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Texas Instruments SN74HCT157DR
- Part No.:
- SN74HCT157DR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74HCT157DR.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:9,527
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Product details
Overview
SN74HCT157DR from Texas Instruments is a high-speed CMOS quad 2-line-to-1-line data selector/multiplexer with active-low enable (G), operating at 4.5 V–5.5 V, delivering 15 ns typical propagation delay, ±6-mA output drive, and TTL-compatible inputs. It routes one of two 4-bit data sources to four outputs in digital control logic, bus selection, and address multiplexing applications.
For engineers reviewing the SN74HCT157DR datasheet, SN74HCT157DR pinout, SN74HCT157DR application, or SN74HCT157DR equivalent, key selection criteria include its SOIC-16 package, guaranteed 4.5–5.5 V operation, 15 ns tpd at 5.5 V/CL = 50 pF, low 80-µA max ICC, and buffered TTL-compatible input structure.
Technical Context
The SN74HCT157DR implements four independent 2:1 multiplexers sharing a common select (A/B) and strobe (G) input. Each channel selects between corresponding A and B inputs based on A/B state when G is low, with outputs disabled (high-impedance) when G is high.
Its HCT logic family ensures TTL-level input thresholds (VIH = 2 V min, VIL = 0.8 V max) while maintaining CMOS power efficiency. All inputs are buffered, and outputs drive up to 15 LSTTL loads with rail-to-rail swing under 6-mA load conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures compatibility with standard 5-V TTL and mixed-voltage systems without level-shifting. |
| Propagation Delay | 15 ns typical (VCC = 5.5 V, CL = 50 pF) - Enables reliable operation in 33-MHz synchronous bus timing paths. |
| Output Drive | ±6 mA at 5 V - Sufficient to directly drive 15 LSTTL loads or interface with legacy 74-series logic without buffers. |
| Input Compatibility | TTL voltage thresholds (VIH ≥ 2 V, VIL ≤ 0.8 V) - Allows direct connection to 74LS, 74ALS, and other TTL-family outputs. |
| Quiescent Current | 80 µA max (VCC = 5.5 V) - Supports low-static-power system design in always-on control modules. |
| Input Leakage | 1 µA max - Minimizes signal integrity risk in high-impedance node routing or battery-backed circuits. |
Pinout & Package
SN74HCT157DR is housed in a 16-pin SOIC (D) package per JEDEC MS-012, 1.27 mm pitch, with exposed pad not present and moisture sensitivity level 1 (260°C reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (G) | Strobe Enable | Active-low global enable; all outputs high-impedance when high. |
| 2 (1A) | Channel 1 Input A | First bit of source A for multiplexer channel 1. |
| 3 (1B) | Channel 1 Input B | First bit of source B for multiplexer channel 1. |
| 4 (1Y) | Channel 1 Output | Selected output (A or B) for channel 1, driven only when G = low. |
| 5 (2A) | Channel 2 Input A | Second bit of source A for multiplexer channel 2. |
| 6 (2B) | Channel 2 Input B | Second bit of source B for multiplexer channel 2. |
| 7 (2Y) | Channel 2 Output | Selected output (A or B) for channel 2, driven only when G = low. |
| 8 (GND) | Ground | Power return reference for all logic and I/O functions. |
| 9 (3Y) | Channel 3 Output | Selected output (A or B) for channel 3, driven only when G = low. |
| 10 (3B) | Channel 3 Input B | Third bit of source B for multiplexer channel 3. |
| 11 (3A) | Channel 3 Input A | Third bit of source A for multiplexer channel 3. |
| 12 (4Y) | Channel 4 Output | Selected output (A or B) for channel 4, driven only when G = low. |
| 13 (4B) | Channel 4 Input B | Fourth bit of source B for multiplexer channel 4. |
| 14 (4A) | Channel 4 Input A | Fourth bit of source A for multiplexer channel 4. |
| 15 (A/B) | Common Select | Global 2:1 select line determining whether A or B inputs pass to outputs. |
| 16 (VCC) | Supply Voltage | Positive supply rail for internal logic and output drivers (4.5–5.5 V). |
Key Features
| Feature | Design Value |
|---|---|
| Quad 2:1 Multiplexing | Four independent channels share one select (A/B) and one enable (G), reducing control lines in bus arbitration. |
| TTL-Compatible Inputs | Guaranteed VIH ≥ 2 V and VIL ≤ 0.8 V allow direct interfacing with legacy 74LS/ALS outputs without level shifters. |
| High-Current Outputs | ±6-mA drive capability supports fanout to 15 LSTTL loads, eliminating need for external buffers in most designs. |
| Low Power Consumption | 80-µA max ICC enables use in power-sensitive industrial controllers and standby-mode logic subsystems. |
| Buffered I/O Structure | Input and output buffering improves noise immunity and reduces capacitive loading effects on driving sources. |
Applications
| Microprocessor Address Bus Selection | Digital Signal Routing in Test Equipment |
|---|---|
|
Use Scenario: Selecting between two memory banks or peripheral address spaces during CPU instruction fetch cycles. IC Role / Device Role / Timing Role: Quad 2:1 data selector enabling dynamic address space switching with single-cycle latency. Use Value: Eliminates need for discrete logic gates or CPLDs in simple dual-bank memory mapping, saving board area and BOM cost. |
Use Scenario: Routing signal paths between multiple DUT interfaces and measurement instruments in automated test fixtures. IC Role / Device Role / Timing Role: Signal path selector providing deterministic, low-latency routing of parallel digital signals. Use Value: Enables reconfigurable test setups using software-controlled A/B selection, reducing fixture complexity and changeover time. |
| Industrial PLC I/O Multiplexing | Legacy System Bus Arbitration |
|
Use Scenario: Consolidating sensor inputs from redundant analog front-ends into a single ADC interface within a safety-critical controller. IC Role / Device Role / Timing Role: Fault-tolerant input selector ensuring continuity of monitoring data during sensor failure detection. Use Value: Provides hardware-level redundancy management without microcontroller intervention, meeting SIL-2 functional safety requirements. |
Use Scenario: Arbitrating between two DMA controllers competing for access to a shared peripheral bus in embedded systems. IC Role / Device Role / Timing Role: Bus resource selector resolving contention by gating one controller's address/data lines to peripherals. Use Value: Delivers deterministic, sub-20-ns arbitration response-critical for real-time DMA coherency in motion control systems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad 2:1 multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC157DR | CMOS input thresholds (VIH = 3.15 V min), higher tpd (24 ns typ), lower drive (±5.2 mA) | Requires clean 5-V supply and stronger drive sources; unsuitable for direct TTL interfacing | Select when lowest power (2 µA ICC) is critical and system uses only CMOS logic families. |
| 74LVC157PW | 3.3-V only (1.65–3.6 V), smaller TSSOP-16 package, 3.5 ns tpd, ±24 mA drive | Not voltage-compatible with 5-V systems; requires level translation if used alongside SN74HCT157DR | Select for new 3.3-V designs needing faster switching and higher drive, where board space is constrained. |
Compared with SN74HC157DR and 74LVC157PW, the SN74HCT157DR uniquely bridges 5-V TTL and CMOS domains with guaranteed input compatibility, making it the only choice for mixed-logic upgrades or legacy system integration without redesign.
Availability
SN74HCT157DR is available at Aetrix Electronics and suitable for industrial PLCs, automated test equipment, microprocessor-based control systems, and legacy system upgrades requiring stable component supply across long production lifecycles.
Supply support for SN74HCT157DR 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 founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The SN74HCT157DR belongs to TI's HCT logic family, engineered specifically for seamless interoperability between TTL and CMOS systems in industrial control, instrumentation, and computing infrastructure.
FAQ
What is the maximum operating temperature range for the SN74HCT157DR?
The SN74HCT157DR is rated for operation from −40°C to +85°C, matching industrial-grade requirements. This range is confirmed in TI's official packaging addendum and applies to all active SOIC-D variants including SN74HCT157DR, SN74HCT157DR1G4.A, and SN74HCT157DR.A.
Does the SN74HCT157DR support 3.3-V operation?
No, the SN74HCT157DR requires a minimum supply voltage of 4.5 V and is not specified for reliable operation below that threshold. Its input thresholds and output drive characteristics are optimized for 5-V systems, and operation at 3.3 V may result in undefined logic states or excessive propagation delay.
Is the SN74HCT157DR pin-compatible with the SN74LS157?
Yes, the SN74HCT157DR is pin-compatible with the SN74LS157 in the SOIC-16 (D) package, sharing identical pin assignments for G, A/B, all A/B inputs, Y outputs, VCC, and GND. However, SN74HCT157DR draws significantly less quiescent current and offers improved noise immunity due to CMOS input structure.
What is the meaning of the "R" suffix in SN74HCT157DR?
The "R" in SN74HCT157DR denotes tape-and-reel packaging: 2500 units per large reel. This distinguishes it from tube-packaged variants like SN74HCT157N and supports automated SMT assembly. The marking "HCT157" appears on the top-side of each SN74HCT157DR unit.
Can unused inputs on the SN74HCT157DR be left floating?
No - all unused inputs on the SN74HCT157DR must be tied to either VCC or GND to prevent metastability, excessive current draw, or erratic output behavior. TI's datasheet explicitly mandates this in Note 3 under Recommended Operating Conditions, citing risks outlined in application report SCBA004.
SN74HCT157DR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Multiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 6mA, 6mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74HCT157DR FAQ
1.How can I place an order for SN74HCT157DR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT157DR 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 SN74HCT157DR reliable?
The price and inventory of SN74HCT157DR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT157DR is usually 5 days.
3.What payment methods are accepted for SN74HCT157DR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCT157DR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HCT157DR?
SN74HCT157DR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT157DR 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 SN74HCT157DR?
For technical support, including SN74HCT157DR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT157DR requirements.
6.How does Aetrix verify that SN74HCT157DR is sourced from the original manufacturer or authorized distributors?
All SN74HCT157DR 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 SN74HCT157DR meets industry standards.
7.What is the process for return or replacement of SN74HCT157DR?
All SN74HCT157DR units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT157DR, 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 SN74HCT157DR part is unused and in its original packaging.
Return procedure for SN74HCT157DR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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