the full 0°C to 70°C temperature range. This value is confirmed in the official SDAS081C datasheet switching characteristics table for SN74AS158.
Does the SN74AS158DR support 3-state (high-impedance) outputs?
No, the SN74AS158DR does not feature 3-state outputs. It uses totem-pole (push-pull) output drivers that actively drive both high and low logic states. When the strobe input G is high, all outputs (1Y–4Y) are forced high (not high-Z); only the data path is disabled via inversion logic - a key distinction from 3-state multiplexers like the 74AS257.
What is the purpose of the NC pins (pins 3 and 11) on the SN74AS158DR?
Pins 3 and 11 on the SN74AS158DR are designated No Connect (NC) - they have no internal bond wire or silicon connection. These pins must remain unconnected on the PCB; neither termination nor routing is permitted. Their presence accommodates die pad layout commonality across the SN74AS157/SN74AS158 family but serves no electrical function in SN74AS158DR operation.
Can the SN74AS158DR operate with a 3.3 V supply?
No, the SN74AS158DR is not rated for 3.3 V operation. Its recommended VCC range is 4.5 V to 5.5 V, and absolute maximum supply voltage is 7 V. Operating below 4.5 V risks failure to meet VIH/VIL thresholds, increased propagation delay, and unreliable output drive - use 74LVC or 74AUP series for 3.3 V logic compatibility.
How does the inverted output behavior of the SN74AS158DR affect system-level timing design?
The SN74AS158DR outputs the logical inverse of the selected input (e.g., if A/B = L and 1A = HIGH, then 1Y = LOW). This eliminates one external inverter stage, reducing total path delay by ~3–5 ns versus using a true-output mux plus discrete inverter - critical in setups with tight setup/hold windows, such as high-speed bus arbitration or synchronous sampling circuits using SN74AS158DR.
SN74AS158DR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AS
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Type:
- Multiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 400µA, 8mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74AS158DR FAQ
1.How can I place an order for SN74AS158DR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AS158DR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SN74AS158DR reliable?
The price and inventory of SN74AS158DR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AS158DR is usually 5 days.
3.What payment methods are accepted for SN74AS158DR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AS158DR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AS158DR?
SN74AS158DR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AS158DR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SN74AS158DR?
For technical support, including SN74AS158DR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AS158DR requirements.
6.How does Aetrix verify that SN74AS158DR is sourced from the original manufacturer or authorized distributors?
All SN74AS158DR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SN74AS158DR meets industry standards.
7.What is the process for return or replacement of SN74AS158DR?
All SN74AS158DR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AS158DR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SN74AS158DR part is unused and in its original packaging.
Return procedure for SN74AS158DR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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